Steel is an alloy of iron with carbon.

Depending on the percentage of carbon " WITH"in such an alloy, steels have different properties and characteristics. By adding various chemical elements to the alloy during smelting (called" alloying elements "), steels with a wide variety of properties can be obtained. Steels with similar characteristics were collected in groups.

In order for the steel to be called stainless, the chromium content in the composition of such steel must be more than 10.5% and at the same time the carbon content is low (no more than 1.2%). The presence of chromium gives the steel its corrosion resistance - hence the name "stainless". In addition to chromium, as an "indispensable stainless component", alloying elements can also be present in the composition of stainless steel: nickel (Ni), molybdenum (Mo), Titanium (Ti), Niobium (Nb), Sulfur (S), Phosphorus (P) and other elements whose combination determines the properties of the steel.

Main grades of stainless steels for fasteners

Historically, the development and smelting of new stainless steels and alloys is closely associated with advanced technology industries: aircraft and rocketry. The leading states in the world in these branches of mechanical engineering were the USSR and the USA, they were in a state of "cold war" for a long time and each went its own way. In Europe, the technological leader in the twentieth century was and is Germany. Each of them developed its own classification of stainless steels: in the USA - the system AISI, in Germany - DIN, in USSR - GOST.

For a very long time, there was no question of any cooperation between these three leaders - hence the large number of today's standards for stainless steels, and their very difficult, and sometimes absent, interchangeability.

The United States and Germany are somehow simpler: after all, there has been mutual trade between these countries for decades technical means and technology, which inevitably led to mutual adaptation, and in the area of ​​stainless steel standards too. The most difficult thing is for the countries of the former USSR, where standards developed in isolation from the rest of the world, and today, for many brands of imported stainless steels there are simply no analogues - or vice versa: there are no imported analogues of Soviet stainless steels.

This whole situation is extremely slowing down and complicates the development of domestic mechanical engineering, which is already "on its knees."

As a result, we have the following world standards for stainless steels:

• DIN- Deutsche Industrie Norm
• RU- European standard EN 10027
• DIN EN- German edition of the European Standard
• ASTM- American Society for Testing and Materials
• AISI- American Iron and Steel Institute
• AFNOR- Association Francaise de Normalization
• GOST- State standard

There are no mass or serial manufacturers of stainless steel fasteners in Ukraine, so we all have to study and adapt to foreign classification and marking of stainless steels and fasteners.

In recent years, Russian standards for stainless fasteners, adopting the terminology and markings from European standards (for example, GOST R ISO 3506-2-2009). In Ukraine, most likely, no changes and innovations are expected in the near future ...

And yet, the stainless steels most used for the production of fasteners have approximate analogues in various classification systems - the main ones are given in the following table of correspondences of stainless steel grades for fasteners:

Stainless Steel Standards				Alloying elements content,%
*	DIN	AISI	GOST	C	Mn	Si	Cr	Ni	Mo	Ti
C1	1.4021	420	20X13	0,20	1,5	1,0	12-14
F1	1.4016	430	12X17	0,08	1,0	1,0	16-18
A1	1.4305	303	12Х18Н10Е	0,12	6,5	1,0	16-19	5-10	0,7
A2	1.4301	304	12X18H10	0,07	2,0	0,75	18-19	8-10
	1.4948	304H	08X18H10	0,08	2,0	0,75	18-20	8-10,5
	1.4306	304L	03X18H11	0,03	2,0	1,0	18-20	10-12
A3	1.4541	321	08X18H10T	0,08	2,0	1,0	17-19	9-12		5xS-0.7
A4	1.4401	316	03Х17Н14М2	0,08	2,0	1,0	16-18	10-14	2-2,5
	1.4435	316S	03Х17Н14М3	0,08	2,0	1,0	16-18	12-14	2,5-3
	1.4404	316L	03Х17Н14М3	0,03	2,0	1,0	17-19	10-14	2-3
A5	1.4571	316Ti	08Х17Н13М2Т	0,08	2,0	0,75	16-18	11-12,5	2-3	5xS-0.8

In turn, depending on the composition and properties, stainless steels are divided into several subgroups, indicated in the first column:

* - designation of subgroups of stainless steels:

• A1, A2, A3, A4, A5- Austenitic stainless steels - in general, non-magnetic or weakly magnetic steels with a main constituent of 15-20% chromium and 5-15% nickel, which increases corrosion resistance. They can be cold formed, heat treated and welded well. Indicated by an initial letter " A"It is the austenitic group of stainless steels that is most widely used in industry and in the manufacture of fasteners.
• C1- Martensitic stainless steels are significantly harder than austetitic steels and can be magnetic. They are hardened by quenching and tempering, like simple carbon steels, and are mainly used in the manufacture of cutlery, cutting tools and general engineering. More susceptible to corrosion. Indicated by an initial letter " WITH"
• F1- Ferritic stainless steels are much softer than martensitic ones due to their low carbon content. They are also magnetic. Indicated by an initial letter " F"

Austenitic stainless steels of subgroups A2, A4 and others

Marking system for austenitic stainless steels with the letter " BUT"developed in Germany for simplified marking of fasteners. Let us examine in more detail austenitic steels by subgroups:

Subgroup A1

Steel subgroups A1 are characterized by a high sulfur content and, therefore, are most susceptible to corrosion. Become A1 have high hardness and wear resistance.

They are used in the manufacture of spring washers, pins, some types of cotter pins, as well as for parts of movable joints.

Subgroup A2

The most common subgroup of stainless steels in the production of fasteners A2... These are non-toxic, non-magnetic, non-hardenable, corrosion-resistant steels. Easily weldable without becoming brittle. Initially, steels of this subgroup are non-magnetic, but they can exhibit magnetic properties as a result of cold machining - forging, upsetting. They have good resistance to corrosion in the atmosphere and in clean water.

Fasteners and steel products A2 not recommended for use in acids and chlorine-containing environments (e.g. swimming pools and salt water).

Steel fasteners A2 maintains performance up to temperatures of - 200˚C.

In the German classification DIN, A2

• DIN 1.4301 ( American counterpart AISI 304, Soviet closest analogue 12X18H10),
• DIN 1.4948 ( American counterpart AISI 304H, Soviet closest analogue 08X18H10),
• DIN 1.4306 ( American counterpart AISI 304L, Soviet closest analogue 03X18H11).

Therefore, if you see a marking on a bolt, screw or nut A2, it is most likely that this fastener is made of one of these three steels. It is usually difficult to determine more precisely due to the fact that the manufacturer indicates only the marking A2.

All three steels included in the subgroup A2 do not contain Titanium ( Ti) - this is due to the fact that steel A2, mainly, products are produced by stamping, and the addition of titanium to the stainless steel composition significantly reduces the ductility of such steel, and, therefore, such steel with titanium is very difficult to stamp.

