A good way to large shaft surfacing

A, an overview of a large shaft bearing block ( Ø 85×70毫米) Due to the 'inner circle' and 'nap, size is reduced, demand 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 austenitic stainless steel electrode with good crack resistance A302 / A307, small energy input, low temperature preheating, annular welding stop welding, to avoid the crack and reduce the welding deformation. This method than the conventional roller frame horizontal transverse welding heat on average, small deformation, not easy craze, etc. Second, welding preparation 1, to screen large shaft bearing parts of the oil pollution, burr clean clear, grinding. 2, will stand up big axis, in addition to the bearing block parts, other central with wet asbestos sheet, in case of splash, arc collision. Here be sure to pay attention to peace, vertical fixed reliable, around the shaft space can make the welder lunch 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 maintain good, absolutely can't produce stiff, which directly affect the machining accuracy. Three, surfacing welding operation 1, in the big shaft bearing block stop oxyacetylene flame preheating, common use neutral flame heating on average, heats up to about 150 ℃. 2, use small standard welding parameters, the & # 216; 3. 2 mm welding wire, welding current of 80 ~ 110 a. 3, the operation methods: using the straight-line legal persons, from the bottom up stop horizontal, not swing, weld stack between 3/5 ~ 2/3, welding speed slightly faster, on average, as far as possible, to ensure the smoothness of weld appearance. 4, surfacing process stops in a row, as far as possible in the welding process without welding slag, liquidation can be welded together after a layer of liquidation. 5, interpass temperature control at about 250 ℃. 6, natural cooling after welding, welding layer does not crack, slag inclusion, porosity and less meat, can stop next machining. This article as the 'king will ding' initiative, declare.