Method and device for eliminating internal stress of non-quenched and tempered steel automobile engine connecting rod forge piece

Abstract

The invention relates to a method and device for eliminating internal stress through heating annealing, in particular to a method and device for eliminating internal stress of a non-quenched and tempered steel automobile engine connecting rod forge piece. The method includes the steps that firstly, after the temperature in a heating furnace cavity is increased to 350 DEG C to 400 DEG C under the nitrogen protection and the oxygen content is smaller than or equal to 0.2%, the forge piece is heated, heating is conducted for 70-80 min to the temperature of 540 DEG C-560 DEG C, and heat preservation is conducted for 90 min; secondly, cooling is conducted under the nitrogen protection, discharging is carried out after the temperature of lower than 100 DEG C is reached after 50 min, and natural cooling is conducted in air. The device comprises a nitrogen generating device, a drying device, an air compression device and a heat treating device. The heat treating device comprises a furnace body, a partition door, a heat insulation plate, an air inlet pipeline, an air outlet pipeline, a conveying mechanism, a feeding furnace door, a discharging furnace door, a heating device and a control cabinet. According to the method and device for eliminating internal stress of the non-quenched and tempered steel automobile engine connecting rod forge piece, the internal stress can be completely eliminated, a good appearance of the forge piece is maintained, continuous production is achieved, and the working efficiency is improved.

Description

technical field [0001] The invention relates to a method and device for eliminating internal stress by heating annealing, in particular to a method and device for eliminating internal stress of a non-quenched and tempered steel automobile engine connecting rod forging. Background technique [0002] At present, in the forging industry at home and abroad, it is a common problem that the connecting rods of automobile engines (connecting rods made of non-quenched and tempered steel forged and produced by air-cooling technology) are scrapped due to cracking and dislocation problems. The main reason for cracking and dislocation is the internal stress generated by forging, so how to eliminate internal stress has become a problem that every forging enterprise has to face. [0003] The traditional method of eliminating internal stress is: heating the forging to a certain temperature, keeping it warm for a period of time, and then cooling it naturally. There are certain shortcomings ...

AI Technical Summary

Problems solved by technology

There are certain shortcomings and deficiencies in the above method, which are specifically shown as: The surface of the forging will be oxidized during the heating process. After the internal stress is eliminated, the surface needs to be cleaned again, resulting in increased waste and increased costs; The decarburized layer on the surface of the forging is out of tolerance and cannot meet the product requirements

Moreover, the traditional heat treatment equipment used to eliminate internal stress is generally a single-type chamber, and the heating, heat preservation, and cooling are all completed in one chamber, and the work efficiency is low.

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