Boro-carburizing microalloying method of shearer cutter

Abstract

The invention relates to a borocarbon diffusion micro alloying method for the pick of a coal mining machine. Alloy steel 35CrMo is adopted as pick material, and the method comprises the following processing steps that: step 1, acid cleaning; step 2, carburization, titanizing and manganizing treatment: carburizer and lanthana powder are carried out and evenly stirred and sent into an infiltration box; titanium powder and manganese power are adopted to coat on the cutting part at the tooth tops of the pick that is then vertically put into the infiltration box which is compacted and sealed; then the infiltration box is sent into a heating furnace, the temperature is rised to 650 DEG C + / - 10 DEG C, is kept for 1.5 to 2.5 hours, then continuously rised to 910 DEG C + / - 10 DEG C and is kept for 8 to 10 hours; then the temperature is lowered to 850 DEG C + / - 10 DEG C and is kept for 1.5 to 2.5 hours and continuously lowered to less than 800 DEG C and taken out of the furnace; the taken-out infiltration box is cooled to room temperature and opened; step3, boronizing, tungstenizing and chromizing treatment; step 4, salt-bath treatment; step 5, annealing treatment; step 6, tempering treatment; step 7, shot-peening treatment. The method of the invention is capable of improving the intensity, hardness and high-temperature abrasion resistance at the tooth tops of the pick of the coal mining machine and causes the handle of the pick to be difficult to break.

Description

technical field [0001] The invention relates to a shearer pick, in particular to a boron-carburized micro-alloyed shearer pick method. It belongs to the technical field of coal machinery manufacturing. Background technique [0002] The pick is an important part of the shearer, and it is also the most consuming and easily damaged part on the shearer. Therefore, its strength, hardness and wear resistance will directly affect the service life of the pick. [0003] CN200710156941.4 discloses a "Shearer Pick Surface Treatment Process". It uses 35CrMoV as the base material, after forging, gold processing and shaping, and then the following surface treatment: [0004] (1) Carburizing treatment [0005] Put the pick vertically in the infiltration box filled with carbon powder, compact, cover and seal; [0006] Put the infiltration box in the heating trolley furnace, raise the temperature to 650°C, keep it warm for 4-5 hours, then heat it up to 900°C, keep it warm for 8-9 hours,...

AI Technical Summary

Problems solved by technology

[0018] 1. Pure carbon powder is used for carburizing treatment. The infiltration speed of carbon powder is slow, and the structure of carburized layer is not dense enough; The combination of the material and the boronizing layer on the surface is not strong enough, and the problem of carburizing on the surface of the pick and boronizing layer falling off is prone to occur

[0019] 2. Boronizing, molybdenum and chromium treatment boronizing layer structure is not dense enough, strength and high temperature wear resistance are not high enough

[0020] 3. During the use of the shearer pick, another failure mode is the breakage of the pick shank. This is because during boronizing, only the head of the pick is boronized in the boron-carburizing alloy, and for the Pick shank, only annealing treatment, this heat treatment will cause decarburization or carburization of the pick shank, resulting in excessive carbon content

[0021] 4. In the boronizing process, the holding time for boronizing at 900°C is 8-9 hours, and the boronizing time is unreasonable. More than 6 hours will not only effectively increase the boronizing layer, but also bring waste, and too long Time will lead to coarse grains, increased boronizing layer fragmentation, and easy peeling, which will affect the quality of the final workpiece