易切削钢切削机理的试验研究

An Experimental Investigation of Cutting Mechanism for Free-Cutting Steel

通过对Ca-S复合易切削钢的切削刀具、切屑、快速落刀后切屑上积屑瘤以及钢中夹杂物的观察分析,证明了Ca-S复合易切削钢中,由于存在低熔点夹杂物,使其在高速切削过程中,在前、后刀面上形成一极薄的“Belag”薄膜,此薄膜对刀具有润滑作用,故可减少刀具与切屑的摩擦,削弱刀具材料扩散到切屑上的活性,从而大大提高了刀具寿命。在中、低速切削时,由于MnS的断屑与减摩作用,也改善了切削条件,提高刀具寿命。因此,Ca-S复合易切削钢是一种适合高、中、低各种切削速度的优良易切削钢。

Based on the observation and analysis of cutting tools, cutting chips and lumps on the quickly falled cutting chips when cutting Ca-S compound free-cutting steel, as well as inclusions in the ste el, it is proved that because there are low-melting point inclusions existed in the Ca-S compound free-cutting steel, a very thin film so called 'Belag' formed on front and rear cutter surfaces during high-speed cutting process, this thin film helps lubricate the cutters, therefore friction between cutters and chips can be reduced, the activity of diffusing cutter material into cutting chips is weakened, after all the cutter life is evidently prolonged. During medium or low speed cutting processes because MnS has chip-breaking and antifriction properties, this steel may also improve cutting conditions and prolong cutter life. Hence the Ca-S compound free-cutting steel is a fine steel suitale for high, medium and low speed cutting processes.