Conversion-rolling of titanium/steel bonded composite

Claim 2

In a process for conversion-rolling at elevated temperature a substantially flat, metallurgically bonded composite product comprising a titanium layer and a steel layer bonded together by a substantially diffusionless wavy interfacial bond containing, by area, at least about 70 percent direct titanium-to-steel bonding with any solidified melt at the interface present in discrete regions between areas of direct titanium-to-steel bonding, the improvement which comprises a. heating said composite product to a temperature in the range of 1,500* to 1,550* F.; b. commencing rolling the heated composite product at a temperature in said range and continuing rolling until the thickness of the product is no greater than about one-tenth of its prerolling thickness, the product being rolled in two different directions substantially normal to one another, the amount of thickness reduction accomplished in said two directions being sufficient to achieve a thickness reduction ratio of not less than 1.5/1 in the initial rolling direction and not less than 3/1 in the final rolling direction, and the total time the product is maintained at a temperature in the range of 1,500* to 1,550* F. being no more than 4 hours; and thereafter c. heating the rolled product at a temperature in the range of about from 1,200* to 1,300* F. for a period of at least about 0.5 hour.

Claim 3

A process of claim 3 wherein Step (a) is performed twice and Step (b) in two stages, a stage of Step (b) following each Step (a), and the rolling in the final stage being continued until the thickness of the product is no greater than one-third of the thickness it had when entering that stage.

Claim 4

A process of claim 4 wherein the direction of rolling in the final stage of Step (b) is substantially normal to the direction of rolling in the first stage thereof.