Method for forging large steel shaft forging

Abstract

The invention discloses a method for forging a large steel shaft forging. The method comprises the following steps of: performing cogging, chamfered edge rounding, whole stretching for the first time, whole stretching again, section-by-section forging and the like on a medium carbon steel standard octagon ingot of which the carbon content is 0.3 to 0.4 percent. The step of whole stretching for the first time comprises the following steps of: heating a forged piece to a primary forging temperature; stretching on a forging hammer with a flat anvil; and reaching the deformation rate of 29 to 31 percent at the effective hole welding temperature of over 900 DEG C so as to overcome internal defects of the forged piece. The step of whole stretching again comprises the following steps of: heatingthe forged piece to the primary forging temperature; stretching on the forging hammer with the flat anvil; and reaching the deformation rate of 15 to 20 percent at the final forging temperature of 800 DEG C. And the single-time deformation rate of each section when the section-by-section forging is performed should not be less than 20 percent. The method of the invention effectively overcomes theinternal defects of the material, reduces the material and working time waste, more reasonably distributes the deformation rate of each step, contributes to the reduction of the forging deforming force and realizes ideal material mechanical property.

Description

technical field [0001] The invention relates to a processing method for a steel shaft forging, in particular to a forging process flow for a large steel shaft forging. Background technique [0002] Large-scale shaft forgings generally refer to forgings with a weight of more than five tons. The material of the steel ingot is generally medium carbon steel, and there are inevitably some defects such as looseness and air bubbles in the steel ingot. The existence of these defects will seriously reduce the strength of the part, so in the end These defects are not permitted in acceptable parts. The processing flow of large shaft forgings is generally "forging-rough turning-flaw detection-heat treatment". The purpose of flaw detection is to check whether the above-mentioned defects still exist after the workpiece is forged. If internal defects are found during the flaw detection process, the forging must be re-forged to eliminate internal cracks or holes by thickening, elongating, ...

AI Technical Summary

Problems solved by technology

Although four forgings have been carried out on the large end of the forging, the maximum single deformation is 27%, which is often not enough to eliminate the internal defects of the material, which can be eliminated when the original defect size is small, while the original defect size is larger It is difficult to eliminate when it is large, so once there are still defects after forging, it must be re-forged

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