Water expansion forming process for vehicle universal joints

Abstract

The invention discloses a water expansion forming process for vehicle universal joints. The process is characterized by comprising the following steps: (1) raw materials-carbon steel pipes are cut asneeded sizes; and burrs at two ends are removed; (2) the carbon steel pipes are annealed at a temperature of 450-600 DEG C to reach the surface hardness HRB of 30-40; (3) the carbon steel pipes are put in a water expansion mold; the mold is tightly pressed by a water expansion machine; meanwhile, booster cylinders at two ends are pushed into punches; saponification liquid with pressure of 16 MPa is injected for primary water expansion formation; the water expansion forming parameters are as follows: the water expansion machine applies the pressure of 120 tonnages to a main cylinder; the pressure is lower than 24 MPa; the output pressure is higher than 18 MPa; the output water pressure of left and right side cylinders is 20-28 MPa; the displacements of the left and right punches are 43 mm;the water cylinder capacity is higher than 1.5 L; and the water supply pressure is lower than 4 MPa; and (4) semi-finished products are annealed again after water expansion by the procedures; the annealing temperature is 450-600 DEG C; and the hardness HRB is 34-36.

Description

technical field [0001] The invention relates to the field of water-expansion molding, in particular to a water-expansion molding process for universal joints used in automobiles. Background technique [0002] The universal joint for automobile is an important part of the automobile, and because its working part is the main transmission force-bearing part, it has high requirements for the strength, stiffness and fatigue resistance of the product. Therefore, in production, the materials and The process has high requirements. In the existing technology, the production of universal joints for automobiles generally adopts precision casting. Since precision casting belongs to thermal processing, the metallographic structure of the raw materials will be greatly changed after thermal processing. The total strength and stiffness will be reduced, so it must go through multiple processing and multiple heat treatment processes to meet the requirements of use. There is another processing...

AI Technical Summary

Problems solved by technology

[0002] The universal joint for automobile is an important part of the automobile, and because its working part is the main transmission force-bearing part, it has high requirements for the strength, stiffness and fatigue resistance of the product. Therefore, in production, the materials and The process has high requirements. In the existing technology, the production of universal joints for automobiles generally adopts precision casting. Since precision casting belongs to thermal processing, the metallographic structure of the raw materials will be greatly changed after thermal processing. The total strength and stiffness will be reduced, so it must go through multiple processing and multiple heat treatment processes to meet the requirements of use. There is another processing method, which is the use of forging molding process, which is currently used more often. Because it is cold working, it has little effect on the metallographic structure of the material, so the production process on the universal joint is widely used, but the disadvantage of this kind of processing is that the production efficiency is low, and the surface quality is poor, the finish is not good, and the surface is uneven. , so it is easy to accumulate oil stains and other corrosive acrobatics in these uneven places. Since it is generally made of ordinary carbon steel, it often has serious rust defects. Try to use surface spraying to reduce this defect. However, for such an important part as the universal joint, it has a great influence on the quality of the product, and it is formed by forging. Since the middle part is a solid product and the weight is heavy, it cannot meet the current requirements for lightweight automobiles.