Spot and seam welding are used by the electronic tube and lamp industry for welding thin gage molybdenum sheet, small gage wire, and small machined parts.

The joints are not expected to carry structural loads, and weld ductility is not an essential factor in their performance. Weld pressures and power requirements are higher for molybdenum than for other metals and alloys. The joint strength is low with essentially no ductility, due to recrystallization of the metal and the absorption of oxygen.

Ether AC or DC welding equipment can be used for the resistance welding of molybdenum. A condenser discharge type of welder or an ignitron type with 1/2-cycle timer is satisfactory. Welding conditions should be controlled to minimize contamination by air. Some shops have provided such conditions by welding under chlorinated solvents; other operators simply adjust time and current to limit the time that the hot metal is exposed to air.

Sticking and deformation of electrodes may be a problem because of the high temperatures required and the high thermal conductivity of molybdenum. Cooling or actual refrigeration of the electrodes may mitigate the difficulties.

If molybdenum sheets are to be spot welded together, it may be advisable to “etch” them prior to the welding operation. One procedure that has been used successfully requires a ten-scend immersion in a solution. After exposure to this solution the molybdenum sheet should be immersed in a hot chromic acid, glass-cleaning solution until the blue oxide disappears, then rinsed with flowing water and dried.

Zhengzhou Sanhui Co., Ltd has been dealing in tungsten, molybdenum and other refractory metals for over 24 years. We are one Alibaba 10 years’ golden supplier. We are looking forward to cooperating with you.