Tham khảo tài liệu 'machining processes part 2', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 66 Cutting Tool Materials Isostatic pressing Fig. 12 The FULDENS process lor producing tool steel powder. Source Ref 4 Broaching. These fools constitute another major application for P M high-speed tool steels because tool life is often improved when P M steels are used to broach diffi-cult-to-cut materials such as case-hardened steels and superalloys. One application required broaching SIX ball tracks that are used in front-wheel-drive automobiles in constant-velocity joint hubs made of a casehardening steel. Figure 17 shows the join Fin Typical milling cutters made from P M rig. I high-speed tool steels. Courtesy of Speedsteel Inc. hubs and broaching tool used in this application. In this broaching application surface finish and form tolerance requirements are high because subsequent machining is not performed on the ball tracks. In broaching with tools mm in. in diameter and mm in. in length made from low-carbon M35 steel similar lo M4I in chemical composition the total number of hubs machined per tool was 5600. The M35 tools experienced severe Hank wear and developed a large built-up edge which Fin 1 2 Examples of ports manufactured by the FULDENS process. Note the complexify of shapes attainable by this process a Using cold isostatic pressing b Using y mechanical pressing P M High-Speed Tool Steels 67 Cutter. 25 mm I in. ilium end mills mnVtooth in. Uxjth Radial depth of cut. . mm 0 250 in. Axial depth of cut. 25 4 mm in. Cutting oil 1 20 Tool life end point. mm wear ÍỈ 1 c End mill text on ĨÍ-6AI-4V. Hardness 321 rig. I 5 HB produced poor surface finishes. With an ASP 30 tool 20 Ọ00 parts were produced. Large broaching tools such as those shown in Fig. 18. are also being made from P M high-speed tool steels such as P M M3 and M4 to upgrade the broach material. In general large rounds for broaches are not available in conventional high-speed tool steels in sizes above about 254 mm
