Pvc coated welded wire mesh weld zone for effective protection
Pvc coated welded wire mesh characteristics of metallurgical process, why should the effective protection of the weld zone
Pvc coated welded wire mesh metallurgical process characteristics: During arc welding, a series of physical and chemical reactions are carried out between the molten metal, slag and gas, such as oxidation and reduction of metals, dissolution and precipitation of gases, and removal of impurities. Wait. Therefore, the weld pool can be regarded as a micro metallurgical furnace. However, the pvc coated welded wire mesh metallurgical process is different from the general smelting process, and has the following main features:
(1) high metallurgical temperature: easy to cause burning and evaporation of alloying elements;
(2) Short metallurgical process: During welding, due to the small volume of the weld pool (generally 2 to 3 cm3), the cooling rate is fast, the liquid residence time is short (the molten pool is formed from solidification for about 10 s), and various chemical reactions cannot reach equilibrium. State, segregation of chemical composition unevenness occurs in the weld.
(3) Poor metallurgical conditions: The weld pool is generally exposed to the air. The gas, rust and oil stains around the bath will be decomposed into atomic oxygen and nitrogen at the high temperature of the arc, which is easy to produce chemistry with metal elements. reaction. The oxides and nitrides formed by the reaction are mixed into the weld to reduce the mechanical properties of the weld; the moisture in the air is decomposed into hydrogen atoms, and defects such as pores and cracks are generated in the weld, and "hydrogen embrittlement" occurs.