Question regarding Brinell/Vickers Hardness Test

[ecstacynight]

Vickers Hardness Test
Question : For Vickers Hardness Test to test the material hardness we uses different force [kfg], Why do we need to use different force like 1kgf and 5kgf?

Brinell Hardness Test
Question : Pure Copper : Require force is 62.5
Steel : Require force is 187.5
Why is there a change in the force require?

 

[Astronuc]

Vickers Hardness Test
Question : For Vickers Hardness Test to test the material hardness we uses different force [kfg], Why do we need to use different force like 1kgf and 5kgf?

Brinell Hardness Test
Question : Pure Copper : Require force is 62.5
Steel : Require force is 187.5
Why is there a change in the force require?

Pure metals are generally softer than alloys. Pure copper would be softer than steel, but steel is a rather general category, and there is a range or spectrum of hardness.

We use different loading forces depending on the softness of the materials. Softer materials require less force to achieve a certain deformation, while harder materials resist deformation and require a higher load/force to achieve a certain deformation. Each test is based on a certain geometry of the indentation within some limited range.

Note there are several hardness tests, and they can be correlated.

Rockwell Hardness Test
Stanley P. Rockwell invented the Rockwell hardness test. He was a metallurgist for a large ball bearing company and he wanted a fast non-destructive way to determine if the heat treatment process they were doing on the bearing races was successful. The only hardness tests he had available at time were Vickers, Brinell and Scleroscope. The Vickers test was too time consuming, Brinell indents were too big for his parts and the Scleroscope was difficult to use, especially on his small parts.
. . . .

See - http://www.instron.us/wa/applications/test_types/hardness/default.aspx

 

[ecstacynight]

Thanks that was useful :D