The expander unit of the 50m~3/h oxygen generator produced by our factory has a kind of part called roller. The material is 45 steel, the quenching hardness is HRC58-62, the inner hole size is φ20_0~(+0.025)mm, and the surface roughness is required to be R0.8～0.4. Through multiple production tests, the surface roughness of the workpiece can not meet the requirements. , has not been qualified for many years
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