Simulation of weld cracking in heat affected zone of aluminum bronze alloy C95800

摘要

The weldability of high strength Cu-Al alloys, aluminum bronzes, could be affected by the presence of impurity elements. At present, there is no consensus on the maximum allowable limits for these elements in aluminum bronze castings. These impurities could also adversely affect the ductility and promote cracking during heat treatment. Selected impurity elements were added to aluminum bronze alloy C95800 and the weldability was assessed using a Gleeble weld simulator. The heat affected zone (HAZ) was simulated in the Gleeble and the cracking tendency was examined. The process variables for such simulation were determined. Of all the impurity elements tested, lead and bismuth were found to promote cracking in the HAZ. The other impurity elements (Zn, Sn, Se, Cr, Si and Be) did not have any significant effect on HAZ cracking. Based on the results for various combinations of the impurity elements and microstructural observations, the limits to prevent HAZ cracking in C95800 can be specified as follows: lead, 0.05%; zinc, 1.2%; tin, 0.3%; bismuth, 0.03%; selenium, 0.035%; silicon, 0.25%; chromium, 0.1%; and beryllium, 0.1%.