1. Standard system

Stainless steel wire standards are mainly based on two systems:

German-French-Russian system: It is characterized by knowing the ingredients when you see the brand. China's stainless steel representation method applies the method of the former Soviet Union, and countries belonging to this system include Italy, Spain, Poland, Romania, the European Union and India.

The American-British-Japanese system: its characteristic is that the steel number is concise, clear, and easy to remember, and the organizational structure of the steel can be known by seeing the number. Countries and regions that belong to this system include Canada, Brazil, Australia, South Africa, South Korea and Taiwan Province of China.

1.1 German-French-Russian Standard System

1.1.1 Common steel grades in German-French-Russian standard system (Table 2)

Table 2 Common steel grades in German-French-Russian standard system

1.1.2 Representation of Chinese steel grades

1Cr18Ni9: The average nickel content is 9%, the average chromium content is 18%, and the carbon percentage content*10 (ie 0.1%).

①The first number before the grade is 10 times the carbon percentage. If it is 0 C≤0.08% 00 C≤0.03%

②The number after the main element indicates the percentage content of the element. If the element content is less than 1.5%, do not write the number, and write 2 after the element greater than 1.5 and less than 2.5.

③The trace elements such as Ti, Nb, Al, and N in the steel should be written out.

④For free-cutting steel, add "Y" before the steel number.

⑤Add "L" after the steel number to indicate cold drawing; add "Q" to indicate light drawing; add "R" to indicate soft state.  

1.1.3 Element symbols of the German-French-Russian standard system (Table 3)

Table 3 Element symbols of German-French-Russian standard system

1.1.4 Other instructions

The X before the German steel number means high alloy steel.

The Z before the French steel number stands for high-alloy steel.  

1.2 US-UK-Japan standard system

1.2.1 Commonly used grades in the US-UK-Japan standard system (Table 4)

Table 4 Commonly used grades in the US-UK-Japan standard system

1.2.2 AISI American Iron and Steel Institute stainless steel representation method

①The stainless steel grade consists of 3 digits: the first digit indicates the type of steel, and the second and third digits indicate the serial number of the steel.

2XX chromium-manganese-nickel series austenitic steel

3XX chromium-nickel series austenitic steel

4XX high chromium ferritic and martensitic steels

5XX low chromium martensitic steel

6XX Precipitation Hardening Steel

② Later, AISI made uniform regulations on metal and alloy grades:

SXXXXX heat-resistant stainless steel

NXXXXX Nickel and Nickel-Based Alloys

JXXXXX all kinds of cast steel

S1XXXX Precipitation Hardening Steel

S2XXXX Nickel Austenitic Steel

S3XXXX chromium-nickel austenitic steel

S4XXXX high chromium stainless steel

S5XXXX heat resistant steel

The grade (UNS system) consists of 5 digits, the first three digits are consistent with the original grade, and the last two digits are used to distinguish grades with the same main components, different individual components or with special elements.

1.2.3 Other instructions

Before the Japanese brand: SUS-special purpose stainless steel

SUH—Special Purpose Heat Resistant Steel

SW - wire or steel wire

After the Japanese brand: -W: stainless steel wire

―WP: Stainless steel wire for spring

―WS: Stainless steel wire for cold heading

―Y: Stainless steel wire for welding wire

Before the Korean brand: STS - special purpose stainless steel

STR—Special Purpose Refractory Steel

2. Comparison of commonly used grades

In the domestic stainless steel market, due to the large number of imported products from Taiwan Province, South Korea and Japan, the southern market has been accustomed to purchasing stainless steel according to the US-UK-Japan grades. To open up the market, it is necessary to be familiar with and master the US-UK-Japan standard system grades.

2.1 Austenitic steels

301 1Cr17Ni7 as spring

302 1Cr18Ni9 as spring

302HQ 0Cr18Ni9Cu3 Good cold heading performance

303 Y1Cr18Ni9 for precision shaft

304 0Cr18Ni9 general steel grade

304M 0Cr18Ni9 Ni 9.0%-10.0% for rivets

304H 0Cr18Ni9 C 0.05%-0.08% high strength

304N 0Cr18Ni9N improves strength

304HC 0Cr18Ni9Cu2 reduces magnetic properties, improves corrosion resistance, and is used as rivets

304L 00Cr18Ni10

305 1Cr18Ni12 non-magnetic

308 0Cr21Ni12 for welding

309 0Cr24Ni13 for welding

310 0Cr25Ni20 heat resistance, corrosion resistance, stable use temperature 1100 ℃

314 0Cr25Ni20Si2 heat resistance, corrosion resistance, stable use temperature 1150 ℃

316 0Cr17Ni12Mo2 with Mo added to resist chloride ion corrosion

316L 00Cr17Ni14Mo2 hydrogen sulfide corrosion resistance

317 0Cr17Ni13Mo3 resistant to body (human body) liquid corrosion, used as surgical implants

317L 00Cr19Ni13Mo3

321 0Cr18Ni11Ti Titanium-stabilized carbon

347 0Cr18Ni9Nb Add Niobium Stabilized Carbon

384 0Cr16Ni18 non-magnetic stainless steel

201 1Cr17Mn6Ni5N for precision shaft

202 1Cr18Mn8Ni5N for spirit shaft

204Cu 1Cr17Mn6Ni5Cu3N general purpose stainless steel

205 2Cr17Mn15Ni2N high strength

3.2 Ferritic steel

The price is cheap, the corrosion resistance is good, and the cold upsetting performance is good.

