THE ECONOMICS OF STAINLESS-STEEL STRIP PRODUCTION BY ROLL COMPACTION

Abstract

While production of a material by a powder-metallurgy route is often necessary to obtain desired properties, the potential economic advantages of such a method may also be sufficiently attractive to justify development on a large scale. This particularly applies, in some instances, to the production of thin strip by roll compaction.

The economic attraction of the roll-compaction process lies in the combination of the potentially high utilization of material, low processing costs, and modest demands for capital equipment. With certain materials, powder is readily available at a price that enables these advantages to be realized. However, with others, such as mild steel, new techniques of low-cost powder production must be developed to ensure survival of the method.

The more highly alloyed materials, such as stainless steel, generally show a low yield by conventional processing routes and thus the scope for improvement is greater. The addition of alloying elements in the solid state raises certain problems in the case of stainless steel, but the use of conventional melting procedures followed by atomization and subsequent fabrication of the atomized powder may still prove economically attractive.

Calculations based on a hypothetical plant producing 40,000 tons/annum by a production route involving roll compaction, sintering, and cold reduction show that, even if extensive cold reduction and continuous annealing are required, it may still be possible to obtain finished strip at a cost that is lower than that of material produced by conventional processing. Moreover, if hot reduction of the roll-compacted and sintered strip is feasible, then this cost could be further reduced.

Notes

* Manuscript received 9 July 1968. Contribution to a Symposium on “Powder Rolling and Associated New Techniques of Powder Production,” to be held in Swansea on 13 and 14 November 1968.