Micro-defects on machined carbon steel surfaces

Contrary to the evidence of stylus instruments, the residual roughness of machined 0.35% carbon steel surfaces changes as a function of cutting speed. The origin of the microdefects, observed by electron microscopy and, with one exception, unresolved by conventional roughness measurement techniques, is thought not to be any malfunction of the machining process, but inherent in the process of surface formation. This paper describes micro-defects considered relevant to contacting surfaces and indicates that cutting speed selection for finish machining of tribological components based on conventional roughness measurements is questionable.