Noteworthy are the numbers 18 and 10 in the Soviet designation. 12X18H10 analogue of steel DIN 1.4301... On imported stainless steel dishes, the designation 18/10 is often found - this is nothing more than an abbreviation for stainless steel with a percentage of 18% chromium and 10% nickel - i.e. DIN 1.4301.

Become A2 are often used for the manufacture of dishes and elements of food equipment - therefore the popular name of such steels is closely related to the field of application of steels A2- "food grade stainless steel". Some semantic confusion arose here. The name "food grade stainless steel" is associated with the field of application, not with the properties of steel A2, and this is not quite the correct name, since it is titanium itself that has antibacterial properties - and only stainless steel containing titanium in its composition can rightfully be called "food grade".

Fasteners made of stainless steel subgroup A2 may have some magnetic properties in strong magnetic fields. By themselves have become subgroups A2 non-magnetic, some magnetism appears in bolts, screws, washers and nuts as a result of stresses arising from cold deformation - stamping.

A manufacturing plant, both utensils and fasteners, can use the above-mentioned stainless steels additionally alloyed in very small quantities with some other elements, for example, Molybdenum, to give their products special consumer properties. You can only find out about this with the help spectral analysis in the laboratory - the manufacturer himself may consider the composition of the steel a "trade secret" and indicates, for example, only A2.

Subgroup A3

Steel subgroups A3 have similar properties to steels A2, but at the same time additionally alloyed with titanium, niobium or tantalum. This increases the corrosion resistance of steels at high temperatures and imparts spring properties.

They are used in the manufacture of parts with high rigidity and spring properties (washers, rings, etc.)

Subgroup A4

The second most common subgroup of stainless steels for fasteners is the subgroup A4... Become A4 their properties are also similar to A2 steels, but additionally alloyed with the addition of 2-3% Molybdenum. Molybdenum gives steels A4 significantly higher corrosion resistance in aggressive environments and acids.

Steel fasteners and rigging A4 They are highly resistant to chlorine-containing media and salt water and are therefore recommended for use in shipbuilding.

Steel fasteners A4 maintains performance up to temperatures - 60˚C.

In the German classification DIN, based on the table, such steel A4 can match one of three stainless steels:

• DIN 1.4401 ( American counterpart AISI 316, Soviet closest analogue 03Х17Н14М2)
• DIN 1.4404 ( American counterpart AISI 316L, Soviet closest analogue 03Х17Н14М3)
• DIN 1.4435 ( American counterpart AISI 316S, Soviet closest analogue 03Х17Н14М3)

Since the subgroup A4 has increased corrosion resistance not only in the atmosphere or water, but also in aggressive environments - therefore, the popular name for steel A4"acid-resistant" or also called "molybdenum" because of the content of molybdenum in the steel.

Subgroup stainless steels A4 practically do not have magnetic properties.

Resistance to external conditions different environments for stainless fasteners is given in the article " "

Subgroup A5

Steel subgroup A5 has properties similar to those of steels A4 and with steels A3, since it is also additionally alloyed with titanium, niobium or tantalum, but with a different percentage of alloying additions. These features give steel A5 increased resistance to high temperatures.

Steel A5 as well as A3, has spring properties and is used for the manufacture of various fasteners with high rigidity and spring properties. At the same time, the performance of steel fasteners A5 persists at high temperatures and in aggressive environments.

Applicability of stainless steels for the manufacture of fasteners

Here is a short table of the most common types of fasteners and corresponding to these types of stainless steels:

Fastener name	Subgroup of steels	DIN	AISI
	A2, A4
	A2, A4	1.4301, 1.4306, 1.4948, 1.4401, 1.4404, 1.4435	304, 304H, 304L, 316, 316L, 316S
	A2, A4	1.4301, 1.4306, 1.4948, 1.4401, 1.4404, 1.4435	304, 304H, 304L, 316, 316L, 316S
,		1.4122, 1.4310	440A, 301
		1.4122, 1.4310	440A, 301
		1.4122, 1.4310	440A, 301
	A2, A4	1.4301, 1.4306, 1.4948, 1.4401, 1.4404, 1.4435	304, 304H, 304L, 316, 316L, 316S
	A2, A4	1.4301, 1.4306, 1.4948, 1.4401, 1.4404, 1.4435	304, 304H, 304L, 316, 316L, 316S
	A1, A5	1.4305, 1.4570, 1.4845	303, 316Ti, 310S
		1.4122, 1.4310	440A, 301
	A1, A2	1.4301, 1.4306, 1.4948	303, 304, 304H, 304L

Also, the listed types of fasteners can be made by manufacturers from other grades of stainless steels other than those listed in the table with minor additional "secret" alloying additions to impart specific properties to the steel. For example, retaining rings can be made from such a "special" subgroup stainless steel A2, which is a trade secret of the manufacturer.

Most common stainless steels

Below is a more complete table of the most common types of stainless steels and their correspondence different classifications standards.