405 0Cr13 409 0Cr12Ti

410L 00Cr12 429 0Cr15

430 0Cr17 434 1Cr17Mo

430F Y1Cr17 has a good finish and is used as a shaft.

3.3 Martensitic steel

For tool industry:

410 1Cr13

414 1Cr13Ni2

416 Y1Cr13

420J1 2Cr13

420J2 3Cr13

420F Y3Cr13

431 1Cr17Ni2 (2Cr16Ni2) has good nitric acid resistance. The bearing industry produces measuring tools, cutting tools and rolling elements:

440A 7Cr17Mo 440B 8Cr17Mo

440C 9Cr18Mo (11Cr17Mo European and American steel grade composition)

2.4 Precipitation hardening steel

630 0Cr17Ni4Cu4Nb high strength steel

631 0Cr17Ni7Al for spring

632 0Cr15Ni7Mo2Al for spring

3. National (regional) stainless steel wire standards

3.1 American stainless steel wire standard

The United States is the country with the most complete varieties of stainless steel wires. There are nearly 100 different grades of austenite, ferrite and martensite in the 6 ASTM standards. Knowing American standards has certain inspiration for the formulation and use of Chinese standards.

ASTM A580N-95a Stainless Steel Wire

ASTM A313M-95 Stainless Steel Spring Wire

ASTM A478-95a Chrome-Nickel Stainless Steel Braided Wire

ASTM A493-95 Stainless Steel Wire and Rod for Cold Upsetting

ASTM A492-95 Steel wire for stainless rope

ASTM A581-95b Free Cutting Stainless Steel Wire and Rod

AWS A5.22-82 Cr and CrNi Corrosion Resistant Steel Flux Cored Wire

AWS A5.4-84 Chromium and Chromium Nickel Corrosion Resistant Steel Electrodes

3.2 Stainless Steel Wire Standard of Taiwan Province of China

CNS G3067-86 stainless steel rod

CNS G3199-88 Heat Resistant Steel Bar

CNS G3077-86 Stainless Steel Wire Rod

CNS G3076-86 Stainless Steel Wire

CNS G3189-87 Stainless steel wire for cold upsetting

CNS G3190-88 Stainless steel wire for welding

CNS G3161-86 Stainless steel wire for spring

3.3 Japanese stainless steel wire standard

JIS G4303-98 stainless steel rod

JIS G4311-91 Heat-resistant steel bar

JIS G4309-94 stainless steel wire

JIS G4314-94 Stainless steel wire for spring

JIS G4315-94 Stainless steel wire for cold upsetting

JIS T6103-94 Dental stainless steel wire

JIS Z3321-89 Stainless Steel Electrode

JIS Z3321-85 Stainless steel electrodes and wires

JIS Z3324-88 Stainless Steel Coated Electrode and Flux

3.4 Stainless steel wire standards of other countries and organizations

DIN 17224-84 (Germany)

BS 1554-1990 (UK)

P-Г 0CT18143-72 (former Soviet Union)

NF A35-577-90 (France)

UNI 6901-71 (Italy)

KS D3703-1992 (Korea)

SS 142332 (1991) (Sweden)

NS 14480 (84) (Norway)

IS 6528-72 (India)

CSA G110.3 (Canada)

EN 151 (1986) (EU)

ISO 6931-1-1994 (International Standardization)

4. Introduction to current standards in my country

4.1 GB/T1220-92 stainless steel bar

This is a basic standard, and the chemical composition of stainless steel wire all implements this standard. Among them: austenite (A) 33 steel grades, ferrite (F) 7 steel grades, martensite (M) 18 steel grades, dual-phase steel (A+F) 3 steel grades

Austenitic steel: It is a non-magnetic structure and has good cold working properties. The corrosion resistance is better than 430 and other martensitic steels, and the heat resistance is better. Disadvantages: expensive, difficult thermal deformation, slightly poor intergranular corrosion and stress corrosion performance.

Most of the austenitic steels are composed of Cr-Ni, such as 304, 316, 1Cr18Ni9Ti.

