The Nitrogen Content of Fe-Cr and Fe-Ni Weld Metals

Fundamental Study on the Nitrogen Absorption by Fe-Cr-Ni Weld Metals (Report 2)

Abstract

The nitrogen contents of Fe-Cr and Fe-Ni weld metals deposited in the atmosphere of nitrogen, air or nitrogen oxygen gas mixture's were systematically determined. Some of them were compared with the solubility of nitrogen in the alloys concerned. The extent of porosity was also investigated.
The main results are summarized as follows:
1. The nitrogen contents were shown as a function of the concentration of chromium or nickel.
2. The nitrogen content of the Fe-Cr weld metals made in a nitrogen atmosphere increases continuously with the chromium content, but in an air atmosphere it exhibits a minimum at about 1 % chromium, thereafter increasing with the chromium content as well as in a nitrogen atmosphere.
3. The enhancement of nitrogen absorption by the coexistence of oxygen with nitrogen in welding atmospheres does not take place in high chromium steel welds.
4. At low contents, nickel scents to increase somewhat the nitrogen content of the Fe-Ni weld metals. And at higher contents it gradually reduces the nitrogen absorption.
5. The blowholes in the weld metals seem to be reduced by increasing the chromium content of the electrode wires.