TLP bonding of HSLA steel

High strength low alloyed (HSLA) steels are steels used as coiled tubing materials. Fusion butt welding is commonly used during the repair procedure for coiled tubing, however, the formation of a heat affected zone (HAZ) at the weld reduces the service life of the tubes. Therefore, alternative joining techniques must be explored which minimize the HAZ and also do not change the microstructure of the steel.;In this thesis, the potential of transient liquid phase (TLP) bonding to join the QT-1000 steel was studied. The effect of TLP bonding on joint microstructure was investigated and the quality of the joint region was determined using metallurgical techniques and mechanical tests.;The research showed that good bonds were achieved using both Ag-Cu and Ni-P interlayers. Although intermetallics were not formed in the case of joints made using Ag-Cu foils, the joint strength was lower than joints made using the Ni-P interlayer.