18-8 type steel When Ni<8%, ferrite appears, and when the nickel content is low to a certain level, it becomes A+F dual-phase steel. Ferrite is magnetic, 100% austenite is non-magnetic. When the nickel content in 1Cr18Ni9Ti is 8%, the ferrite content is 5%-15%. In order to reduce the nickel content of 304M in steel by 9%-10%. The ferrite content is reduced to 2%-3%.

Ferritic steel: 430 (0Cr17) ​​is a typical ferritic steel. Good heat resistance, low price, and good cold working (cold upsetting) performance. Grain coarsening is irreversible at high temperature, and the cold workability of steel deteriorates due to improper heat treatment process.

Martensitic steel: can be quenched, tempered and hardened, with improved strength and wear resistance. But the corrosion resistance is poor.

The standard provides some data for the mechanical properties of each steel grade, and the steel grade can be selected based on these data when using.

Standard evolution process: YB1059→GB1220-75→GB1220-84→GB/T1220-92

4.2 GB/T1221-92 heat-resistant steel bar

Martensitic valve steel 4Cr9Si2, 4Cr10Si2Mo, 8Cr20Si2Ni

Austenitic valve steel 5Cr21Mn9Ni4N (21-4N), 2Cr21Ni12N

Standard evolution process: YB11-59→GB1221-75→GB1221-84→GB/T1221-92

4.3 GB/T4240-93 stainless steel wire

4.3.1 Cold-drawn delivery (L)

Austenite: 316 (0Cr17Ni12Mo), 304 (0Cr18Ni9), 302 (1Cr18Ni9), 304N (0Cr19N)

This type of steel has fast cold work hardening, high strength and slightly poor flexibility, and is used for structural parts, load-bearing frames, pins, shafts and the like. Martensitic steels are not delivered in cold drawn condition.

4.3.2 Light Pulling State Delivery (Q)

Austenitic steel, ferritic steel and martensitic steel can all be delivered in a lightly drawn state. Good strength and toughness, neat material shape, raw materials for deep processing, production of flat, special-shaped wire, shaft wire, tie wire, netting, rivets, nails, frames.

4.3.3 Soft State Delivery (R)

Austenitic steel, ferritic steel, martensitic steel can be delivered in soft state. The soft state finished steel wire has good plasticity, good flexibility and good corrosion resistance. The disadvantage is that the strength is low.

A - solution treatment F, M - annealing delivery

As specified in the polished stainless steel wire standard, the strength is allowed to fluctuate by 10%.

Soft state The strength increases by 8%-10% after straightening.

Cold-drawn state After straightening, the strength decreases, and the magnitude of the decrease is related to the surface reduction rate, and the reduction of the surface reduction rate (high strength) is much lower. The light pull strength does not change much.

Free-cutting steel wire: delivered in a soft state or cold-drawn state, mainly used to make shafts for motor timers and household appliances. The shafts produced have good finish and good dimensional accuracy.

Standard evolution process: YB252-64→YB252-79→GB4240→84→GB/T4240-93

4.4 GB/T4232-93 stainless steel wire for cold upsetting

NL1Cr18Ni9Ti and ML1Cr17Ni2 are old steel grades, mainly used by military units. 304M, 304HC (the largest amount) and 302HQ (for inner hexagon) are new steel grades, which are widely used by the Southern Standard Parts Factory. 316 makes rivets with good corrosion resistance. 305 makes non-magnetic rivets.

When ML1Cr18Ni9Ti requires resistance to intergranular corrosion, the chemical composition Ti/C should be controlled to be greater than or equal to 5.5. The steel wire is difficult to produce, mainly due to pitting, intergranular corrosion, and unstable size.

The disadvantage of ML1Cr17Ni2 is that the surface is prone to cracks.

New steel grade: 304HC (0Cr18Ni9Cu2), 302HQ (ML0Cr18Ni9Cu3)

304M→304HC→302HQ→305→384

Weak magnetic → weak magnetic → no magnetic → no magnetic → absolutely no magnetic

Price: low→high Cold working performance: poor→good

Standard evolution process: GB4232-84→GB/T4232-93

4.5 GJB 3320-98 and YB (T) 11-83 stainless steel spring wire

4.5.1 GJB 3320-98 0Cr17Ni7Al Group A is equivalent to the US military standard MIL-W-4460788. Group B is formulated with reference to DIN 17224. Group A Φ2.0-3.0mm high strength, B group Φ0.2-7.0mm low strength.

4.5.2 1Cr18Ni9 is equivalent to BS-S205 British aviation standard

4.5.3 The stainless steel wire of YB(T)11-83 spring is equivalent to JIS 314. This standard is different from the national military standard in chemical composition. For example, the national military standard requires electroslag remelting to be smelted. P and S elements are strictly controlled, while YB (T) 11-83 can use electric furnace steel, and the content of nickel and chromium in the steel can be slightly higher.

