Second Paper: Extrusion of Steel and Titanium

This paper describes the results of forward and backward extrusion tests on steel and titanium specimens at very high impact speeds, using reductions in area of 44 to 86 per cent. The specimens were in all cases of 1-in diameter, 1.5 in long. For the cold forward extrusion of steel, impact speeds over the range 68-310 ft/s were used. Comparison of mean extrusion and work of deformation at these high speeds was made with the values arising at very low speed. Extrusion pressures were minimal in the impact velocity range 40-80 ft/s.Tests using steel billets preheated to temperatures between 300 and 600°C showed no great advantage in preheating above 400°C. This degree of preheating showed considerable advantages over the cold process, in that extrusion pressures were much reduced, product quality was improved, and higher extrusion ratios could be obtained. Limited backward extrusion tests at 66 ft/s proved the feasibility of the process.Gold forward extrusion of titanium at 65 and 167 ft/s was successful onl...