Development Of Advanced Performance Self-shielded Flux-cored Wire For Hardfacing

Self-shielded flux-cored wire is one of continue welding material which can finish automatic work in disadvantageous situation without assistant protect manner, presently widely used in foundation construction building of China. Because there is no credible merchandise have been developed by Chinese enterprise or institute, all kinds of self-shielded flux-cored wire used in china have to purchase from abroad, and it is the most costly kind of flux-cored wire in CIF, which China has imported. So most professionals of welding material research regarded it necessary to develop the self-shielded flux-cored-wire as quickly as possible. For self-shielded flux-cored wire in market still have some detects, the author wants to develop a kind of self-shielded flux-cored-wire for hardfacing to meet the national market demand, which have excellent work capability, good cost performance, standout welding ability and little harm to environment. For this reason the author decide to put forward a metal cored self-shielded flux-cored wire, in this way the author expect to ameliorate the problem of welding fume and increase the welding efficiency. During this subject research the author mainly investigate and examine the self-shielded mechanism base on mix metal powder such as C-Mn-Si or C-Al-Si, which without fluoride and produce little slag and fume during welding. In this subject the author has developed a self-shielded flux-cored wire of low alloy, which has good welding ability, the deposited alloy composition is 8Cr7Mn3Ti2Si2B and its face rigidity is HRC 62; For developing a self-shielded flux-cored wire whose welding ability much better, the author has developed a low weld fume and harmfulness self-shielded flux-cored wire, the deposited alloy composition is 9Cr6Al4Si3TiMoB and its face rigidity is HRC 48, the wear resisted performance of the two wire's deposited metal are better 23.6 and 8.6 times than that of hardfacing solid wire (25Cr3Mo2MnV)'s deposited metal. After investigate the CrSi2 which was detected in weld metal, the author discovered the Vapor-Liquid-Solid mechanism can well express the formation of CrSi2, and the being of CrSi2 in deposited metal has proved synchronously the existence of VLS mechanism in welding metallurgic process. So the author consider an in-depth research on VLS mechanism would help to express the welding metallurgic process reasonable and forecast the structure of deposited metal effectively.