Effects of deep cryogenic treatment on the wear development of H13A tungsten carbide inserts when machining AISI 1045 steel

In this study, the effects of deep cryogenic treatment (93 K) on the surface and sub-surface wear development of H13A cobalt-bonded tungsten carbide cutting inserts during the wet machining of AISI 1045 steel were investigated. Cutting inserts were subjected to short periods (171–553 s) of turning at cutting speeds of 50–140 m/min, during which time mass measurements were taken and the worn edges were imaged and scanned, by optical microscopy and light interferometry, at regular intervals. Sections were taken following machining so that sub-surface features could be observed by scanning electron microscopy. It was determined that cryogenic treatment resulted in a 9.2 % increase in hardness and an increase in abrasive wear resistance, although microstructural changes and sub-surface behaviours suggested a corresponding decrease in toughness may have occurred.