Precise cold forging formed cam sheet manufacturing method

Abstract

The invention relates to a precise cold forging formed cam sheet manufacturing method. The manufacturing method includes the steps of A, pretreatment, B, cold forging forming and C, thermal treatment, wherein in the step A, a steel wire rod or a steel bar is annealed, drawn and lubricated, so that a first blank suitable for cold upsetting forming is obtained; in the step B, a cam sheet is forged through a horizontal or vertical forging machine, and the cold forging forming step includes an expansion and extrusion procedure. Due to the adoption of the expansion and extrusion technology, acquisition of a ball bearing steel cold forging cam is possible for the first time; compared with the traditional upsetting technology, forging force is greatly reduced, the cold hardening speed is low, cracks are not likely to generate, the service life of a die is greatly prolonged, a metallographic structure can not be changed in the cold forging process, and a surface structure is free of the carbon insufficiency risk; due to the fact that a finally-used outline is obtained through precise extrusion or finishing directly, the outline of the cam does not need to be ground, and equipment investment and part cost are greatly reduced.

Description

technical field [0001] The invention relates to a method for manufacturing a precision cold forging cam piece. Background technique [0002] In recent years, with the enhancement of people's awareness of low-carbon environmental protection, low fuel consumption, no pollution, light weight, and low-cost engine models have attracted more and more attention. In order to reduce automobile exhaust emission pollution, low fuel consumption, and realize high speed and high output power of the engine, many engines adopt a structure with multiple valves, valve timing, and variable valve lift. At the same time, in order to achieve the goal of light weight and low cost of automobiles, the processing of parts should be simplified as much as possible, the weight should be reduced, and the use of materials should be more reasonable without affecting the performance of each part. And with the adoption of engine turbocharging and direct injection technology, the degree of strengthening of t...

AI Technical Summary

Problems solved by technology

The disadvantages of the hot forging process are: 1. Once the temperature exceeds the phase transition temperature, the local structure of the part will be transformed, or even hardened, and there is a risk of cracking

The disadvantages of the warm forging process are: 1. The material needs to be heated, the equipment is more complicated, and the cost is high

2. The operating environment of warm forging is relatively harsh

3. In warm forging, due to the use of induction heating, it is difficult to control the temperature. Under equipment debugging and low speed, the material may be heated beyond the phase transition temperature, and there is a quality risk

However, due to the poor cold deformation plasticity of high-carbon bearing steel or combined steel, it is not easy to form, and the deformation amount is relatively large during the flattening process of relatively large variables (area after deformation-area before deformation / area before deformation>1.5), and there are cracks in forgings risk; and under cold conditions, high-carbon bearing steel or bonded steel has greater cold deformation resistance, so the required deformation pressure is greater, and general cold forging equipment is not enough to meet its forming tonnage

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