Effects of welding on weldment mechanical performance in two austenitic steels
The effect of autogenous gas-tungsten arc-welding on the mechanical performance of two austenitic steels has been evaluated for cable jackets of force-cooled superconductor coils. The original candidate material was Nitronic 40, a nitrogen-strengthened stainless steel. The in-situ reaction heat treatment at 700/sup 0/C necessary for the formation of the superconducting A15 phase results in severe degradation of the cryogenic tensile ductility in the weld metal. The search for an alternate material led to JBK-75, a modified A-286 type ..gamma..' precipitation hardening iron-based superalloy. Observations of a tensile strength mismatch between base metal and the weaker weld metal in JBK-75 prompted a study into the aging response in weldments of this alloy. Localized strain through slip step traces show an easy path of deformation within the solidification structure. Weldment strength varies with grain size. It was found that through post-weld annealing treatments at 950/sup 0/C, prior to aging, weldment hardness levels can be matched. However, although increased strength levels are obtained in the weld metal, concomitant decreases in base metal strengths are suffered, presumably due to observed grain growth. 24 figures, 9 tables.
- Research Organization:
- Lawrence Berkeley Lab., CA (USA)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 6753014
- Report Number(s):
- LBL-14750; ON: DE83001400
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360103* -- Metals & Alloys-- Mechanical Properties
420201 -- Engineering-- Cryogenic Equipment & Devices
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AGING
ALLOY-A-286
ALLOYS
ALUMINIUM ADDITIONS
ALUMINIUM ALLOYS
ANNEALING
ARC WELDING
AUGER ELECTRON SPECTROSCOPY
CHROMIUM ALLOYS
CORROSION RESISTANT ALLOYS
CRYSTAL STRUCTURE
DATA
DEFORMATION
ELECTRIC COILS
ELECTRIC CONDUCTIVITY
ELECTRICAL EQUIPMENT
ELECTRICAL PROPERTIES
ELECTROMAGNETS
ELECTRON MICROSCOPY
ELECTRON SPECTROSCOPY
EQUIPMENT
EXPERIMENTAL DATA
FABRICATION
GAS TUNGSTEN-ARC WELDING
GRAIN GROWTH
HARDNESS
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
HEAT TREATMENTS
INFORMATION
IRON ALLOYS
IRON BASE ALLOYS
JOINING
JOINTS
MAGNET COILS
MAGNETS
MANGANESE ALLOYS
MATERIALS
MECHANICAL PROPERTIES
METALLOGRAPHY
MICROHARDNESS
MICROSCOPY
MICROSTRUCTURE
MOLYBDENUM ALLOYS
NICKEL ALLOYS
NUMERICAL DATA
PHYSICAL PROPERTIES
SCANNING ELECTRON MICROSCOPY
SEGREGATION
SPECTROSCOPY
STAINLESS STEEL-21-6-9
STAINLESS STEELS
STEELS
SUPERCONDUCTING DEVICES
SUPERCONDUCTING MAGNETS
TENSILE PROPERTIES
TITANIUM ALLOYS
WELDED JOINTS
WELDING