... as per requirements 4.OEM/ODM YIYAN hardness indenter'YIYAN' produces hardness testing diamond indenters according to ... standard hardness tester, measuring materials have quenching, surface harden steel, steel, quenching and tempering, annealing cold hard castings, malleable ... pieces, hard alloy, aluminum alloy and bearing steel, hardening thin plate, etc various materials.2. Because ...