TUNGSTEN EXTRUSION DEVELOPMENT PROGRAM.
Final technical documentary rept. for 2 Dec 60- 27 Jun 63,
WAH CHANG CORP ALBANY OREG
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Procedures were developed for preparation of tungsten-3 percent molybdenum extrusion billets by arc casting and by pressing and sintering. Round extrusions were made to evaluate die lubrication and die coatings in temperatures ranging from 3200F to 4000F at reduction ratios as high as 171. Efforts to obtain wrought extrusion billets by extruding large cast ingots at 2300F and 2.61 were not successful because longitudinal cracking developed in the extrusion. Efforts to meet program target dimensional and surface requirements with arc cast tungsten-3 percent molybdenum were unsuccessful. However, extruded tungsten T sections up to 138 inches long having surface finishes better than 100 RMS and dimensional run-out within .010 inch were successfully produced from pressed and sintered starting material. The extrusion conditions necessary to achieve the program target dimensions resulted in a hot-worked microstructure which has a high ductile-brittle transition temperature and relatively low strength. Because of the undesirable microstructure achieved and the lack of requirement for tungsten extrusions of the target configuration, the program was terminated at the end of the Phase III effort. Author