Chemical composition according to EN DIN AISI ASTM AFNOR Stainless chromium-nickel steels (Cr + Ni) X 5 CrNi 18 10 1.4301 304 S 30400 Z 6 CN 18 09 X 5 CrNi 18 12 1.4303 305 Z 8 CN 18 12 X 10 CrNi S 18 9 1.4305 303 S 30300 Z 10 CNF 18 09 X 2 CrNi 19 11 1.4306 304L S 30403 Z 3 CN 18 10 X 12 CrNi 17 7 1.4310 301 S 30100 Z 11 CN 18 08 X 2 CrNiN 18 10 1.4311 304LN S 30453 Z 3 CN 18 10 Az X 1 CrNi 25 21 1.4335 310L Z 1 CN 25 20 X 1 CrNiSi 18 15 1.4361 S 30600 Z 1 CNS 17 15 X 6 CrNiTi 18 10 1.4541 321 S 32100 Z 6 CNT 18 10 X 6 CrNiNb 18 10 1.4550 347 (H) S 34700 Z 6 CNNb 18 10 Stainless chromium-nickel molybdenum steels (Cr + Ni + Mo) X 5 CrNiMo 17 12 2 1.4401 316 S 31600 Z 7 CND 17 11 02 X 2 CrNiMo 17 13 2 1.4404 316L S 31603 Z 3 CND 18 12 2 X 2 CrNiMoN 17 12 2 1.4406 316LN S 31653 Z 3 CND 17 11 Az X 2 CrNiMoN 17 13 3 1.4429 316LN (Mo +) (S 31653) Z 3 CND 17 1 2 Az X 2 CrNiMo 18 14 3 1.4435 316L (Mo +) S 31609 Z 3 CND 18 14 03 X 5 CrNiMo 17 13 3 1.4436 316 (Mo) Z 6 CND 18 12 03 X 2 CrNiMo 18 16 4 1.4438 317L S 31703 Z 3 CND 19 15 04 X 2 CrNiMoN 17 13 5 1.4439 317LN S 31726 Z 3 CND 18 14 05 Az X 5 CrNiMo 17 13 1.4449 (317) Z 6 CND 17 12 04 X 1 CrNiMoN 25 25 2 1.4465 N08310 / S31050 Z 2 CND 25 25 Az X 1 CrNiMoN 25 22 2 1.4466 S 31050 Z 2 CND 25 22 Az X 4 NiCrMoCuNb 20 18 2 1.4505 Z 5 NCDUNb 20 18 X 5 NiCrMoCuTi 20 18 1.4506 Z 5 NCDUT 20 18 X 5 NiCrMoCuN 25 20 6 1.4529 S31254 (±) X 1 NiCrMoCu 25 20 5 1.4539 904L N 08904 Z 2 NCDU 25 20 X 1 NiCrMoCu 31 27 4 1,4563 N 08028 Z 1 NCDU 31 27 03 X 6 CrNiMoTi 17 12 2 1.4571 316Ti S 31635 Z 6 CNDT 17 12 X 3 CrNiMoTi 25 25 1.4577 Z 5 CNDT 25 24 X 6 CrNiMoNb 17 12 2 1.4580 316Cb / Nb C31640 Z 6 CNDNb 17 12 X 10 CrNiMoNb 18 12 1.4582 318 Z 6 CNDNb 17 13 Duplex stainless steels (DUPLEX) X 2 CrNiN 23 4 1.4362 S 32304 / S 39230 Z 3CN 23 04 Az X 2 CrNiMoN 25 7 4 1.4410 S 31260 / S 39226 Z 3 CND 25 07 Az X 3 CrNiMoN 27 5 2 1.4460 329 S 32900 Z 5 CND 27 05 Az X 2 CrNiMoN 22 5 3 1.4462 (329 LN) / F 51 S 31803 / S 39209 Z 3 CND 22 05 Az X 2 CrNiMoCuWN 25 7 4 1.4501 F55 S 32760 X 2 CrNiMoCuN 25 6 3 1.4507 S 32550 / S 32750 Z 3 CNDU 25 07 Az X 2 CrNiMnMoNbN 25 18 5 4 1.4565 S 24565 High temperature stainless steels (600 ° C - 1200 ° C) X 10 CrAl 7 1.4713 Z 8 CA 7 X 10 CrSiAl 13 1.4724 Z 13 C 13 X 10CrAI 18 1.4742 442 S 44200 Z 12 CAS 18 X 18 CrN 28 1.4749 446 S 44600 Z 18 C 25 X 10 CrAlSi 24 1.4762 Z 12 CAS 25 X 20 CrNiSi 25 4 1.4821 327 Z 20 CNS 25 04 X 15 CrNiSi 20 12 1.4828 302B / 309 S 30215/30900 Z 17 CNS 20 12 X 6 CrNi 22 13 1.4833 309 (S) S 30908 Z 15 CN 24 13 X 15 CrNiSi 25 20 1.4841 310/314 S 31000/31400 Z 15 CNS 25 20 X 12 CrNi 25 21 1.4845 310 (S) S 31008 Z 8 CN 25 20 X 12 NiCrSi 35 16 1.4864 330 N 08330 Z 20 NCS 33 16 X 10 NiCrAlTi 32 20 1.4876 N 08800 Z 10 NC 32 21 X 12 CrNiTi 18 9 1.4878 321H S 32109 Z 6 CNT 18 12 X 8 CrNiSiN 21 11 1.4893 S 30815 X 6 CrNiMo 17 13 1.4919 316H S 31609 Z 6 CND 17 12 X 6 CrNi 18 11 1.4948 304H S 30409 Z 6 CN 18 11 X 5 NiCrAlTi 31 20 1.4958 N 08810 Z 10 NC 32 21 X 8 NiCrAlTi 31 21 1.4959 N 08811 Tool stainless steels (Cr) X 6 Cr 13 1.4000 410S S 41008 Z 8 C 12 X 6 CrAl 13 1.4002 405 S 40500 Z 8 CA 12 X 12 CrS 13 1.4005 416 S 41600 Z 13 CF 13 X 12 Cr 13 1.4006 410 S41000 Z 10 C 13 X 6 Cr 17 1.4016 430 S 43000 Z 8 C 17 X 20 Cr 13 1.4021 420 S 42000 Z 20 C 13 X 15 Cr 13 1.4024 420S J 91201 Z 15 C 13 X 30 Cr 13 1.4028 420 J 91153 Z 33 C 13 X 46 Cr 13 1.4034 (420) Z 44 C 14 X 19 CrNi 17 2 1.4057 431 S 43100 Z 15 CN 16 02 X 14 CrMoS 17 1.4104 430F S 43020 Z 13 CF 17 X 90 CrMoV 18 1.4112 440B S 44003 Z 90 CDV 18 X 39 CrMo 17 1 1.4122 440A Z 38 CD 16 01 X 105 Cr Mo 17 1.4125 440C S 44004 / S 44025 Z 100 CD 17 X 5 CrTi 17 1.4510 430Ti S 43036 / S 43900 Z 4 CT 17 X 5 CrNiCuNb 16 4 1.4542 630 S17400 Z 7 CNU 17 04 X 5 CrNiCuNb 16 4 1.4548 630 S17400 Z 7 CNU 17 04 X 7 CrNiAl 17 7 1.4568 631 S17700 Z 9 CNA 1 7 07 Designations of chemical elements in the table: Fe - Iron C - Carbon Mn - Manganese Si - Silicon Cr - Chromium Ni - Nickel Mo - Molybdenum Ti - Titanium

Duplex stainless steels are becoming more common. They are made by all major stainless steel manufacturers - and that's why whole line reasons:

• High strength to reduce product weight
• High corrosion resistance, especially stress corrosion cracking

Duplex steels conferences are held every 2-3 years, featuring dozens of in-depth technical articles. Goes active promotion of this type of steel on the market. New grades of these steels are constantly appearing.

But despite all this interest, the share of duplex steels in the world market is, according to the most optimistic estimates, from 1 to 3%. The purpose of this article is to in simple words explain the features of this type of steel. Both advantages and disadvantages will be described duplex stainless steel products.

Overview of Duplex Stainless Steels

The idea for duplex stainless steels originated in the 1920s, and the first melting took place in 1930 in Avesta, Sweden. However, only the last 30 years have seen a noticeable increase in the use of duplex steels. This is explained mainly by the improvement of steel production technology, especially the processes for regulating the nitrogen content in steel.

