MANUFACTURING CLAD PRODUCTS BY SPRAY FORMING

Whilst if has been feasible to spray form clad products for several ye ars, if has been difficult to generate a high integrity metallurgical bond at the interface of the mandrel and the sprayed alloy. Consequent ly, roll preforms have generally been produced in the form of rings wh ich are subsequently fitted to the roll arbor or mandrel. However, a j oint project in progress between Forged Rolls (UK) Ltd, British Rollma kers Corporation, Osprey Metals Ltd and Sheffield University (with par t funding from the UK, Department of Trade and industry under the ''LI NK'' enhanced engineering materials programme) has demonstrated that d irect bonding of roll alloys onto steel arbors can be achieved using a rbor preheating in conjunction with multi-atomisers and other special techniques. The equipment to achieve such results is described, togeth er with an outline of the deposition method. initial metallographic an d mechanical property results are also presented with a comparison mad e between conventionally processed and spray formed roll alloys, where a considerable refinement in the spray formed microstructure is appar ent. These encouraging results have led to the spray forming of narrow , clad hot and Gold strip mill rolls for actual field trials.