Joining of high-nitrogen stainless steel by capacitor discharge welding
- Bureau of Mines, Albany, OR (United States)
The effectiveness of nitrogen as an interstitial strengthening agent has led to the development of a new class of austenitic stainless steels -- high-nitrogen alloys defined by their nitrogen contents. Unlike most alloying elements, nitrogen has a very limited solubility in liquid iron-based alloys at atmospheric pressure. Therefore, high-nitrogen stainless steels presents unique challenges since the nonequilibrium nature of the material results in loss of nitrogen from the fusion and partially melted zones during welding procedures typically utilized for stainless steels, such as gas tungsten arc welding (GTAW). Loss of nitrogen from the molten base metal can result in severe weld porosity and reduced solid-solution strengthening. In this study, rapid solidification joining of a high-nitrogen stainless steel by capacitor discharge welding resulted in complete retention of the nonequilibrium level of nitrogen in the material, which is responsible for the alloy`s high strength. Joining of the high-nitrogen material using optimized welding parameters produced virtually porosity-free welds with joint efficiencies greater than 95% and no heat-affected zone. Optimization of welding parameters was aided by the use of a computer-based data collection system, which allows for a systematic analysis of the effect of welding parameters on weld properties.
- OSTI ID:
- 253660
- Journal Information:
- Welding Journal, Vol. 75, Issue 6; Other Information: PBD: Jun 1996
- Country of Publication:
- United States
- Language:
- English
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