Traditional austenitic steels such as AISI 304 (analogs to DIN 1.4301 and 08X18H10) and ferritic steels such as AISI 430 (analogs to DIN 1.4016 and 12X17) are fairly easy to manufacture and easy to process. As their names suggest, they consist primarily of one phase: austenite or ferrite. Although these types have a wide range of applications, both of these types have their own technical disadvantages:

In austenitic ones - low strength (conditional yield point 0.2% in the state after austenitizing 200 MPa), low resistance to stress corrosion cracking

Ferritic ones have low strength (slightly higher than that of austenitic ones: the conventional yield point of 0.2% is 250 MPa), poor weldability at large thicknesses, low-temperature brittleness

In addition, the high nickel content in austenitic steels leads to higher prices, which is undesirable for most end users.

The main idea behind duplex steels is to select a chemical composition that produces approximately the same amount of ferrite and austenite. This phase composition provides the following advantages:

1) High strength - the range of the nominal yield strength of 0.2% for modern duplex steel grades is 400-450 MPa. This allows you to reduce the cross section of the elements, and hence their mass.

This advantage is especially important in the following areas:

• Pressure vessels and tanks
• Building structures such as bridges

2) Good weldability of large thicknesses - not as simple as with austenitic, but much better than with ferritic ones.

3) Good toughness - much better than ferritic steels, especially at low temperatures: usually up to minus 50 degrees Celsius, in some cases up to minus 80 degrees Celsius.

4) Resistance to corrosion cracking (SCC) - traditional austenitic steels are particularly prone to this type corrosion. This advantage is especially important in the manufacture of structures such as:

• Hot water tanks
• Brewing tanks
• Concentrating plants
• Pool frames

How the balance of austenite / ferrite is achieved

To understand how duplex steel is obtained, you can first compare the composition of two well-known steels: austenitic - AISI 304 (analogues of DIN 1.4301 and 08X18H10) and ferritic - AISI 430 (analogues of DIN 1.4016 and 12X17).

Structure	Brand	EN designation
Ferritic									16,0-18,0
Austenitic									17,5-19,5	8,0-10,5

The main elements of stainless steels can be divided into ferritizing and austenitizing. Each of the elements contributes to the formation of a particular structure.

Ferritizing elements are Cr (chromium), Si (silicon), Mo (molybdenum), W (tungsten), Ti (titanium), Nb (niobium)

Austenitizing elements are C (carbon), Ni (nickel), Mn (manganese), N (nitrogen), Cu (copper)

Ferritizing elements predominate in AISI 430 steel, therefore its structure is ferritic. Steel AISI 304 has an austenitic structure mainly due to its content of about 8% nickel. To obtain a duplex structure with a content of each phase of about 50%, a balance of austenitizing and ferritizing elements is required. This is the reason why the nickel content of duplex steels is generally lower than that of austenitic steels.

Below is a typical composition of duplex stainless steel:

Brand	EN / UNS number		Approximate content
LDX 2101	1.4162/ S32101	Low alloyed
	1.4062 / S32202	Low alloyed
	1.4482/ S32001	Low alloyed
	1.4362/ S32304	Low alloyed
	1.4462/ S31803 / S32205	Standard
	1.4410/ S32750	Super
Zeron 100	1.4501/ S32760	Super
Ferrinox255/ Uranus 2507Cu	1.4507/ S32520 / S32550	Super

Some of the newly developed grades use a combination of nitrogen and manganese to significantly reduce nickel content. This has a positive effect on price stability.

Currently, the technology for the production of duplex steels is still developing. Therefore, each manufacturer promotes own brand... By all accounts, there are too many grades of duplex steel now. But apparently, we will observe such a situation until the "winners" emerge among them.

Corrosion resistance of duplex steels

Due to the variety of duplex steels, when determining corrosion resistance, they are usually listed together with austenitic and ferritic steels. There is no single measure of corrosion resistance yet. However, it is convenient to use the Pitting Resistance Numerical Equivalent (PREN) to classify steel grades.

PREN =% Cr + 3.3 x% Mo + 16 x% N

Below is a table of the corrosion resistance of duplex steels compared to austenitic and ferritic grades.

Brand	EN / UNS number		Indicative PREN
	1.4016/ S43000	Ferritic
	1.4301/ S30400	Austenitic
	1.4509/ S43932	Ferritic
	1.4482/ S32001	Duplex
	1.4401/ S31600	Austenitic
	1.4521/ S44400	Ferritic
316L 2.5 Mo		Austenitic
2101 LDX	1.4162/ S32101	Duplex
	1.4362/ S32304	Duplex
	1.4062 / S32202	Duplex
	1.4539/ N08904	Austenitic
	1.4462/ S31803 / S32205	Duplex
Zeron 100	1.4501/ S32760	Duplex
Ferrinox 255 / Uranus 2507Cu	1.4507/ S32520 / S32550	Duplex
	1.4410/ S32750	Duplex
	1.4547/ S31254	Austenitic

It should be noted that this table can only serve as a guide when choosing a material. It is always necessary to consider how suitable a particular steel is for a particular corrosive environment.

Stress Corrosion Cracking (SCC)

SCC is one of the types of corrosion that occurs when there is a certain set of external factors:

• Tensile stress
• Corrosive environment
• Sufficiently high temperatures Usually 50 degrees Celsius, but in some cases, such as swimming pools, it can occur at temperatures around 25 degrees Celsius.

Unfortunately, common austenitic steels such as AISI 304 (analogs of DIN 1.4301 and 08X18H10) and AISI 316 (analogue of 10X17H13M2) are most susceptible to SCC. The following materials have much higher CR resistance:

• Ferritic stainless steels
• Duplex stainless steels
• Austenitic stainless steels with a high nickel content

The SCC resistance allows duplex steels to be used in many processes at high temperatures, in particular:

• In water heaters
• In the brewing tanks
• In desalination plants

Stainless steel pool frames are known for their SCC tendency. The use of conventional austenitic stainless steels in their manufacture, such as AISI 304 (analogue 08X18H10) and AISI 316 (analogue 10X17H13M2) is prohibited. Austenitic steels with a high nickel content, such as 6% Mo grades, are best suited for this purpose. However, in some cases, duplex steels such as AISI 2205 (DIN 1.4462) and super duplex steels can be considered as alternatives.

Factors hindering the proliferation of duplex steels

An attractive combination of high strength, wide range of corrosion resistance values, medium weldability, in theory, should carry great potential for increasing the share of duplex stainless steels in the market. However, it is important to understand what the disadvantages of duplex stainless steels are and why they are likely to remain niche players.

