Hardness of Stainless Steel

If the material type or stainless steel grade carbon content percentage you know? hardness test is a simple way to verify that a material has been properly heat treated. Hardness testers such as Rockwell, Brinell, and Vickers can be useful to check metals for actual hardness.

Hardness tests are generally considered nondestructive, hardness testing does leave a small pit in the surface; therefore, hardness tests should not be used on sealing surfaces, fatigue critical parts, load bearing areas,etc., components which will be used in critical applications . These hardness tests provide a convenient means for determining, within reasonable limits, the tensile strength of steel. It has several limitations in that it is not suitable for very soft or very hard stainless steel pipe.

Hardness testing of aluminum alloys should be limited to distinguishing between annealed and heat-treated material of the same aluminum alloy. In hardness testing, the thickness and the edge distance of the specimen being tested are two factors that must be considered to avoid distortion of the metal. Several readings should be taken and the results averaged. In general, the higher the tensile strength, the greater its hardness.

The Shore (Scleroscope) Hardness Test
The Scleroscope test consists of dropping a diamond tipped hammer, which falls inside a glass tube under the force of its own weight from a fixed height, onto the test specimen. The height of the rebound travel of the hammer is measured on a graduated scale.The harder the material, the higher the rebound.

Hardness of Stainless Steel according to ASTM A213

The Knoop indenter has a polished rhombohedral shape with an included longitudinal angle of 172° 30’ and an included transverse angle of 130° 0’. The narrowness of the indenter makes it ideal for testing specimens with steep hardness gradients and coatings. Knoop is a better choice for hardness testing of hard brittle materials.

Jominy Hardenability

The Jominy test involves heating a test specimen of steel 25mm diameter and 100mm long to an austenitising temperature and quenching from one end with a controlled and standardized jet of water. After quenching, the hardness is measured at intervals taken form the quenched end. The hardness gradient along the test surface provides an indication of the material’s hardenability.

The Moh's hardness scale consists of 10 minerals arranged in order from 1 to 10. Diamond is rated as the hardest and is indexed as 10; talc as the softest with index number 1.

Each mineral in the scale will scratch all those below it as follows:

Brinell and Rockwell Hardness Conversion Chart
Hardness Testing General
Brinell Hardness Testing
Rockwell Hardness Testing
Vickers Hardness Testing
Bend Testing
Compression Testing
Tensile Strength Tesing
Yield Strength Testing
Metallographic Test - Metallography Testing
Metallographic Test Report
Intergranular Corrosion
Carbon Low Alloy Steel and Cast Steel Hardness Conversion Table
Rockwell Rockwell Superficial Brinell Vickers Shore Hardness Conversion Table

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