GJB714-89 was formulated when Dalian Steel Works and the Ministry of Ordnance Industry jointly developed stainless steel wire, and can be replaced by GJB3320-98.

4.6 YB/5091-93 and YB/T5092-96 stainless welding wire

YB/5091-93 and YB/T5092-96 are formulated on the basis of GB 1300-77 with reference to JIS Z3321 and JIS Z3221. YB/5091-93 "Stainless Steel Rods and Wires for Inert Gas Shielded Welding" (formerly GB 4233-84), including 11 pieces of A, 1 piece of F, and 1 piece of M. The specification of steel rod is Φ1.0-5.0mm, and the specification of steel wire is Φ0.8-2.4mm, which is a standard with strong advanced consciousness.

YB/T5092-96 "Stainless Steel Wire for Welding" is formulated by combining the actual usage in my country with the international general situation. The standard includes 16 A, 2 F, and 3 M.

Standard evolution process

: YB 199-63→GB 1300-77→GB 4242-84→YB/T5092-93→YB/T5092-96.

Regarding stainless welding wire, from the perspective of domestic and foreign standards, there is a big gap between my country's product standards and production methods and foreign countries. Foreign product standards generally stipulate that the welding wire should be tested for weldability, weld mechanical properties and corrosion resistance, but there is no such requirement in my country's welding wire standards. Foreign welding wires are mostly supplied as finished products. Welding wire manufacturers also produce various fluxes. They are also engaged in welding process research. While supplying welding rods, they also provide users with reasonable welding processes. my country's welding wire production, welding rod production and welding process research are three independent systems, and there is no stable coordination mechanism among the three, which is very unfavorable to the progress of welding technology.

4.7 Other Standards

YB/T096-1997 high carbon chromium stainless steel wire: including 440A, 440B, 440C, 9Cr18 and 9Cr18Mo five high carbon chromium martensitic steels, annealed delivery σb630-830MPa.

YB/T5219-93 medical suture needle steel wire: steel number 3Cr13, 4Cr13, actual size Φ0.22-2.05mm, heat treatment delivery σb490-685MPa, light pulling delivery σb≤885MPa.

Standard evolution process: YB 549-65→GB 10563-89→YB/T5219-93.

YB/T5183-93 Special-shaped steel wire for automobile body accessories: 1Cr18Ni9 dome-shaped steel wire for windshield wipers, cold drawn σb1080-1275MPa.

Standard evolution process: GB8708-88→YB/T5183-93.

GB/T4234-94 Stainless steel for surgical implants: including rods, wires, plates, and belts, with a total of 3 steel grades (00Cr18Ni13Mo3, 00Cr18Ni14Mo3, 00Cr18Ni15Mo3N), to evaluate the microstructure, hardness, inclusions, and corrosion resistance.

Standard evolution process: GB 4234-84→GB/T4234-94.

GB/T9944-88 stainless steel wire rope: assessment of the breaking force of the whole rope, steel wire grade and tensile strength are mutually agreed upon.

YB/T5250-93 Non-magnetic stainless steel 0Cr16Ni14 standard for electric vacuum devices includes hot-rolled bars and flats, cold-rolled strips and wires, and wires are delivered in hard or soft states, and the specification range is Φ0.1-18.0mm , the main assessment of civil magnetic rate μ100, μ200≤1.005Gs/Oe, remanence Br1000≤0.15Gs.

Standard evolution process: GBn189-82→YB/5250-93

5. A few points of view

(1) A stainless steel wire system based on two stainless steel rod (wire rod) standards and four stainless steel wire standards as the pillars has been successfully constructed, but the content of the six standards needs to be coordinated and updated to adapt to domestic production and use. The status quo is in line with the world trend.

①Wire rod standard: Necessary adjustments should be made to the size range, deviation, unit weight, delivery status, grade and other items according to the actual domestic production.

②Stainless steel wire (GB/T4240): The delivery status item can add matte, bright, polished, nickel-plated and other states, 304 should be refined, and 200 series grades should be introduced.

③Cold top steel wire: Add domestic general grades 304M, 304HC, 429, 434, etc. The magnetic performance and cold top performance of different levels should be listed as assessment indicators.

④Spring: To achieve serialization, the smelting method should be diversified. Added 200 series grades.

⑤Welding wire: The steam protection welding wire is delivered with a standard spool, and the welding rod is consistent with GB/T9803-1995. The welding performance test is added, and the welding process and other reference materials are provided.

(2) According to the development level of stainless steel wire production and use in my country, some professional standards should be formulated in time, such as: screens, stainless steel wires for textiles, precision shafts, stainless steel wires for rolling elements, stainless steel filaments, free-cutting stainless steel wires, and medical equipment. Stainless steel wire, guide the use of stainless steel wire in the right direction.