The advantage of high strength instantly turns into flaw, as soon as it comes to the manufacturability of material processing by pressure and machining. High strength also means lower plastic deformation than austenitic steels. Therefore, duplex steels are practically unsuitable for the production of products in which high ductility is required. And even when the ability to plastic deformation is at an acceptable level, still more force is required to give the required shape to the material, such as when bending pipes. There is one exception to the rule regarding poor machinability: LDX 2101 (EN 1.4162) from Outokumpu.

The smelting process for duplex stainless steels is much more complex than that of austenitic and ferritic steels. If the production technology is violated, in particular heat treatment, in addition to austenite and ferrite, a number of undesirable phases can form in duplex steels. The two most significant phases are depicted in the diagram below.

Click on the image to enlarge.

Both phases lead to the appearance of brittleness, that is, a loss of impact strength.

The formation of a sigma-phase (more than 1000 ° C) most often occurs when the cooling rate is insufficient during manufacturing or welding. The more alloying elements in the steel, the higher the likelihood of the formation of a sigma phase. Therefore, super duplex steels are most susceptible to this problem.

The 475 degree brittleness results from the formation of a phase called α ′ (alpha bar). Although the most dangerous temperature is 475 degrees Celsius, it can form at lower temperatures, up to 300 degrees C. This imposes restrictions on the maximum operating temperature of duplex steels. This limitation further narrows the range of possible applications.

On the other hand, there is a limitation on the minimum operating temperature of duplex steels, for which it is higher than that of austenitic steels. Unlike austenitic steels, duplex steels exhibit a brittle-ductile transition during impact testing. The standard test temperature for steels used in structures for offshore oil and gas production is minus 46 ° C. Duplex steels are generally not used at temperatures below minus 80 degrees Celsius.

A brief overview of the properties of duplex steels

• Design strength is twice that of austenitic and ferritic stainless steels
• Wide range of corrosion resistance values, allowing you to select the grade for a specific task
• Good impact resistance up to minus 80 ° С, limiting use in cryogenic environments.
• Exceptional resistance to stress corrosion cracking
• Good weldability of large cross-sections
• Greater difficulty in machining and stamping than austenitic steels
• The maximum operating temperature is limited to 300 degrees Celsius

Material taken from the British Stainless Steel Association website www.bssa.org.uk

Analogs of Russian and foreign steels

The countries and their applicable metal standards are listed below:

• Australia - AS (Australian Standard)
• Austria - ONORM
• Belgium - NBN
• Bulgaria - BDS
• Hungary - MSZ
• Great Britain - B.S. (British Standard)
• Germany - DIN (Deutsche Normen), WN
• European Union - EN (European Norm)
• Italy - UNI (Italian National Standards)
• Spain - UNE (Espaniol National Standards)
• Canada - CSA (Canadian Standards Association)
• China - GB
• Norway - NS (Standards Norway)
• Poland - PN (Poland Norm)
• Romania - STAS
• Russia - GOST (State standard) , THAT (Specifications)
• USA - AISI (American Iron and Steel Institute), ACI (American Concrete Institute), ANSI (American National Standards Institute), AMS (American Mathematical Society: Mathematics Research and Scholarship), API (American Petroleum Institute), ASME (American Society of Mechanical Engineers), ASTM (American Society of Testing and Materials), AWS (American Welding Society), SAE (Society of Automotive Engineers), UNS
• Finland - SFS (Finnish Standards Association)
• France - AFNOR NF (association francaise de normalization)
• Czech Republic - CSN (Czech State Norm)
• Sweden - SS (Swedish Standard)
• Switzerland - SNV (Schweizerische Normen-Vereinigung)
• Yugoslavia - JUS
• Japan - JIS (Japanese Industrial Standart)
• International standard - ISO (International Organization for Standardization)

In the United States, there are several systems of designation for metals and alloys associated with existing organizations on standardization. The most famous organizations are:

• AISI - American Iron and Steel Institute
• ACI - American Casting Institute
• ANSI - American National Standards Institute
• AMS - Aerospace Materials Specification
• ASME - American Society of Mechanical Engineers
• ASTM - American Society for Testing Materials
• AWS - American Welding Society
• SAE - Society of Engineers - Motorists

The following are the most popular steel designations used in the United States.

AISI notation system:

Carbon and alloy steels:
In the AISI designation system, carbon and alloy steels are generally identified with four numbers. The first two digits indicate the number of the steel group, and the last two - the average carbon content in steel multiplied by 100. So steel 1045 belongs to the group 10XX high-quality structural steels (non-sulfonated with a Mn content of less than 1%) and contains about 0.45% carbon.
Steel 4032 is doped (group 40XX), with an average content of C - 0.32% and Mo - 0.2 or 0.25% (the actual content of C in steel 4032 - 0.30 - 0.35%, Mo - 0.2 - 0.3%).
Steel 8625 is also doped (group 86XX) with an average content: C - 0.25% (real values ​​0.23 - 0.28%), Ni - 0.55% (0.40 - 0.70%), Cr - 0.50% (0.4 - 0.6%), Mo - 0.20% (0.15 - 0.25%) ...
In addition to four numbers, letters can also be found in the names of steels. Moreover, the letters B and L, meaning that the steel is alloyed with boron (0.0005 - 0.03%) or lead (0.15 - 0.35%), respectively, are placed between the second and third digits of its designation, for example: 51B60 or 15L48.
Letters M and E put in front of the name of steel, this means that the steel is intended for the production of irresponsible long products (letter M) or smelted in an electric furnace (letter E). The letter may be present at the end of the steel name H, meaning that the characteristic feature of this steel is hardenability.

Stainless steels:
AISI designations for standard stainless steels include three numbers followed by, in some cases, one, two or more letters. The first digit of the designation determines the steel grade. So the designations of austenitic stainless steels begin with numbers 2XX and 3XX, while ferritic and martensic steels are defined in the class 4XX... Moreover, the last two figures, unlike carbon and alloy steels, have nothing to do with chemical composition, but simply determine the serial number of the steel in the group.

