Steel Standard Comparison, CNS, JIS, AISI, ASTM, DIN

The first critical step for precise metal processing is to understand the characteristic of alloy steel or material. Before Tien-I move on to mass production for OEM/ODM metal part, Tien-I team will focus on understanding the customer's need. Then we can make the recommendation for alloy steel, after considering cost efficiency for alloy steel processing.  

That's why the interntional standard for alloy steel is the basic knowledge for this business. Here we will offer general introduction: 

1. Chinese National Standard (CNS)

CNS is shortening of Chinese National Standard, the coding of stainless material for CNS mainly based on CNS 109 G1001 (Publish: 1947.03, Edited 1996.03). In principle, it combined by following three parts:

The first part is material, the stainless material mainly states as S (Steel) or F (Ferrum)

The second parts is two kinds of representation:

a. Means standard name or product use: Commonly use - P: Plate、T: Tube 、U: Use、W: Wire、F: Forging、C: Casting example: S P CC：Plate, steel plate (cold) SUP：Use Spring, Spring Steel

b. Stainless material used for structure (including structural carbon steel or alloy steel), mainly represent as alloy element or carton content (structural carbon steel). When means carbon content, usually represent as 100 multiple of carbon content.

Example: SCM420：Cr-Mo steel，the 420th steel. S25C：carton steel, carbon content 0.25%

The third part is type number、the lowest resistant strength or yield strength for that material. Usually it represents as 3 digital number if it's the lowest resistant strength or the lowest yield strength. Example: SCM 420 means the material of type number 420 for CR-MO steel.

2. Japanese Industrial Standard (JIS)

JIS is shortening of Japanese Industrial Standard , mainly divided two types for the steel material number:

(1) General Mechanical structure carbon steel. The material number is same as CNS first type presentation. (Example) S30C means carbon content 0.30% of mechanical structure carbon steel

(2) Other use of Carbon steel and alloy steel: This kind of material code divided three parts.

1st part: Material - Steel means S, Iron means F, other non-steel see table 11-

2nd part: Steel specification or use,

example: K means Tool steel、TB means boiler pipe、PC2 means cold-rolled steel

3rd part: Type of steel material, represent as 1、2、3 If needed, the notation can add material processing method、heat treatment .. etc in the back. Processing method such as D (Drawing)、G(Grinding)、T(Turning)、Ex(Extruded). Mostly, the heat treatment is notated in the back of the metal symbol or insert "-" between two items.

Example: SK2：The second type of Carbon Tool Steel SKS11：The 11th of cutting tool steel SUH301：The 301 of heat-resistant steel SUS301-1/2H：The 301 of stainless steel, 1/2 hard material

3. American Iron and Steel Institute - The Society of Automotive Engineers (AISI-SAE)

AISI and SAE set up a classification of steel material in 1941, to clarify and notated by 4 or 5 digital number.

The 1st digit: means type of steel, example: Nickel steel is 2 and Tungsten steel is 7.

The 2nd digit: The main alloy percentile, 0 means no other ally element.

The 3rd 、4th digit: means carbon content

Example: SAE1045：Carbon steel carbon content 0.45, equal with CNS S45C SAE4140：CR-MO steel carbon content 0.40, equal with JIS SCM440

4. American Society for Testing and Materials / American Society of Mechanical Engineers ASTM (ASME)

ASTM is very widely used material specification, its characters mainly focus on product feature and performance. ATSM notation is based on letter + symbol, and combined with years. ASME use lots of ASTM specification, and notated pre-S.

Example: ASTM A36-77a which A 36 - 77 a means (Steel) (Structural use) (by 1977) (first edit) In addition: ASTM E8 means tensile test specification

5. Deutsches Institut fur Normung e.V (DIN)

DIN is not English but shortening of Germany: Deutsch Industriell Norm. The Chinese Steel specification is DIN 17006 and additional information is added in DIN 17007. In 1974 changed to ISO, and replaced as EURONORM 27-74. The characters is described by English letter and numbers, letter is specified type of steel, smelting method, alloy materials, processing condition; the digital is specified steel material, carbon content, tensile strength and main alloy's element multiple.

(1) carbon steel Carbon Steel generally notated as carbon element and its carbon content, such as C60 means 0.6% carbon steel content. And also means tensile strength and others notation,

example: St50 means tensile strength 50kg/mm2 structural carbon steel ; CK40 means carbon steel which content low Phosphorus and sulfur, and its tensile strength is 40kg/mm2

(2) Superior steel and low alloy steel Mainly use alloy element and content as notation, but in the 3rd part content, to avoid decimal point, the value is already multiplied by a fixed multiple, and show as integer, so when calculating the actual amount by the numbers, it must be divided by the multiples. 1st part: carbon content 2nd part: alloy element type 3rd part: alloy element content

Example: Carbon content 0.34% chromium content 1% steel, show as 34Cr4 Therefore, 13CrV53 means carbon content 0.13%, chromium content 5/4=1.25%, Vanadium content 3/10=0.3%

(3) High ally steel If "X" is added in front of the notation, since the alloy element content have been high, so it will be directly represented instead of multiplied in multiples. (like stated previously, high alloy steel usually mean alloy content is over 8% of steel material).

Example: Carbon content 0.12% stainless steel, chromium content 18%, Nickel content 8% show as X12CrNi18 8. 
Similarly, X10CrNi1810 means carbon content 0.10% high alloy steel, chromium 18%, Nickel 10. If need to further notated its character, some English alphabet can added in the front or in the back of the notation.

Example: M A St42 6 N (1) (2) (3) (4) (5) (3) is the main notation, (1)(2)(4)(5) separately mean: smelting method、products features、ensure the performance category、heat treatment and so on。

(4) Cast iron、Cast steel Pre-marked G means general cast, and add other alphabet to indicate its type, following's notation same as number of steel. 

Example: GS-C30 is cast steel, carbon content 0.30% G-X120Mn12 means carbon content 1.20% cast iron, Manganese content 12%