Tham khảo tài liệu 'volume 18 - friction, lubrication, and wear technology part 17', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Table 5 Recommended tool steels for backward extrusion of two parts Total quantity of parts Io be Ntrud d a Mtital to be extruded 5 000 50 000 Punch material Aluminum alloys A2 A2 D2 Carbon steel up Io c A2 D2 M2 b Carburizing grades of alloy Steel A2 M2 b Die material Alum i num alloys Wl c Wl c Carbon steel up to c 01 A2 A2 d Carburizing grades of alloy Steel 01 A2 A2 d Knockout material Aluminum alloys A2 D2 Carbon Steeb up to c and carburizing grades of alloy Steel A2 100 mm Parti Parts Note Where two tool materials arc recommended for the same conditions they are given in ardor of cast lhe less expensive being shown first a Far part I .starling with a solid slug for part 2 starting with part L. In aluminum part 2 can he triads directly from a cylindrical blank b Liquid nitrided c The c grade is recommended d Gas nitrided on the inside diameter only. Source Ref 3 Source Ref 3 The recommendations for dies to extrude these parts from steel are conservative because a D2 punch might achieve a total life of 300 000 pieces with 60 000 between redressings for the dies O1 might achieve 40 000 pieces between redressings and 160 000 total as compared with 70 000 and 200 000 pieces respectively for A2 steel. Because of economic considerations sintered carbide should be considered for punches for long runs over 500 000 parts wherever press and die equipment is rigid enough not to cause breakage of carbide tools. When the wear limit of tools or the part tolerance is narrow or when runs are long and production shutdowns must be avoided carbide is used as insert material in the dies to extrude either steel or aluminum. Die Materials for Sheet Metal Forming The useful performance of a forming die is measured in terms of its wear. Total wear is affected primarily by the length of the production run and the severity of the forming operation. Hence production quantity and severity are the most important factors in selecting die materials for forming. The