Designations in carbon steels:
10XX - Non-sulfonated steels, Mn: less than 1%
11XX - Resulfinated steels
12XX - Re-phosphorized and resulfinated steels
15XX - Non-sulfonated steels, Mn: more than 1%

Alloy steel designations:
13XX - Mn: 1.75%
40XX - Mo: 0.2, 0.25% or Mo: 0.25% and S: 0.042%
41XX - Cr: 0.5, 0.8 or 0.95% and Mo: 0.12, 0.20 or 0.30%
43XX - Ni: 1.83%, Cr: 0.50 - 0.80%, Mo: 0.25%
46XX - Ni: 0.85 or 1.83% and Mo: 0.2 or 0.25%
47XX - Ni: 1.05%, Cr: 0.45% and Mo: 0.2 or 0.35%
48XX - Ni: 3.5% and Mo: 0.25%
51XX - Cr: 0.8, 0.88, 0.93, 0.95 or 1.0%
51XXX - Cr: 1.03%
52XXX - Cr: 1.45%
61XX - Cr: 0.6 or 0.95% and V: 0.13% min or 0.15% min
86XX - Ni: 0.55%, Cr: 0.50% and Mo: 0.20%
87XX - Ni: 0.55%, Cr: 0.50% and Mo: 0.25%
88XX - Ni: 0.55%, Cr: 0.50% and Mo: 0.35%
92XX - Si: 2.0% or Si: 1.40% and Cr: 0.70%
50BXX - Cr: 0.28 or 0.50%
51BXX - Cr: 0.80%
81BXX - Ni: 0.30%, Cr: 0.45% and Mo: 0.12%
94BXX - Ni: 0.45%, Cr: 0.40% and Mo: 0.12%

Additional letters and numbers following the numbers used to designate stainless steels according to AISI means:
xxxL - Low carbon content< 0.03%
xxxS - Normal carbon content< 0.08%
xxxN - Added nitrogen
xxxLN - Low carbon content< 0.03% + добавлен азот
xxxF - Increased content of sulfur and phosphorus
xxxSe - Added selenium
xxxB - Added silicon
xxxH - Extended carbon range
xxxCu - Added copper

Examples:
Steel 304 belongs to the austenitic class, the carbon content in it< 0.08%. В то же время в стали 304 L carbon total< 0.03%, а в стали 304 H carbon is defined in the range 0.04 - 0.10%. The specified steel, in addition, can be alloyed with nitrogen (then its name will be 304 N) or copper ( 304 Cu).
In steel 410 , belonging to the martensitic - ferritic class, the carbon content<< 0.15%, а в стали 410 S- carbon< 0.08%. В стали 430 F unlike steel 430 increased content of sulfur and phosphorus, and in steel 430 F Se added selenium as well.

ASTM designation system:

The designation of steels in the ASTM system includes:

• letter A, meaning that we are talking about black metal;
• serial number of the ASTM normative document (standard);
• the actual designation of the steel grade.

Usually, the American system of notation for physical quantities is adopted in ASTM standards. In the same case, if the standard provides a metric notation system, after its number, the letter M... ASTM standards, as a rule, determine not only the chemical composition of steel, but also a complete list of requirements for metal products. To designate the actual steel grades and determine their chemical composition, both the own ASTM designation system can be used (in this case, the chemical composition of steels and their marking is determined directly in the standard), and other designation systems, for example AISI - for bars, wire, billets, etc. others, or ACI - for stainless steel castings.

Examples:
A 516 / A 516M - 90 Grade 70 Here A defines that it is a black metal; 516 is the serial number of the ASTM standard ( 516M- this is the same standard, but in the metric notation system); 90 - year of publication of the standard; Grade 70- steel grade. In this case, we use our own ASTM steel designation system, here 70 determines the minimum tensile strength of steel during tensile tests (in ksi, which is about 485 MPa).
A 276 Type 304 L... This standard uses the designation of the steel grade in the AISI system - 304 L.
A 351 Grade CF8M... The ACI notation is used here: first letter C means that the steel belongs to the group of corrosion-resistant, 8 - determines the average carbon content in it (0.08%), M- means that molybdenum has been added to the steel.
A 335 / A 335M grade P22; A 213 / A 213M grade T22; A 336 / A 336M class F22... These examples use proprietary ASTM steels. The first letters mean that the steel is intended for the production of pipes ( P or T) or forgings ( F).
A 269 grade TP304... A combined notation system is used here. Letters TP determine that the steel is intended for the production of pipes, 304 is the designation for steel in the AISI system.

Universal notation system UNS:

UNS is a universal designation system for metals and alloys. It was created in 1975 with the aim of unifying the various designation systems used in the United States. According to UNS, steel designations consist of a letter identifying a group of steels and five numbers.
The UNS system is the easiest to classify AISI steels. For structural and alloy steels belonging to the group G, the first four digits of the name are the designation of the steel in the AISI system, the last digit replaces the letters that occur in the AISI designations. So letters B and L, meaning that the steel is alloyed with boron or lead, correspond to the numbers 1 and 4 , and the letter E, meaning that the steel is smelted in an electric furnace, - the number 6 .
AISI stainless steels start with the letter S and include the AISI steel designation (first three digits) and two additional numbers corresponding to the additional letters in the AISI designation.

Steel designations in the UNS system:
Dxxxxx - Steels with prescribed mechanical properties
Gxxxxx - AISI carbon and alloy steels (excluding tool steels)
Hxxxxx - The same, but for hardenable steels
Jxxxxx - Cast steel
Kxxxxx - Steels not included in the AISI system
Sxxxxx - Heat and corrosion resistant stainless steels
Txxxxx - Tool steels
Wxxxxx - Consumables

Additional letters and numbers following the numbers used to designate stainless steels according to UNS mean:
xxx01 - Low carbon content< 0.03%
xxx08 - Normal carbon content< 0.08%
xxx09 - Extended range of carbon content
xxx15 - Added silicon
xxx20 - Increased content of sulfur and phosphorus
xxx23 - Added selenium
xxx30 - Added copper
xxx51 - Added nitrogen
xxx53 - Low carbon content< 0.03% + добавлен азот

Examples:
Carbon steel 1045 has a designation in the system UNS G 10450, and alloy steel 4032 - G 40320.
Steel 51B60 doped with boron is called in the system UNS G 51601 and steel 15L48 alloyed with lead - G 15484.
Stainless steels are designated: 304 - S 30400, 304 L - S 30401, 304 H - S 30409, but 304 Cu - S 30430.

steel grade			Analogues in US standards
CIS countries GOST	Euronorms
P0 M2 SF10-MP
P2 M10 K8-MP
R6 M5 K5-MP
R6 M5 F3-MP
R6 M5 F4-MP
R6 M5 F3 K8-MP
R10 M4 F3 K10-MP
R6 M5 F3 K9-MP
R12 M6 F5-MP
R12 F4 K5-MP
R12 F5 K5-MP

Structural steel:

steel grade			Analogues in US standards
CIS countries GOST	Euronorms

Basic assortment of stainless steel grades:

