DISSIMILAR METAL WELDS OF CERTAIN SUPERALLOYS AND STAINLESS STEELS
A welding program was conducted in support of the design and construction of the model ATR high temperature gas loop. Sections of 1 1/2-inch schedule 40 pipe of superalloy and stainless steel loop metal candidates were welded by the tungsten-electrode inert-gas process. All possible metal combinations of Hastelloy X, Hastelloy C, Haynes alloy 25, and AISI 3l6 and 347 stainless steel were made except for Hastelloy X to Hastelloy C and AISI 318 and 347 welded to themselves. There were three general guide lines for welding that were particularly emphasized. First, all the metals were to be in the solution heat treated condition when welded, thereby providing the most desirable metallurgical structure. Second, the pipe was welded with the minimum restraint to avoid any unnecessary stress build up. And third, heat build up was avoided to the extent practical to minimize the heat affected zone and the accompanying thermal stresses. The welds and heat affected zones were physically sound as determined by visual examination, radiography, fluore scent penetrant te sting, and macro and microexaminations. Bend tests indicated all welds to be ductile except for those involving Hastelloy C, many of which broke during bending. Faster cooling after welding to curtatl second phase precipitation should improve Hastelloy C weld ductibility. Most welds showed full strength efficiency at room temperature as determined by tensile tests. The lowest efficiency was 88%. Joint efficiency at 1800 deg F is apparently high for welds involving Hastelloy X and Haynes alloy 25 as indicated by a limited number of stress rupture tests. Thermal cycling tests thus far indicate that the dissimilar metal welds do not have a tendency to crack in a simulated loop thermal environment. Welding conditions for the model loop that are less ideal than those of the welding study may produce problems. Thicker metal sections of AISI 347 stainless steel and Haynes alloy 25 welded under restraint may be susceptible to cracking in the heat affected zone during welding or subsequently during loop thermal cycles. (auth)
- Research Organization:
- General Electric Co. Hanford Atomic Products Operation, Richland, Wash.
- DOE Contract Number:
- AT(45-1)-1350
- NSA Number:
- NSA-17-039501
- OSTI ID:
- 4625040
- Report Number(s):
- HW-78574
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-63
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALLOYS
ATR
CHROMIUM ALLOYS
COBALT ALLOYS
ELECTRODES
GASES
HASTELLOY
HAYNES ALLOYS
HEAT TREATMENTS
HEATING
HIGH TEMPERATURE
IN PILE LOOPS
INERT GASES
MECHANICAL PROPERTIES
MICROSCOPY
MOLYBDENUM ALLOYS
NICKEL ALLOYS
RADIOGRAPHY
REACTORS
STAINLESS STEEL-316
STAINLESS STEELS
STRESSES
TENSILE PROPERTIES
THERMAL STRESSES
TUNGSTEN
TUNGSTEN ALLOYS
WELDS