Ferritic weldment of grain-refined ferritic steels for cryogenic use

Conference · Sat Aug 01 04:00:00 EDT 1981

OSTI ID:5637100

Kim, H J; Syn, C K; Morris, Jr, J W

The problem of welding grain-refined Fe-12Ni-0.25Ti for 4K service was first approached in this laboratory by using high nickel filler metals such as are often specified for ferritic steel weldments at 77K. This approach led to an undesirable brittleness in the fusion zone and a low yield strength in the weld metal. A more promising approach was developed in joint research between the Japanese steel companies, who showed that quench-and-tempered 9Ni steel may be welded for 77K service with a matching ferritic filler if a multipass GTAW technique is employed. The present paper reports the initial resultsof similar studies on ferritic GTA weldments in grain-refined 9Ni steel. Information is included on the preparation of the 9Ni steel and the weld filler metal, on the welding procedure, the microstructure of both the weld metal and the heat affected zone, and on impact toughness and fracture toughness testing at 77/sup 0/K and 4.2/sup 0/K. The results show that it is possible to weld grain-refined 9Ni steel with ferritic weld filler metal so as to retain good toughness at cryogenic temperatures. The results of this work may permit the utilization of retreated commercial grade 9Ni steel in structural applications within helium-cooled cryogenic devices where high strength and good toughness are required. (LCL)

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5637100
• Report Number(s): LBL-13017; CONF-810835-37; ON: DE82003332
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101 -- Metals & Alloys-- Preparation & Fabrication
42 ENGINEERING
420201* -- Engineering-- Cryogenic Equipment & Devices
420500 -- Engineering-- Materials Testing
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALLOYS
CRYOGENICS
CRYSTAL STRUCTURE
ELEMENTS
FABRICATION
FLUIDS
GASES
HELIUM
IRON ALLOYS
IRON BASE ALLOYS
JOINING
JOINTS
MATERIALS TESTING
MICROSTRUCTURE
NICKEL ALLOYS
NICKEL STEELS
NONMETALS
RARE GASES
STEELS
SUPERCONDUCTING DEVICES
TESTING
ULTRALOW TEMPERATURE
WELDED JOINTS
WELDING