CIS (GOST)	Euronorms (EN)	Germany (DIN)	USA (AISI)
03 X17 H13 M2		X2 CrNiMo 17-12-2
03 X17 N14 M3		X2 CrNiMo 18-4-3
03 X18 N10 T-U
06 ХН28 МДТ		X3 NiCrCuMoTi 27-23
08 X17 H13 M2		X5CrNiMo 17-13-3
08 X17 N13 M2 T		X6 CrNiMoTi 17-12-2
		X6 CrNiTi 18-10
20 X25 N20 C2		X56 CrNiSi 25-20
03 X19 H13 M3
02 X18 M2 BT
02 X28 N30 MDB		X1 NiCrMoCu 31-27-4
03 X17 N13 AM3		X2 CrNiMoN 17-13-3
03 X22 H5 AM2		X2 CrNiMoN 22-5-3
03 X24 N13 G2 S
08 X16 N13 M2 B		X1 CrNiMoNb 17-12-2
08 X18 N14 M2 B	1.4583 X10 CrNiMoNb	X10 CrNiMoNb 18-12
		X8 СrNiAlTi 20-20
		X3 CrnImOn 27-5-2
		X6 CrNiMoNb 17-12-2
		X12 CrMnNiN 18-9-5

Bearing steel:

steel grade			Analogues in US standards
CIS countries GOST	Euronorms

Spring steel:

steel grade			Analogues in US standards
CIS countries GOST	Euronorms

Heat resistant steel:

steel grade			Analogues in US standards
CIS countries GOST	Euronorms

Correspondence between domestic and foreign standards for steel and pipes

Steel standards

Germany		European Union	ISO-standard	England	France	Italy	Russia
DIN 17200 SEW 550 SEW 555	heat-treated steel				NFA 35-552 EN 10083	UNI 7845 UNI 7874	GOST 4543-71
	case-hardened steel						GOST 4543-71
	hot rolled steel for annealed springs
	spring wire and steel tape of rustless steel
	ball bearing / trolley steel
	temperature and high temperature material grade for screws and nuts						GOST 5632-72
	forging and rolled or forged steel bar of temperature, weldable steel		ISO 2604/1 ISO / TR 4956
	tool steel including high-speed steel						GOST 1435 GOST 19265 GOST 5950
DIN 17440 SEW 400				BS 970/1 BS 1554-81 BS 1502-82 BS 1503-89		UNI 6900 UNI 6901	GOST 5632-72
	rustless steel for medical equipment
	rustless steel for surgical implant
	valve material grade						GOST 5632-72
	non-magnetic steel
SEW 470 DIN 17145	heat-resistant steel			BS 1554-81 BS 970/1		UNI 6900 UNI 6901	GOST 5632-72
	constructional steel

1.4301 is the standard for austenitic stainless steels due to its good corrosion resistance, ease of shaping and workmanship, combined with its aesthetic appearance in polished, ground and ground conditions.

Standard	EN 10028-7 - Flat-rolled steel for work under pressure. Part 7: Stainless steels EN 10088-1 - Stainless steels. Part 1: List of stainless steels EN 10088-2 - Stainless steels. Part 2: technical delivery conditions for general purpose corrosion-resistant steel sheets and strips 10088-3 - Stainless steels. Part 3. Technical delivery conditions for semi-finished products, rods, wire rod, drawn wire, profiles and products with improved surface finish made of corrosion-resistant steels for general use; EN 10088-4 - Stainless steel - Part 4: Technical delivery conditions for sheet plate and / or strip of corrosion-resistant steels for construction purposes EN 10088-5 - Stainless steels. Part 5. Technical delivery conditions for bars, wire rod, drawn wire, profiles and products with improved surface finish made of corrosion-resistant steels for construction EN 10151 - Stainless steel strips for springs - Technical delivery conditions EN 10216-5 - Seamless steel pipes for pressure purposes. Technical delivery conditions. Part 5. Stainless steel pipes EN 10217-7 - Welded steel pipes for pressure purposes. Technical delivery conditions. Part 7. Stainless steel tubes EN 10222-5 - Steel forgings for pressure vessels. Part 5. Martensitic, austenitic and austenitic-ferritic stainless steels EN 10250-4 - Open-die forging steel blanks for general use. Part 4. Stainless steels EN 10263-5 - Steel bars, strips and wires for cold heading and cold extrusion. Part 5. Basic delivery conditions for stainless steel EN 10264-4 - Steel wire and wire products. Part 4. Stainless steel wire EN 10269 - Steels and nickel alloys for fasteners used at high and / or low temperatures EN 10270-3 - Specification for steel wire for mechanical springs. Part 3. Stainless steel wire EN 10272 - Stainless steel rods for pressure service EN 10296-2 - Welded round steel pipes for mechanical and general technical use. Technical delivery conditions. Part 2. Stainless steels EN 10297-2 - Seamless round steel pipes for mechanical engineering and general technical purposes. Technical delivery conditions. Part 2. Stainless steels EN 10312 - Stainless welded pipes for the supply of aqueous liquids, including drinking water. Technical delivery conditions
Rental	Pipe, rod, bar, wire rod, profile
Other names	International (UNS)		S30400
	Commercial		Acidur 4567

Since 1.4301 is not resistant to intergranular corrosion in the welded state, 1.4307 should be mentioned if welding of large sections is required and no post-weld solution annealing treatment can be performed. Surface condition plays an important role in corrosion resistance. These steels, with polished surfaces, have a much higher corrosion resistance compared to coarser surfaces on the same material.

Chemical composition in% of steel X5CrNi18-10

The specific S value is determined depending on the required properties:
- for machining S 0.15 - 0.30
- for weldability S 0.008 - 0.030
- for polishing S< 0,015

Mechanical properties for grade X5CrNi18-10 (X5CrNi18-10)

EN 10028-7, EN 10088-2, EN 10088-4, EN 10312
Assortment	Thickness, mm, max	Yield strength, R 0,2 , MPa, min	Yield strength, R 1,0 , MPa, min	m , MPa	Oelongation,%, min (longitudinal and transverse specimens) at thickness
					< 3 мм	≥ 3 mm
Cold rolled strip	8	230	260	540 - 750	45	45
Hot rolled sheet	13,5	210	250	520 - 720	45	45
Hot rolled strip	75	210	250	520 - 720	45	45

EN 10250-4, EN 10272 (thickness ≤400)
Thickness, mm	Yield strength, R 0,2 , MPa, min	Yield strength, R 1,0 , MPa, min	m , MPa	Elongation,%, (transverse samples), min	Work of impact energy KV 2, J, min
					Longitudinal samples	Transverse samples
≤250		225	500 - 700	35	100	60

Solid solution treatment:
- temperature 1000 - 1100 ° C
- cooling: water or air

Heat treatment:
+ A - softening annealing
+ AT - treatment for solid solution

Surface quality:
+ C - cold deformation
+ LC - smooth rolling
+ PE - after stripping

EN 10264-4
Diameter (d), mm	Ultimate tensile strength, MPa, min (NT)
d ≤ 0.20	2050
0,20 < d ≤ 0,30	2000
0,30 < d ≤ 0,40	1950
0,40 < d ≤ 0,50	1900
0,50 < d ≤ 0,65	1850
0,65 < d ≤ 0,80	1800
0,80 < d ≤ 1,00	1750
1,00 < d ≤ 1,25	1700
1,25 < d ≤ 1,50	1650
1,50 < d ≤ 1,75	1600
1,75 < d ≤ 2,00	1550
2,00 < d ≤ 2,50	1500
2,50 < d ≤ 3,00	1450

