When steel pipe manufacturers produce welded steel pipe, they usually use flux in the welding process, flux has great effects on porosity and slog, which also has great effects on the quality of welded steel pipe. Next, Prime Steel Pipe will share that for you.
Alkalinity is one of the main performance indicators of flux, which has a great influence on the toughness of welds. The current pipeline welding is generally used alkaline flux, especially fluorine alkaline flux.
In the use of the following problems: With the increase in flux alkalinity and welding speed, weld pores, slag defects significantly increased, limiting the welding yield increased. Analysis of reason: over-alkaline flux of CaO, CaF, MgO and other small molecules, more difficult to form a polymer, difficult to discharge from the pool, easy to produce slag, stomatal segregation, and even crack.
Pipeline steel submerged arc welding flux should be controlled in the B Ⅱ W = 1.6 below, in order to achieve toughness and pores, the best combination of slag. In addition, foreign pipe production using neutral, acidic flux, worth learning from.
2.The mechanical inclusions in the flux
Mechanical inclusions are mainly iron, oil, rust and so on. Easy to cause slag, pores, segregation and other defects. Production, in the pipe production process, should minimize this type of mechanical inclusions, which will be the minimum welding defects.
3.The flux of H2O, S, P content
1) H2O easily decomposed into gas, damage the stability of the arc, before welding, the flux must be dried to remove the surface adsorption of H2O;
2) S reacts with the oxygen in the molten pool to form SO2, destroys the stability of the bath, produces pores, slag and other defects. In addition, the S content is too large to seriously affect the impact toughness of the weld. Under normal circumstances, the flux of w (S) <0.06%;
3) P reacts with the oxygen in the molten pool to form P2O5, destroys the stability of the bath, produces pores, slag and other defects. In addition, the P content is too large to seriously affect the impact toughness of the weld. Under normal circumstances, the flux w (S) <0.08%.