Accession Number : AD0803682

Title :   DEVELOPMENT OF WELDING PROCEDURES AND FILLER MATERIALS FOR JOINING HIGH STRENGTH LOW ALLOY STEELS.

Descriptive Note : Technical documentary rept. Jul 65-Aug 66,

Corporate Author : TRW INC CLEVELAND OH

Personal Author(s) : Peck, J. V. ; Gerken, J. M.

Report Date : OCT 1966

Pagination or Media Count : 181

Abstract : The purpose of this program was to develop welding procedures for joining martensitic and bainitic steels in the 180 to 200 ksi yield strength range. The martensitic steel, HP 9-4-25, was automatic TIG welded in thickness of 1/2, 1/4 and 0.090-inch using a commercial filler wire and no preheat or post heat treatments. Yield strengths in excess of 180 ksi were achieved with fracture toughness comparable to unwelded plate for each thickness provided that low energy inputs were used to deposit the weld metal. The 1/4-inch plate when welded over an open fixture (unsupported root) required added cooling to prevent excessive HAZ tempering. This was accomplished by using water cooled copper chill bars located adjacent to the top of the weld joint. Pressure vessels fabricated by welding heat treated HP 9-4-25 1/4-inch wall shells and elliptical ends were burst tested in the as-welded condition. The vessels failed in the seam weld heat affected zone in a ductile manner with a joint efficiency of 90.5 and 92%. The efficiencies were based on the ultimate tensile strength of the parent metal corrected by 15% for a 2 to 1 biaxial stress condition. D6AC in 1/2-inch plate form when austempered to lower bainite at 575 F for 3 to 8 hours possessed adequate strength and ductility but low fracture toughness. TIG welds made in this material exhibited marginal to low yield strength in the heat affected zones.

Descriptors :   *STEEL), (*WELDING, ARC WELDING, FRACTURE(MECHANICS), MARTENSITE, BAINITE, INERT GAS WELDING, ELECTRON BEAM WELDING, TENSILE PROPERTIES, IMPACT TESTS, NOTCH TOUGHNESS, MICROSTRUCTURE, TOUGHNESS, WIRE, METAL PLATES, ALUMINUM, TITANIUM, PERFORMANCE(ENGINEERING), HARDNESS, THICKNESS, HEAT TREATMENT, DUCTILITY, STRESSES, QUENCHING.

Subject Categories : Fabrication Metallurgy

Distribution Statement : APPROVED FOR PUBLIC RELEASE