CHEMETAL USA specializes in the design and machining of precision tungsten and molybdenum parts for specialty applications across a wide range of industries. The processes involved are inherently difficult, due to the tungsten metals’ hardness, DBTT, and lack of room temperature ductility. The work requires knowledge and skills acquired by many specialists over decades and near-obsessive attention to detail and quality control.
To reduce strength and increase ductility, workpieces sometimes need to be heated above their brittle-to-ductile transition temperature during machining operations. The desirable machining temperature for sintered tungsten is 340~370°C when the metal loses its brittleness and becomes malleable. The machining speed must be high enough to continuously generate a chip with a dark red color. Moreover, the sintered tungsten requires a comparatively lower feed rate and cut depth because of extremely high radial forces. The optimal cutter is a grade C-2 or C-3 carbide insert. Another challenge in the machining of tungsten and molybdenum materials is surface contamination, such as the rough, stiff oxidant layer, which quickly wears and breaks down the cutting tool.
Precision Machining Service
- EDM Machining
CHEMETAL USA’s expert technicians have honed the skills necessary to overcome all the challenges involved in the precision machining of tungsten, molybdenum, and their multi-fractional metal alloys, including, copper tungsten alloy, TZM alloy, and molybdenum copper alloy, lanthanated molybdenum alloy, and lanthanated tungsten alloy.
Other Available Processes We Can Provide
Ductile-to-brittle transition temperature (DBTT) and recrystallization temperature are two important factors in the forming process of tungsten and molybdenum materials. Tungsten becomes progressively brittle as the DBTT drops and more ductile as the recrystallization temperature rises. The DBTT of tungsten materials is 200–500°C. The recrystallization temperature is 856–1200 °C. Pressing, bending, punching, forging, spinning, and cutting must occur within these two critical temperature ranges.
The grinding (machining) process for tungsten, like the forming process, is temperature-critical—the best working range of temperatures is between 343-371°C. However, copper and silver doped tungsten alloy and tungsten heavy alloy can be machined at room temperature.
Density is also critical; tungsten materials with a relative density of 93% are the hardest to machine. SiC or AL2O3 low-speed grinding is typically used to machine tungsten of this density. Tungsten materials with a relative density lower than 93% are comparatively easier to grind and cut by using wheels with high hardness (K or L), or with ruby wheels.
Joining is an integrated process including one or diverse methods, including riveting; induction welding; resistance welding; soldering and chemical vapor deposition.
CHEMETAL USA is trusted by customers worldwide for its ability to form, grind, and join specialty metals and their alloys to the highest standards and the most demanding customer specifications.
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