Titanium plate and titanium alloy drawing formability of cylindrical parts deep drawing

The common deformation modes of titanium sheet can be summarized as deep drawing, stretching, flanging, bending and composite forming. However, it is difficult to make a typical test piece if a single drawing deformation method is used. So the actual use of the test is composite deformation. In addition, the test is bound to bring mold structure and operation process factors, so the evaluation of sheet drawing is a lot of complex problems. Based on the limit drawing coefficient K(LDR), many evaluation methods have been put forward from analysis, test and statistics, and many problems have been solved. But more commonly used steel and aluminum as the main object, so it must be modified and supplemented for titanium and titanium alloy.

The drawing test method for cylindrical parts was proposed by Swift in 1940, which measured the limit drawing coefficient K value by progressively increasing the wool, and was recommended as the international standard by the International Deep drawing Research Institute in 1967. This method tested the drawing performance of a large number of steel, aluminum and copper sheet materials.

When used in titanium, especially α and α+β titanium alloys, the main problems are as follows:

A. Bending fracture occurs at the four corners of the punch;

B. Wrinkling occurs at the rounded corners of the concave die.

This is the titanium alloy bending and wrinkle resistance is not good, can not fully explain its deep drawing. For example, TC4, TA7 plate deep drawing is poor or impossible. They are tested for drawing by Englhardt or the maximum drawing force test, and bending damage is more serious because the material is required to adhere completely to the punch and then the drawing force is determined.

It is suggested that the punch fillet should be enlarged, and anti-wrinkle measures should be taken at the concave die fillet and graphite lubricant should be used for deep drawing test of titanium alloy.