304 stainless steel plate ferritic heat-resistant steel welding
The main problem of the welding of ferritic heat-resistant steel is the embrittlement of the heat-affected zone (including the decrease of the ductility caused by the grain growth in the heat-affected zone near the fusion zone, the embrittlement at 475 ℃, The tendency of cracks is higher and the toughness is lower at room temperature.
304 stainless steel plate , preheating: the base metal metal preheating, so that the welding joints in a better state of toughness to reduce the impact of welding stress, can more effectively prevent the occurrence of cracks. But the preheating temperature can not be too high, to avoid overheating, generally not more than 150 ℃. For high chromium content of ferritic heat-resistant steel, the preheating temperature should be higher, sometimes up to 200 ~ 300 ℃.
304 stainless steel plate , welding consumables: can be used with the base metal similar to the ferrite chromium steel electrode, can also use austenitic electrode.
304 stainless steel plate, the welding line energy: the use of small energy line to prevent the welding joints overheating. As far as possible to reduce the welding joints in the high temperature of the residence time, the use of large welding speed, to minimize the lateral swing of the narrow bead, do not continuous welding, until the previous weld to the preheating temperature, allowed to weld a weld The
4, post-weld heat treatment: the welding joints of the organization to improve its plasticity and toughness, generally can be used air-cooled annealing. Once the welded joints appeared brittle, short-term heating to 600 ℃ air cooling, can eliminate 475 ℃ embrittlement; heated to 930 ~ 950 ℃ quenching, can eliminate σ phase brittle.