Dissimilar steel welding Welding Electrodes choice points (1) carbon steel with different intensity level + low alloy steel (or low alloy + low alloy high strength steel) General requirements for the strength of the weld metal or joints of not less than the minimum two weld metal strength, the strength of the deposited metal electrodes chosen should be able to ensure the strength of the welds and joints are not less than the strength of the lower strength of the base metal guillotine, plasticity and impact toughness of the weld metal shall not be less than the higher strength and less plastic guillotine the performance of the base material. Therefore, can be chosen on a lower intensity level two steel welding rod. However, in order to prevent welding crack, the intensity level should be higher, poor weldability of the steel species to determine welding process, including the welding specifications, preheating temperature and post-weld heat treatment. ② low alloy steel + austenitic stainless steel Should be in accordance with the values ??of the chemical composition of the deposited metal is limited to selection of the welding rod, generally used in high chromium and nickel content, good ductility and crack resistance Cr25-Ni13 type austenitic steel electrode, to avoid brittle hardened tissue resulting cracks. But should be poor welding stainless steel to determine welding process and specification. (3) stainless clad steel Should consider the selection of three different performance of the Copper Electrodes on the grass-roots level, multi-layer, the transition layer welding requirements. Welding of primary (carbon or low alloy steel), the choice of the appropriate strength grade structural steel electrode; stratified direct contact with corrosive media should be used in the corresponding component of austenitic stainless steel electrode. The key is the welding of the buffer layer (i.e., a cladding layer with grassroots interface), must be taken into account the dilution effect of the matrix material should be chosen high chromium and nickel content, good ductility and crack resistance Cr25-Ni13-type austenitic steel electrodes
(1) low-hydrogen electrodes at room temperature more than 4h, should be re-drying. Repeat drying Views should not be more than three times.
(2) drying Welding Wire, it is prohibited to put the welding rod suddenly high temperature furnace, or removed from the high-temperature furnace suddenly cooled, to prevent electrode due to cold and hot temperatures drug leather cracking phenomenon.
(3) the electrode drying should should be on the record record grades, batch number, temperature, time, and content.
(4) during the electrode drying, technical personnel should be responsible, responsible for the operation, inspection and checking, not less than once each batch of electrodes, and the signature on the operating record.
(5) drying electrodes, the electrodes should not be into a crib or a bundle stacked, should be laying into layered stacked each layer electrode can not be too thick (generally 1 to 3 layers) to avoid electrode drying unevenly heated and moisture is not easy to rule out.
(6) The open-air operation, the electrodes must be safekeeping, does not allow the open storage of low-temperature oven thermostat to save, or even the next day before use to re-drying. Requirements of electrode baking: the electrode baking requirements Manual manual are subject to the following requirements. Electrode Repeat baking no more than twice, the acid coated electrode baking temperature to 120 of 150 ° C, holding time 1h, low alkaline hydrogen type welding electrode baking temperature of 350 ° C, holding time 1h