How to inspect the hardness of investment castings?

We all know one of the most important standard of investment casting quality is the hardness.The hardness value of investment castings will be a factor that affects machining of investment castings.

1.Brinell hardness:it is used to test the hardness of investment castings,forging parts,hot rolled billet,annealing pieces,ect.Testing range>HB450.

2.Rocknell hardness:HRA is mainly used to test pieces of high hardness and the hardness of inspected parts should be higher than HRC67.Like products tungsten carbide, nitriding steel,ect,the measuring range>70.HRC is often used measure steel made parts(like carbon steel,alloy steel,ect)after quenching or tempering.Measuring rangeHRC20~67.

3.Vickers hardness:Used to measure the hardness of thin parts and steel parts.Also could be used to test case hardening parts with surface treatment like carburization,carbonitriding,nitridation,ect.