The principle and basis of Welding Electrode selection
The choice of the principle of choosing electrode electrode welding structure should guarantee under the premise of safe and reliable use, according to the chemical composition of the welding material, mechanical properties, thickness and joint type of the stress of welding structure characteristics, welding performance of structure under the conditions of use requirement, tianjin golden bridge Welding Electrodes plant construction conditions and comprehensive test technology and the economic benefits, such as targeted use of electrodes, if necessary, the welding test.
(A) the same steel Welding Electrode selection point
1) the chemical composition of weld metal mechanical properties of ordinary steel, usually require the weld metal and base material, such as strength, tensile strength should be equal to or slightly higher than that of base metal electrode deposited metal. For alloy structural steel, alloy compositions may also require the same or close to the substrate material. In the case of rigid welding structure, high stress joints, and easy to produce cracks when welding, you should consider using low strength than base metal electrode. When the content of carbon, sulfur, phosphorus and other elements of the substrate material is too high, it is easy to produce cracking and anti-cracking weld. The electrode should be used for the alkaline low hydrogen Welding Electrode.
2) consider using performance under dynamic load and impact load of weldment welded components and working conditions, in addition to meet the strength requirement, the main should guarantee the weld metal has higher impact toughness and ductility, choose plastic, high toughness index of low hydrogen type Welding Electrode. High temperature, low temperature, wear resistance, or other welding work under special conditions, suitable heat resistant steel, low temperature steel, Welding Electrode or other special purpose.
3) welding structure characteristics and stress under the condition of complicated shape structure, rigid heavy welding, the welding process to produce a lot of pressure, welding cracks easily, has good crack resistance, alkaline low hydrogen Welding Electrode should be used. The welding parts that are hard to clean in uneven strength should use rust, scale, and oil insensitive acid Welding Electrodes. The welding parts that cannot be turned over should be used for full position Welding Electrodes.
4) considering the construction and economic conditions to meet the product performance requirements, welding technology and good acidity should be adopted. Welding Electrode In small or poorly ventilated areas, solder electrodes should be used or low dust. Should use the high efficiency of electrode, such as iron powder Welding Electrodes, high efficiency welding, such as gravity or use in the structure of bottom electrode welding workload, conditions, specific to the type of vertical down Welding Electrode, in order to improve welding productivity.
(2) selection point of foreign steel Welding Electrode
Level + 1) different strength low alloy steel (or low-alloy steel + high strength low alloy steel) general requirements not less than two kinds of the minimum degree of weld metal or metal welding joint strength, deposition of the metal electrode selection intensity is able to ensure that the weld metal toughness and ductility and impact strength, the strength of the weld is not lower than base material of the strength of the underside of the joint strength, Welding Electrode at the same time should not be higher than the side of the substrate material is poor ductility performance. Therefore, steel wire selection is produced according to the low intensity level. However, in order to prevent welding cracks. Should be a higher level of strength, welding poor steel determination of welding process, including welding specification, preheating temperature and post-weld heat treatment.