BÖHLER FOX 20 MVW is a core wire alloyed covered electrode with a basic coating for shielded metal arc welding. The 11Cr-1Mo-0.5W-V type deposit has a tempered martensitic structure and good mechanical properties after post weld heat treatment and after quenching and tempering. The manufacturer directs it to joints in tube, pipe, forgings and castings made of creep resistant steels of the X20CrMoW12-1 kind, used in thermal power plants.
The base materials are 1.4922 (X20CrMoV11-1), 1.4935 (X20CrMoWV12-1) and 1.4923 (X22CrMoV12-1). The composition was chosen for high creep resistance and ductility of the deposit after heat treatment, and the material is approved for long term service under creep conditions up to 650 degrees C. The basic coating keeps the level of diffusible hydrogen in the weld low.
- Classification EN ISO 3580-A: E CrMoWV12 B 4 2 H5
- Coating: basic
- Current: DC+
- Diameters: 2.5 / 3.2 / 4.0 / 5.0 mm
- Lengths: 350 and 450 mm
- Approvals: TÜV (01082.), KTA 1408.1 (8088), CE
Martensitic steel with 12 percent chromium needs preheating and an interpass temperature held in a narrow window, according to the data sheet of the base material. Do not leave the joint without heat treatment after welding, because the martensite has to be tempered, or the weld will crack. Before the joint goes into the furnace let it cool to the temperature given in the procedure, so that the transformation can finish. Dry the electrodes and carry them in a quiver for the whole shift.
