PRODUCTION OF PURE NICKEL STRIP BY THE DIRECT-ROLLING PROCESS

Abstract

Results are presented of an investigation into the production of pure nickel strip, 6 in. wide × 0·030 in. thick, from carbonyl-nickel powder, using compacting rolls 7 ? in. in dia., arranged in a horizontal plane. Special reference is made to the factors affecting the quality and output of green strip: roll-gap dimensions, the head of powder above the roll gap, rolling speed, and raw-material properties. It is shown that for a given compacting mill, the thickness of green strip that can be produced is strictly limited and that it becomes progressively more difficult to achieve the limiting thickness with increase in rolling speed. A method of reducing the detrimental effect of high rolling speeds is described.

The continuous sintering and subsequent processing of directly rolled strip, using conventional cold-rolling and annealing plant, are then considered, and the properties of fully processed material are compared with those of strip produced from melted and cast carbonyl-nickel pellet. It is concluded that the direct-rolling process is capable of producing on a commercial basis nickel strip having properties which compare favourably with those of conventionally produced material.