The Study On Mechanism Of High-speed Cutting Of High-strength Hardened Steel With Continous CBN Tools

High speed machining technology is an important research direction for the21stcentury manufacturing, it has been widely used in aircraft, automobile and mouldmaking.58SiMn widely used in the weapons industry due to its high strength, highhardness, good hardenability and steady fragmentation performance.58SiMn steel hasthe high hardness and high strength after quenching, so making its workability poor.The traditional cutting only use low cutting speeds and make the cutting efficiency lowand tool wear serious. The whole cubic boron nitride as a new type of super-hard toolmaterial, it has a high hardness, high thermal stability, high chemical stability, highabrasion resistance, difficult to react with the iron-based metal, and othercharacteristics, these make it has a good prospect application in cutting high hardnessferrous materials. In this paper, the mechanism of58SiMn hardened high strength steelduring the high speed cutting with the whole CBN tool was researched. The mainresearch work as follows:(1)The influence of cutting speed, feed rate and cutting depth on the cutting forceduring interrupted turning were researched. The experimental results showed that: thecutting force reduced firstly and when the speed reach a certain the cutting force nolonger reduced, next the cutting force slightly ascended with increasing the cuttingspeed. The cutting force increased with increasing the feed rate and cutting depth.(2)The empirical formula of cutting force during turning58SiMn with the wholeCBN was established by the linear regression analysis.(3)The influence of cutting speed, feed rate and cutting depth on the surfaceroughness were researched. The result showed that: the surface roughness increasedquickly with increasing the feed rate, and decreased firstly next increased withincreasing cutting speed.(4)The influence of cutting speed, feed rate and cutting depth on the tool damage were researched. The result showed that: the major damage form is chipping duringturning58SiMn hardened steel with the PCBN tool. The tool wear result from abrasivewear, diffusion and adhesive wear.