论文部分内容阅读
图1所示的圆锥齿轮是拖拉机的重要传动零件,热处理变形影响齿的啮合效果,并对齿轮的使用寿命和拖拉机的噪音发生影响。20CrMnTi钢齿轮要求经渗碳或碳氮共渗后达到下列技术条件:(1)渗层结构与心部组织要符合NJ-39-75部颁标准;(2)表面硬度为HRC58～64,心部硬度为HRC35～47;(3)A面内挠≤0.12mm;(4)A面外挠≤0.08mm;(5)φ127D孔椭圆度≤0.10mm。目前,齿轮一般采用渗碳后缓冷,再加热并进行压力淬火。我厂原采用脉动压床淬火,最佳合格率为90%,最差仅20%左右。为解决圆锥齿轮的淬火变形问题,我们初步总结出制齿——消除应力——预加变形,装在专用挂具上进行碳氮共渗直接淬火的处理工艺。略述如下:
The bevel gear shown in Fig. 1 is an important driving part of the tractor. The deformation of the heat treatment affects the meshing effect of the teeth and affects the service life of the gear and the noise of the tractor. 20CrMnTi steel gear requirements after carburizing or carbonitriding to achieve the following technical conditions: (1) the structure of the infiltration layer and the heart department to comply with the ministerial standards NJ-39-75; (2) the surface hardness of HRC58 ~ 64, the heart Department of hardness HRC35 ~ 47; (3) A surface deflection ≤ 0.12mm; (4) A outer surface deflection ≤ 0.08mm; (5) φ127D hole ovality ≤ 0.10mm. At present, the gear is generally slow cooling after carburizing, then heating and pressure quenching. I plant the original use of pulsating press quenching, the best pass rate of 90%, the worst only about 20%. To solve the problem of bevel gear quenching deformation, we initially concluded that the tooth - to eliminate stress - pre-deformation, mounted on a special hanging on the carbonitriding direct quenching process. Outlined below: