Mechanism of Improvement of the Bend Ductility of the Overlay Weld prepared with Zirconium Containing Low Chromium type Steel Filler Metal

Study on Welding of the Low Interstitial Ferritic Stainless Clad Steel (Report 4)

Abstract

The mechanism of improvement of the bend ductility of the low interstitial ferritic stainless steel overlay welds prepared with zirconium containing low chromium type steel filler metal for the first layer has been investigated.
In the previous report, it was indicated that the thickness of chromium carbide, 475°C embrittlement and grain coarsening were factors affecting embrittlement in the overlay welds.
Decreasing in chromium content in the first layer of the weld metal contributed to mitigation of 475°C embrittlement and decreasing of the thickness of chromium carbide on the grain boundary in the overlay weld metal. Addition of zirconium to the first layer of the ferritic stainless steel overlay welds made the thickness of chromium carbide decrease and also the grain size refine.
These resulted in an excellent weld ductility for the overlay welds.