1. Quenched thiab tempered steel Lub hardness test ntawm quenched thiab tempered steel mas siv Rockwell hardness tester HRC nplai.Yog tias cov khoom nyias nyias thiab HRC nplai tsis haum, HRA nplai tuaj yeem siv tau.Yog hais tias cov khoom yog thinner, nto Rockwell hardness nplai HR15N, HR30N, los yog HR45N ...
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