The Investigation Of Transient Liquid-phase Bonding With Steel Pipes

This paper deals with process research results concerning Transient Liquid-Phase joining process. Tests have been carried out to study TLP bonding with 20.TP304H and T91 steel pipes in an argon atmosphere.The aim of this study is to find the effect of interlayer on microstructure and mechanical properties of joint. A series of bonding conditions and heat treatments are used to develop the optimum joint microstructure. The joints produced have been characterized by metallographic examination and tensile tests at room temperature.A composite interlayer based on Fe has been obtained. One approach is presented for TLP jointing in this paper. It has a short time at higher temperature than the isothermally solidified temperature. The microstructures and properties, as well as the element distribution of the joints has examined. TLP bonding parameter is determined. The experiment finds that one of the most important consideration for producing a "good" joint will be its final composition which will depend on the interlay used. It has been shown an iron interlayer based on the Fe-Ni-B-Si system is a suitable material for use as a high-temperature interlayer for Transient Liquid-Phase joining of steel pipes. TLP bonding produced steel pipe joints, free from intermetallic precipitates and beingidentical in composition to that of the parent metal, proper mechanical is formed in the bonging seam under suitable conditions. Process parameters and interlayer design are quite flexible and can be varied to match with the particular requirements of a given alloy in a particular application. The optimum process has been obtained with the result shown in the following :1. 20 steel: Bond made at 1210℃ for 4min under 6MPa ,with BNi2 interlayer ;or bond made at 1230℃ for 4min under 8MPa ,with Fe-Ni composite interlayer2. TP304H: Bond made at 1220℃ for 4min under 6MPa with BNi2 interlayer ;or bond made at 1230℃ for 4min under SMPa ,with Fe-Ni composite interlayer3. T91: Bond made at 1250℃ for 4min under 8MPa ,with Fe-Ni composite interlayer; or made at 1265℃ for 30s and 1235℃ 3min under 8MPa.