What Is the Difference Between S30408 and 304 Stainless Steel?

There are three differences between S30408 and 304:

1. S30408 is the UNS numerical code of the national standard stainless steel 06Cr19Ni10, while the UNS numerical code of 304 is S30400;

2. The chemical composition content of S30408 is different from that of 304, which is shown in four elements: carbon C, phosphorus P, sulfur S and chromium C;

3. The mechanical properties of S30408 and 304 are slightly different, which is shown in the yield strength.

Which is better, S30408 or 304? What is the difference between S30408 and 304? Which is safer to use in food? Let me elaborate on these three points in detail:

1. Is S30408 the same as 304?

Is stainless steel S30408 304?

S30408 is a mark for one of the austenitic stainless steels according to the UNS numbering system.

S30408 stainless steel is equivalent to 06Cr19Ni10, which is a common stainless steel material.

The corresponding UNS number of 304 is S30400, so S30408 and 304 are not identical.

What Is the Difference Between S30408 and 304 Stainless Steel? 1

2. Origin of S30408

The UNS numbering system specifies 18 numbering series for metals and alloys.

Each UNS number is prefixed by a single letter followed by five Arabic numerals.

In most cases, the letter represents metallicity.

For example, stainless steel is represented by “S”.

304 is the grade code, indicating Cr Ni austenitic 300 series stainless steel.

The percentage of Cr Ni content is different, and the corresponding grade codes are 301, 316, 321, etc.

Therefore, S30408 is the name given by UNS numbering system to stainless steel with specific Cr Ni content percentage.

3. Chemical composition difference between S30408 and 304

Standard name UNS code Grade C Mn P S Si Cr Ni N
American Standard ASTM A240M-15a S30400 304 0.07 2.00 0.045 0.03 0.751 7.5-19.58 8.0-10.5 ..
China standard GB/T24511-2017 S30408 06Cr19Ni10 0.08 2.00 0.035 0.015 0.751 8.0-20.08 8.0-10.5 0.1
Japanese standard JISG4305:2012   SUS304 0.08 2.00 0.045 0.03 1.00 8.0-20.08 8.0-10.5 ..
European Standard EN10028-7:2016   1.4301 0.07 2.00 0.045 0.015 1.00 7.5-19.58 8.0-10.5 0.1

Note: the proportion is a percentage, i.e. “%”; Except for the indicated range, the components listed in the table are the maximum values.

The chemical composition of S30408 and 304 stainless steel is slightly different.

For example, 304 requires lower carbon content, S30,408 requires lower phosphorus and sulfur content, and higher chromium content.

S30408 element content executive standard and 304 material content standard, please refer to S30408 and 304 chemical composition comparison table above.

S30408 and 304 stainless steel are food-grade materials, which meet the national standards for food-grade stainless steel.

In terms of safety, stainless steel S30408 and 304 can be used as kettle, children’s cup, food container and cooker.

4. Differences in mechanical properties between S30408 and 304

Mechanical Properties of Austenitic Steel after Solution Treatment at Room Temperature

Number code Grade Specified plastic extension strength RPo. 2/MPa Specified plastic extension strength RP1.0/MPa Tensile strength Rm/MPa Elongation after fracture A% Hardness value
Not less than Not greater than
S30408 06Cr19Ni10 220 250 520 40 201 92 210

Mechanical Test Requirements

Yield Strength Tensile Strength Elongation in 2 in or 50mm. min Hardness.max
Mpa Mpa % BrinellHBW Rockwell
205 515 40 201 92 HRBW

In terms of mechanical properties, stainless steel S30408 and 304 have little difference.

The yield strength, tensile strength, elongation and hardness of the two can be compared and analyzed by referring to the above table.

Mechanical properties limit the use of materials.

S30408 stainless steel coils are mostly hot rolled. S30408 hot rolled steel has better processing performance and better plasticity than cold rolled steel.

The strength and hardness of 304 cold-rolled stainless steel coil are higher than those of hot-rolled stainless steel coil, but the plasticity is reduced, which weakens the stamping performance.

This article introduces the difference between stainless steel S30408 and 304, hoping to help you decide which is better.

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