Weldability of iron aluminides
Corrosion-resistant, weldable iron-aluminide alloys with improved high-temperature strength are being developed for structural applications, and for weld overlay cladding of conventional structural steels and alloys. The weld hot cracking of iron-aluminide alloys is highly variable to over a wide range of aluminum content. In general, the higher aluminum content alloys are somewhat more resistant to hot cracking, and by careful choice of alloying additions (and balancing of multiple additions), cracking resistance equivalent to commercial austenitic stainless steels can be achieved. Improved weldability, however, often comes at the expense of high-temperature strength. Delayed cold cracking, presumed to be hydrogen-related, is also an important consideration in welding these alloys, either as monolithic materials, or as weld overlay cladding on stainless or low alloy steel substrates. The authors are employing various combinations of preheat and postweld stress relief heat treatments to assess the severity of this problem, and have determined that heat treatment in excess of 400 C following welding will be required to avoid delayed cracking. Due to the difficulties encountered in fabricating some of the alloy compositions into wire or rod, they are also pursuing the formulation of coated electrodes for use in shielded metal-arc (SMA) welding. Initial attempts have shown very high aluminum losses in the welding arc, and additional batches of electrodes are being formulated and produced.
- Research Organization:
- Oak Ridge National Lab., TN (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 10184564
- Report Number(s):
- CONF-9305135-11; ON: DE94019114; TRN: AHC29423%%43
- Resource Relation:
- Conference: 7. annual conference on fossil energy materials,Oak Ridge, TN (United States),11-13 May 1993; Other Information: PBD: [1993]
- Country of Publication:
- United States
- Language:
- English
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