SUS316 stainless steel hardness grade and test method

Hardness is one of the key indicators for evaluating the wear resistance and strength of SUS316 stainless steel. Below is an overview of its common hardness levels and testing methods.

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Common Hardness Levels of SUS316 Stainless Steel

1. Annealed Condition (Soft State) Hardness

In the standard annealed condition (1050°C water quenched), SUS316 stainless steel typically exhibits relatively low hardness:

Brinell Hardness (HBW): ≤ 217 HB

Rockwell Hardness (HRB): ≤ 95 HRB

Vickers Hardness (HV): typically below 200 HV

This makes it highly suitable for applications that require cold forming and excellent ductility.

2. Work-Hardened Condition (After Cold Working)

After cold working, the hardness of SUS316 stainless steel increases significantly:

Cold-rolled hardness ranges between 200–300 HV

Heavily deformed areas can even exceed 300 HV

Such a condition is ideal for components like stainless steel springs, fasteners, and wear-resistant parts.

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Hardness Testing Methods for SUS316 Stainless Steel

SUS316 stainless steel can be tested using several international standard hardness methods, including the following:

1. Brinell Hardness (HB)

Application: Suitable for large, thick sections or bulk material hardness testing

Test Method: A steel or tungsten carbide ball is pressed into the sample under a standard load, and the diameter of the indentation is measured

Common Standards: ASTM E10 / GB/T 231

2. Rockwell Hardness (HRB/HRC)

Application: Commonly used for small to medium-sized components or to compare hardness after heat treatment

Test Method: A steel ball or diamond cone is pressed into the material using a minor and major load, and the depth of the indentation is measured

Common Scales for SUS316: HRB (annealed), HRC (work-hardened)

Common Standards: ASTM E18 / GB/T 230

3. Vickers Hardness (HV)

Application: Suitable for precise parts, small samples, or micro-area hardness measurements

Test Method: A diamond pyramid-shaped indenter is pressed into the material; the diagonals of the indentation are measured

Features: Ideal for evaluating surface treatments or thin sections

Common Standards: ASTM E92 / GB/T 4340

4. Micro Vickers Hardness

Application: Used for weld zones, microstructures, coatings, and films

Advantage: Enables accurate analysis of hardness variations across different surface regions of the metal