The good method of welding a large shaft - bearing knowledge

A, an overview of a large shaft bearing block ( Ø 85×70毫米) Due to the 'inner circle' and 'nap, size decreases, and need to machining after welding. Due to the large shaft material is 42 crmo, carbon equivalent of about 0. 8%, poor weldability, prone to crack. To choose the austenitic stainless steel electrode with good crack resistance A302 / A307, small energy input, low temperature preheating, annular surfacing welding, and reduce the welding deformation in order to prevent the crack. This method than the conventional horizontal roller frame transverse heated evenly surfacing, small deformation, not easy craze, etc. Second, welding preparation 1, will be big shaft bearing block of oil, deburring, polishing and clean. 2, will stand up big axis, in addition to the bearing block parts, the rest with wet asbestos sheet, in case of splash, arc collision. Here be sure to pay attention to safety, vertical fixed more secure, around the shaft space can make welders and convenient operation, to prevent fall injury. 3, choose welding machine: ZX400 type, adopting dc reverse connection. 4, choose welding materials: A302 or A307, size & # 216; 3. 2 mm, after 250 ℃ for 1 h, into the insulation cylinder, along with it. 5, the axial center hole of the head must protect, absolutely cannot produce line, which directly affect the machining accuracy. Three, surfacing welding operation 1, in the big shaft bearing block of oxyacetylene flame preheating, generally adopts uniform neutral flame heating, rising up to about 150 ℃. 2, the welding parameters using small specification, & # 216; 3. 2 mm welding wire, welding current of 80 ~ 110 a. 3, the operation methods: using the straight-line legal persons, horizontal from the bottom up, not swing, bead overlap between 3/5 ~ 2/3, welding speed slightly faster even as far as possible, to ensure the weld surface roughness. 4, try to continuous surfacing process, don't need to clean up the welding slag in the process of welding, weldable after a layer of clean up together. 5, interpass temperature control at about 250 ℃. 6, natural cooling after welding, welding layer does not crack, slag inclusion, porosity and less meat, just can carry out under one machining. In this paper, as the 'king will ding' original, declare.