Development Of Efficient Slag-free Self-shielded Flux-cored Wire

Arc welding wear-resistant composite sheet and workpiece technology has been widely used in mining, cement and electricity fields. There are some problems, such as low surfacing efficiency; complex welding process; labor-intensive; high cost; low properties of surfacing layer existing in large area hardfacing. Engineering practice is urgent to design and manufacture good wear resistance, simple construction process and high efficient surfacing welding material. Therefore, the development of a new type of slag-free self-shielded flux-cored wire has important application value.To solve these problems, base on the widely read literature at home and abroad in the field as well as the basis on actual research. Use low-carbon steel, design to add the right amount of ferrochrome, graphite, titanium-iron, vanadium iron, phosphorus and iron alloy powder additions in the core, draw welding flux-cored wire. After that, research the influence of three elements Ti, V, P to flux-cored wire welding layer microstructure and properties under air arc welding conditions without protection. The results are as follows:Three elements all can make the hardness of flux-cored welding layer increase, the highest microhardness reachs 621.4 HV; Ferrotitanium and ferrovanadium powder cladding generated a great deal of hard particles of TiC and VC. Provide heterogeneous nucleation particles for the matrix, refined grains, played a role in grain refinement, some V solid solution to the matrix, improve the toughness of the matrix. In ferrophosphorus powder cladding, The only possibility is that P and Fe combine to generate compound, in the cast they are easily combined to form phosphorus eutectic. The experimental results show that both have not combined to form compounds, so P exists in the surfacing in the form of a solid solution.On the basis of this study, design a new type of slag-free self-shielded flux-cored wire. The wire welding under arc welding process in the air can get welding layer, which owns beautiful molding and contains a very small amount of slag. Average macrohardness of the surfacing reachs 61.1HRC. There is no need to clean the slag during the multi-layer welding, surfacing greatly improved efficiency. The designed slag-free self-shielded flux-cored wire has been applied in an enterprise to protect the production of large area wear-resistant composite panel, and obtained good results.