EN 10270-3
Diameter (d), mm	Ultimate tensile strength, MPa, max
	NS	Hs
d ≤ 0.20	2000	2150
0,20 < d ≤ 0,30	1975	2050
0,30 < d ≤ 0,40	1925	2050
0,40 < d ≤ 0,50	1900	1950
0,50 < d ≤ 0,65	1850	1950
0,65 < d ≤ 0,80	1800	1850
0,80 < d ≤ 1,00	1775	1850
1,00 < d ≤ 1,25	1725	1750
1,25 < d ≤ 1,50	1675	1750
1,50 < d ≤ 1,75	1625	1650
1,75 < d ≤ 2,00	1575	1650
2,00 < d ≤ 2,50	1525	1550
2,50 < d ≤ 3,00	1475	1550
3,00 < d ≤ 3,50	1425	1450
3,50 < d ≤ 4,25	1400	1450
4,25 < d ≤ 5,00	1350	1350
5,00 < d ≤ 6,00	1300	1350
6,00 < d ≤ 7,00	1250	1300
7,00 < d ≤ 8,50	1200	1300
8,50 < d ≤ 10,00	1175	1250

EN 10088-3 (1C, 1E, 1D, 1X, 1G and 2D), EN 10088-5 (1C, 1E, 1D, 1X, 1G and 2D)
Thickness, mm	Hardness HBW, max	Yield strength, R 0,2 , MPa, min	Yield strength, R 1,0 , MPa, min	Ultimate tensile strength R m , MPa
					Longitudinal samples	Transverse samples
≤160	215	190	225	500 - 700	45	-
> 160≤ 250 (EN 10088-3, EN 10088-5) > 160 ≤400 (EN 10272)	215	190	225	500 - 700	-	35

Hot deformation: temperature 1200 - 900 ° C, air cooling
Solution treatment: temperature 1000 - 1100 ° C, cooling in water, in air

EN 10088-3 (2H, 2B, 2G and 2P), EN 10088-5 (2H, 2B, 2G and 2P)
Thickness, mm (t)	Yield strength, R 0,2 , MPa, min	Ultimate tensile strength R m, MPa	Elongation,%, min		Impact work KV 2, J, min
			Longitudinal samples	Transverse samples	Longitudinal samples	Transverse samples
≤ 10	400	600 - 950	25	-	-	-
10 < t ≤ 16	400	600 - 950	25	-	-	-
16 < t ≤ 40	190	600 - 850	30	-	100	-
40 < t ≤ 63	190	580 - 850	30	-	100	-
63 < t ≤ 160	190	500 - 700	45	-	100	-
160 < t ≤ 250	190	500 - 700	-	35	-	60

Ultimate tensile strength of wire with a diameter of ≥ 0.05 mm under 2H conditions

EN 10088-3
Ultimate tensile strength, MPa
+ C500	+ C600	+ C700	+ C800	+ C900	+ C1000	+ C1100	+ C1200	+ C1400	+ C1600	+ C1800
500-700	600-800	700-900	800-1000	900-1100	1000-1250	1100-1350	1200-1450	1400-1700	1600-1900	1800-2100

Mechanical properties at room temperature of annealed wire in 2D state

EN 10088-3 (2D)
Thickness, mm (t)	Ultimate tensile strength R m , MPa	Elongation,%, min
0,05< t ≤0,10	1100	20
0,10< t ≤0,20	1050	20
0,20< t ≤0,50	1000	30
0,50< t ≤1,00	950	30
1,00< t ≤3,00	900	30
3,00< t ≤5,00	850	35
5,00< t ≤16,00	800	35

Mechanical properties for rods at room temperature of steels in the hardened (2H) state

Heat treatment before subsequent deformation
- Treatment for solid solution: 1020 - 1100 ° C
- Quenching in water, air or gas (cooling must be fast enough)
Hot deformation before post-processing
- temperature 1100 - 850 ° С
- cooling in air or in a gas environment

Elevated temperature tests

Temperature, ° C	EN 10269 (+ AT)		EN 10088-3, EN 10088-5, EN 10216-5, EN 10272
	Yield strength, min, R p0.2 , MPa		Yield strength, min, R p0.2 , MPa	Yield strength, min, R p0.2 , MPa	Ultimate tensile strength, min, Rm, MPa (EN 10272)
50	177	480	180 (EN 10216-5)	218 (EN 10216-5)	-
100	155	450	155	190	450
150	140	420	140	170	420
200	127	400	127	155	400
250	118	390;	118	145	390
300	110	380	110	135	380
350	104	380	104	129	380
400	98	380	98	125	380
450	95	375	95	122	370
500	92	260	92	120	360
550	90	335	90	120	330
600	-	300	-	-	-

Temperature, ° C	EN 10088-2, EN 10088-4, EN 10028-7, EN 10217-7, EN 10222-5, EN 10312
	Yield strength, min, R p0.2 , MPa	Yield strength, min., R p1,0, min, MPa
50	190 (EN 10028-7), 180 (EN 10217-7)	228 (EN 10028-7), 218 (EN 10217-7)
100	157	191
150	142	172
200	127	157
250	118	145
300	110	135
350	104	129
400	98	125
450	95	122
500	92	120
550	90	120

Physical properties

Density of steel (weight) X5CrNi18-10- 7.9 g / cm 3

Technological properties

Weldability
According to ISO / TR 20172	Group 8.1

The closest equivalents (analogs) of steel X5CrNi18-10

Corrosion resistant

Due to the moderate carbon content of 1.4301, this grade of stainless steel is susceptible to sensitization. The formation of chromium carbides and associated chromium-plated regions that form around these deposits makes this class of steel susceptible to intergranular corrosion. Although there is no danger of intergranular corrosion in the state (solution annealed), intergranular corrosion may occur after welding or high temperature processing. 1.4301 is resistant to corrosion in most environments with low chloride and salt concentrations. 1.4301 is not recommended for applications where it comes in contact with seawater and is not recommended for use in swimming pools.

Welding

1.4301 can be welded with or without filler. If the use of filler is required, it is recommended to use Novonit 4316 (AISI 308L). Maximum spacing temperature 200 ° C. Post-weld heat treatment is not required.

Forging

1.4301 is typically heated between 1150 ° C and 1180 ° C to allow forging between 1180 ° C and 950 ° C. Forging is followed by air cooling or water quenching when there is no danger of distortion.

Treatment

The following cutting parameters are suggested as a guideline when machining the NIRO-CUT 4301 using hard metal cutting tools.