Problems Connected with Reclamation of Worn Parts by the Metal-spraying Process

Abstract

In times of peace the salvaging of worn parts is not usually a major problem confronting the mechanical engineer. Every consideration is given to new materials and to novel designs, but except for those engaged on works maintenance, the returning of old parts to service has not in the past received enough attention from professional engineers. In war time, however, the repair of damaged material becomes a national duty.

Although metal spraying by the wire process has become more widely known during the past two decades, the number of engineers who would feel competent to judge its suitability for any repair is comparatively small. The object of the present paper is to describe certain matters of interest to engineers in connexion with this form of salvage. It is not proposed to give details of metal spraying tools or pistols, as descriptions of these may be consulted in the technical press (Rollason, Turner, and Budgen 1939).† For the same reason an account of the many parts normally repaired by this method (Ballard 1942; Ballard, Fairbairn, and Pilkington 1942) is omitted. Metal spraying is being used commercially to a very large and increasing extent for reclamation work. To assist engineers faced with the problem of repairing a worn part, the author has arranged the paper in the form of answers to the following questions: (a) Is metal spraying a suitable method of reclamation? (b) If so, how must the work be prepared for spraying? (c) What method of spraying and which metal should be used? (d) What finish is necessary?