The choice of electrode structure to be welded to ensure safe and feasible use of the premise, according to the chemical composition of the welded materials, mechanical properties, thickness and joint type, welding structural characteristics, stress state, with conditions on the weld structure, performance requirements , welding technology, economic conditions and the construction of comprehensive test, the targeted selection of electrodes, if necessary, need for welding test.

(1) the same points used steel Welding Electrode 

â‘  consider the weld metal mechanical properties and chemical composition for ordinary structural steel, usually require the base material such as metal and weld strength, weld metal tensile strength should be used is equal to or slightly higher than the base metal electrode. For alloy steel, sometimes also called the base metal alloy composition and the same or close. In welded structures rigid, high stress joints, weld cracks easily under adverse conditions, consider choosing a low intensity than the base metal electrode. When the base material of carbon, sulfur, phosphorus and other elements at high levels, prone to weld cracking, good crack resistance should be used in basic low-hydrogen electrodes.

â‘¡ consider the performance of welded components and working conditions with the loads and impact loads on the weldment, in addition to meet the strength requirements, should primarily ensure that the weld metal has a high impact toughness and plasticity, the choice of plastic, the toughness index high low hydrogen electrode. Contact with corrosive media weldment should be based on the nature of media use and corrosion characteristics of stainless steel or other corrosion-resistant type electrode welding. In the heat, cold, wear or other special work under conditions of welded parts, should use the appropriate heat-resistant steel, cold steel, welding, or other special purpose welding rod.

â‘¢ consider the structural characteristics of welding and stress conditions on the structure of complex shape, rigidity of the Heavy welded, the welding process produces a large internal stress, easy to weld cracks, good crack resistance should be used in low-alkaline hydrogen electrode. Of discontinuity large, difficult to clean up the welding parts welding parts, should be used for rust, oxide, oil is not sensitive to the acidity of electrodes. Conditions imposed can not turn on the weldment should be used for all position welding electrode.

â‘£ consider the construction and economic conditions to meet product performance requirements in the case, should be used in electrode technology and good acidity. In small or poorly ventilated situations, should be used in acidic or low dust welding electrode. The structure of the large amount of welding work, conditions should maximize the use of high efficiency electrodes, such as iron electrodes, welding and other high-efficiency gravity, or use welding vertical down welding of the underlying class-specific electrode, in order to improve welding productivity.

(2) dissimilar steel welding electrode selection points

â‘  different intensity level + low carbon steel alloy (or low-alloy steel + low-alloy high strength steel) generally require the strength of the weld metal or joints welded metal of not less than two kinds of minimum strength, use of metal electrodes deposited strength should be able to ensure the strength of the weld and joint strength of the lower voltage of not less than the strength of base metal, and weld metal ductility and toughness should be higher but not lower than the strength of the plastic base material of poor voltage performance. Therefore, according to the two lower levels of intensity among the selected steel electrode. However, in order to prevent weld cracks, should be a higher intensity level, poor welding of steel to determine the welding process, including welding specifications, preheating temperature and post weld heat treatment and so on.

â‘¡ + austenitic stainless steel low-alloy steel weld metal should be in accordance with the chemical composition of limited value in the selection of electrodes, generally used in higher levels of chromium and nickel, plastic and cracking of the better type austenitic steels Cr25-Ni13 electrodes, in order to avoid brittle hardened tissue caused by cracks. However, poor welding of stainless steel should be determined and the welding process specification.

â‘¢ stainless steel sheet should consider the grassroots level, stratified, transition requirements of the welding electrode selection of three different properties. Of the primary (carbon steel or low alloy steel) welding, choose the appropriate intensity level of the Carbon Steel Welding Rod; stratified direct contact with corrosive media, should use the corresponding components of austenitic stainless steel electrode. The key is the transition layer (ie, cross-stratified with the primary interface) welding, must take into account the dilution of the matrix material should be used in high chromium and nickel content, good ductility and crack resistance of austenitic steels Cr25-Ni13-type electrode.