â‘  consider the weld metal mechanical properties and chemical composition
For normal structural steel, weld metal and often require the base material of equal strength, tensile strength of weld metal 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
To withstand load and impact load 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 higher low hydrogen type 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 Rods.
â‘¢ consider the structural characteristics of welding and stress conditions
Complex shape of the structure, rigidity of the Heavy welded, the welding process produces a large internal stress, easy to weld cracks, good crack resistance should be used in basic low hydrogen electrodes. 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‘£ construction conditions and economic considerations
Product to meet the performance requirements of 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.