A precise straightening method for keeping appearance color consistency after crankshaft ion nitriding

Abstract

The invention provides a precise straightening method for maintaining appearance color consistency after crankshaft ion nitriding. The method comprises the following steps of measuring the middle mainhigh point of the crankshaft firstly, a connecting rod with the same direction as the middle-main high-point direction is found out; a tool is installed between the two side walls of the connecting rod in the same direction as the middle main high-point direction of the crankshaft, two side walls of the connecting rod are opened outwards through screwing bolts and two inclined iron, so that the middle main high point is reduced to a target range; and the crankshaft and the straightening tool are used as a whole to enter the furnace for ion nitriding. According to the precise straightening method, the tool is simple to manufacture, surface cracks cannot be generated, accurate straightening can be realized, the appearance color of the crankshaft can be kept consistent, and the required physical and chemical properties are met.

Description

technical field [0001] The invention relates to a precise straightening method for maintaining the consistency of appearance color after ion nitriding of a crankshaft, and belongs to the technical field of engine crankshaft correction. Background technique [0002] In the heat treatment industry, for crankshafts with out-of-tolerance runout after ion nitriding, cold straightening is usually carried out by external pressure. However, due to the thin and brittle nitriding layer and the high pressure required for straightening, the straightened After the crankshaft is tested non-destructively, surface cracks often appear. Another commonly used method is thermal straightening, but the operation is cumbersome and difficult, and there are also potential safety hazards. With the increasing requirements of domestic and foreign customers, some crankshafts require that the runout value after ion nitriding be ≤0.03mm, and the alignment is more difficult, and the requirements for the a...

AI Technical Summary

Problems solved by technology

[0002] In the heat treatment industry, for crankshafts with out-of-tolerance runout after ion nitriding, cold straightening is usually carried out by external pressure. However, due to the thin and brittle nitriding layer and the high pressure required for straightening, the straightened The crankshaft is non-destructively tested and often has surface cracks

Another commonly used method is thermal alignment, but the operation is cumbersome and difficult, and there are also potential safety hazards

With the increasing requirements of domestic and foreign customers, some crankshafts require that the runout value after ion nitriding be ≤0.03mm, and the difficulty of straightening is higher, and the requirements for the appearance and color of the crankshaft are consistent. The above-mentioned methods can no longer meet the technical requirements.

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