Metal cutting machine tool using the method of cutting the metal into machine parts of the machine, it is the machine of the machine, we call it the precision cnc machining
In our country machine tool industry, machine tool size is different, the number of production is different, for medium and small machine tool generally for mass production: large and heavy machine tool for single or small batch production. General machine tool condition such as load bearing, impact and lubrication conditions, etc., is better than cars, tractors and heavy machinery.
Part is the support of the whole machine tool, its accuracy is high, so the focus of this paper is about the thermal treatment characteristics of machine parts, generally attributed to the following points:
(1) simple general use of non - alloy (Tan Su) structural steel and alloy structural steel. A small number of parts, such as steel, hardened steel, hardened steel and bearing steel, etc..
(2) partially hardened and surface hardened parts more there are many machine parts require only local surface has high wear resistance, except for salt bath furnace local hardening and adopted by a small number of parts, most of the parts by local surface quenching method, such as induction heating and laser heating, a super audio heating hardened.
(3) without using salt bath furnace is used for heating cycle oxidation furnace in most parts of the. Vacuum furnace or in gas carburizing furnace in the injection of kerosene to generate a protective atmosphere.
(4) precision parts are required to have a high dimensional stability and are usually arranged in a working procedure for one or more times.
(5) most of the steel parts must be after pre heat treatment, such as steel castings, forgings and rolled steel, etc., must after annealing, normalizing or quenching and tempering treatment pre heat treatment, to improve its strength, eliminate defects and improve the machining process performance: but also for the final heat treatment do good organization and preparation, reducing the heat treatment deformation.
(6) the majority of the design of the machine tool parts with low temperature chemical heat treatment is considered as rigid, and the heat treatment requirements become small, the wear resistance is high and the stability is good. So low temperature chemical heat treatment process, such as nitriding, nitrogen and carbon, is widely used.