Heat treating method of coupler terminal pin hole, coupler and flame heating gun head

Abstract

The invention provides a heat treatment method for tail pinholes of car couplers. The method comprises the following steps of using flame to heat an unconnected zone on the arc-surfaced top wall of a tail pinhole till the surface temperature of the unconnected zone reaches over 900 DEG C and then rapidly cooling the unconnected zone to room temperature, so as to form unconnected hardened layers on the arc surface of the tail pinhole. As the slow heating speed of flame is beneficial to heat diffusion when the unconnected zone of an arc top surface is heated, a large hardness gradient can be prevented from being formed in a heat treatment layer, so as to prevent great internal stress from being produced on joints of the hardened layers and transition layers. Therefore, the heat treatment method provided by the invention can prevent the occurrence of cracks at the same time while improving the wear resistance of the tail pinhole.

Description

technical field [0001] The invention relates to the field of heat treatment, in particular to a heat treatment method for a tail pin hole of a coupler, a coupler and a flame heating gun head. Background technique [0002] In railway vehicles, the coupler is used to transmit traction and impact force, so as to realize the mutual involvement between the locomotive and the vehicle or the vehicle and the vehicle, and keep a certain distance between the vehicles. [0003] figure 1 It is a schematic diagram of a truck coupler, which is successively composed of three parts: a coupler head 11, a coupler body 12, and a coupler tail 13, and connecting parts (not shown) such as a knuckle tongue are housed in the coupler head. The coupler tail 13 is provided with a vertical flat keyhole, also known as a coupler tail pin hole, for inserting the coupler tail pin so as to be connected with the coupler tail frame. In order to realize hooking or unhooking, the coupler has three states such...

AI Technical Summary

Problems solved by technology

[0006] Although induction hardening has the advantages of fast heating and high work efficiency, it has disadvantages that are difficult to overcome when it is used for surface treatment of coupler pin holes.

Due to the unique shape of the coupler tail pin hole, when induction heating is used, the heating rate of the workpiece is too fast, and the heat is too late to be transmitted to the surroundings of the workpiece, and a large temperature gradient is generated inside it, so a large hardness gradient is formed on the workpiece. As a result, there is a large internal stress at the junction of the hardened layer and the transition layer, resulting in a large number of cracks on the surface of the coupler pin hole after induction hardening, which reduces the service life of the coupler

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