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Title: JOINING OF MOLYBDENUM. Period covered February 15, 1956 to April 14, 1957

Abstract

An examination of available metallurgical data on molybdenum base alloys indicated that additions of Al, Ti, C, and Zr should provide good wielding properties. A group of the alloys selected was welded in a chamber containing an atmosphere of Ar. Mechanical and metallurgical tests showed that Al additions in the range of 1.18 to 0.22% gave welds that would be deflected 120 deg at room temperature. However, all the alloys containing Al showed fine porosity. Titanium additions of 0.5% produce welds which can be deflected 120 deg at temperatures between 8O and 12O deg F depending upon the amount of carbon in the alloy. Welds in 0.5% Ti with 0.O5% C produced the best results. No porosity was observed in Ti alloys. Carbon in Mo--C alloys was shown to improve the weld metal ductility by reducing the oxygen content of the base material and by a protective deoxidation action during welding. Molybdenum with 0.06% C showed the best bend ductility within the carbon range examined. The effect of welding speed on the grain size of the weld metal was examined. While it is theoretically possible to reduce the weld metal grain size by increasing the welding speed, experimental difficulties weremore » encountered due to retraction of the weld metal at speeds of 2 cm/sec. Chilling the weld failed to overcome these difficulties. Post-welding residual stresses were measured and it was found that these stresses could be eliminated by a vacuum heat treatment at 1832 deg F. The residual stresses found in the welds prior to heat treatment are sufficiently large to produce fracture without additional applied stress. The post-welding stress relief was accomplished before the weld had cooled to the transition range. Crater cracking was effectively prevented by this heat treatment. (auth)« less

Authors:
Publication Date:
Research Org.:
Westinghouse Electric Corp. Research Labs., East Pittsburgh, Penna.
OSTI Identifier:
4345543
Report Number(s):
WADC-TR-57-309
NSA Number:
NSA-12-003688
DOE Contract Number:
AF33(616)-3524
Resource Type:
Technical Report
Resource Relation:
Other Information: Project title: CFPS MATERIALS. Task title: JOINING MOLYBDENUM. Orig. Receipt Date: 31-DEC-58
Country of Publication:
United States
Language:
English
Subject:
MINERALOGY, METALLURGY, AND CERAMICS; ALUMINUM ALLOYS; ARGON; CARBIDES; COOLING; CRACKS; DUCTILITY; EXPANSION; FAILURES; GRAIN SIZE; HEAT TREATMENTS; HIGH TEMPERATURE; JOINTS; MATERIALS TESTING; MEASURED VALUES; MOLYBDENUM; OXIDATION; OXYGEN; POROSITY; QUANTITY RATIO; STRESSES; TEMPERATURE; TITANIUM ALLOYS; VACUUM; WELDING; WELDS; ZIRCONIUM ALLOYS

Citation Formats

Platte, W.N. JOINING OF MOLYBDENUM. Period covered February 15, 1956 to April 14, 1957. United States: N. p., 1958. Web.
Platte, W.N. JOINING OF MOLYBDENUM. Period covered February 15, 1956 to April 14, 1957. United States.
Platte, W.N. Fri . "JOINING OF MOLYBDENUM. Period covered February 15, 1956 to April 14, 1957". United States. doi:.
@article{osti_4345543,
title = {JOINING OF MOLYBDENUM. Period covered February 15, 1956 to April 14, 1957},
author = {Platte, W.N.},
abstractNote = {An examination of available metallurgical data on molybdenum base alloys indicated that additions of Al, Ti, C, and Zr should provide good wielding properties. A group of the alloys selected was welded in a chamber containing an atmosphere of Ar. Mechanical and metallurgical tests showed that Al additions in the range of 1.18 to 0.22% gave welds that would be deflected 120 deg at room temperature. However, all the alloys containing Al showed fine porosity. Titanium additions of 0.5% produce welds which can be deflected 120 deg at temperatures between 8O and 12O deg F depending upon the amount of carbon in the alloy. Welds in 0.5% Ti with 0.O5% C produced the best results. No porosity was observed in Ti alloys. Carbon in Mo--C alloys was shown to improve the weld metal ductility by reducing the oxygen content of the base material and by a protective deoxidation action during welding. Molybdenum with 0.06% C showed the best bend ductility within the carbon range examined. The effect of welding speed on the grain size of the weld metal was examined. While it is theoretically possible to reduce the weld metal grain size by increasing the welding speed, experimental difficulties were encountered due to retraction of the weld metal at speeds of 2 cm/sec. Chilling the weld failed to overcome these difficulties. Post-welding residual stresses were measured and it was found that these stresses could be eliminated by a vacuum heat treatment at 1832 deg F. The residual stresses found in the welds prior to heat treatment are sufficiently large to produce fracture without additional applied stress. The post-welding stress relief was accomplished before the weld had cooled to the transition range. Crater cracking was effectively prevented by this heat treatment. (auth)},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Oct 31 00:00:00 EST 1958},
month = {Fri Oct 31 00:00:00 EST 1958}
}

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