Application of Promising Sparingly Alloyed Steels for Gears of Mobile Machines

Abstract

Examples of the main types of destruction of highly loaded gears in transmissions of automotive and tractor vehicles are given. Their causes are analyzed. It is established that the criterion for the performance of highly stressed gears of transmissions subjected to hardening of chemical heat treatment is a deep contact fatigue of the active surfaces of the teeth. It is shown that to increase the resistance of contact fatigue of gears in transmissions of mobile machines, it is important to ensure high microhardness in the zone of maximum deep contact stresses. The results of the use of traditional and sparingly alloyed steels for highly loaded transmission gears are compared. The advantages of using sparingly alloyed steels are shown. It has been established that the tendency to deform of traditional high alloy steel during heat treatment is 2–4 times higher than that of sparingly alloyed steels. The lifetime of gears made of sparingly alloyed steels is increased by at least 2 times. These steels are recommended for the manufacture of highly stressed gears.

Keywords

• transmission gears
• sparingly alloyed steels
• chemical heat treatment
• cemented layers
• mechanical characteristics
• deformation
• destruction
• resource