A method for local softening of high-strength alloy steel carburized parts

Abstract

The invention relates to the field of local annealing heat treatment of carburized parts and specifically relates to a local softening method of high-strength alloy steel carburized parts. The local softening method can be applied to manufacturing the carburized parts having different requirements on the hardness of the high-strength steel. A carburized locking pin is locally heated by use of fused salt in a salt-bath furnace; the locking pin is made of martensitic steel 16Cr3NiWMoVNbE; an annealing heat-protective fixture is adopted for performing heat protection on the carburized surface of the locking pin part, and the local annealing part is heated till a temperature above 600 DEG C for softening. The local softening method of the high-strength alloy steel carburized parts is capable of reducing the hardness of the flaring positions of the parts and preventing the parts from cracking in the flaring process under the condition of guaranteeing the hardness of the carburized surfaces. According to the local softening method, the method of rapid heating annealing by use of protective salt bath is adopted for performing annealing treatment on the gear locking pin, so that the high strength of the carburized surface and the base body of the part can be prevented from reduction, and the hardness of the portion needing to be deformed can be reduced, and as a result, the cracking problem in the flaring deformation process of the part is solved.

Description

technical field [0001] The invention relates to the field of local annealing heat treatment of carburized parts, in particular to a method for local softening of high-strength alloy steel carburized parts, which can be used to manufacture carburized parts with different hardness requirements of high-strength alloy steel. Background technique [0002] Such as figure 1 As shown, the carburized locking pin 1 is installed on the transmission gear, and the carburized locking pin 1 part is made of 16Cr3NiWMoVNbE alloy martensitic steel, and is subjected to carburizing + quenching + low temperature tempering treatment, and partial For flaring, because the hardness of the parts is high in the low-temperature tempering state (the core part is above 44HRC), cracks will occur during flaring, resulting in the scrapping of the parts. In order to prevent the parts from being scrapped due to cracks during the flaring process, it is necessary to perform local annealing treatment on the fla...

AI Technical Summary

Problems solved by technology

If high-frequency high-stress heating is used, it is difficult to process such a small induction coil, and the heat-affected zone of induction heating is relatively large. Annealing the carburized part that should not be annealed will affect the performance of the locking pin 1 part.

If the electrolyte heating and annealing method is used, the annealing part of the locking pin 1 reaches high temperature instantly, and the locking pin 1 part is subsequently quenched with salt water, which cannot achieve the purpose of annealing

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