| 摘要 |
<p>Machine parts, esp. i.c. engine components, which can be highly loaded and have a ductile high strength core and a harder, wear resistant and corrosion resistant case, are produced from a steel of compsn. up to 0.8% C, up to 3% Mn, less than 0.6% Si, up to 0.3% V, balance Fe by soln. heat treating, at 860-1000 deg.C and simultaneously boriding to form a Fe2B case of up to several tenths of a millimetre thickness, and then cooling at a rate of 2-50 deg.C/min. The process is useful in the prodn. of i.c. engine piston crowns, piston ring carriers, cylinder heads, cylinder bushes, crankshafts, camshafts, cam discs or gear wheels. Components having surfaces resistant to high temp. frictional wear and corrosive attack and having cores which are fatigue resistant are produced by a method which is less expensive than conventional methods.</p> |
