Quantitative research on the heat affected zone of weave bead welding for Invar alloy

Quantitative research on the heat affected zone （HAZ） of weave bead welding （WBW） joint for Invar alloy is carried out in this paper. Based on the morphology and related data analysis of the weld seam,the width difference of each layer and the forming mechanism are analyzed. Results show that the bottom layer （Layer 1） has the widest HAZ and the smallest fluctuation,which reaches 1 200 μm. HAZ width of layer 2 to 5 is relatively narrower which is basically below 600μm,while the amplitude fluctuation is greater. The main reason lies in the welding path. The long straight welding without weave causes the base metal near the groove fully melts which causes by the long straight welding without weave,while welding with weave leads to the uneven and inadequate melting of metal near groove.