Study 1--The effect of temper cycle, mechanical treatments, weld geometry and welding conditions on sheet steel spot weld fatigue resistance

Journal Article · Sun Aug 01 04:00:00 EDT 1993 · Welding Research Council Bulletin; (United States)

OSTI ID:5940095

Lawrence, F V; Corten, H T ^[1]; McMahon, J C ^[2]

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1. Univ. of Illinois, Urbana, IL (United States)
2. Advanced Cardiovascular Systems, Temecula, CA (United States)

This study summarizes the initial two-year project sponsored by the American Iron and Steel Institute in which way of improving the fatigue resistance of electrical resistance spot welds were sought. Both low-carbon and HSLA steels were considered. Testing was limited to the tensile-shear weld geometry. Both galvanized and bare sheet steel were used. Improvement techniques considered were: control of residual stresses, control of weld geometry, increasing base metal strength, and state of the steel sheet surface. The most important result of this study was to show that the fatigue resistance of tensile-shear spot welds (particularly HSLA) could be greatly improved by treatments which either reduced the tensile residual stresses resulting from welding or induced compressive residual stresses at the critical notch-root site of crack initiation and early growth. The improvement possible through modification of weld geometry were smaller than those possible through control of residual stresses except for the improvements resulting from the reduction of joint rotation as shown by Davidson. Increasing the base metal tensile strength did not greatly alter the fatigue resistance of as-welded tensile-shear spot welds presumably because such increases are off-set by higher (tensile) residual stresses. The state of the steel sheet surface, that is, galvanized or bare, had little if any influence on the test results. A three stage model for predicting the fatigue life of tensile-shear spot welds was developed.

• OSTI ID: 5940095
• Journal Information: Welding Research Council Bulletin; (United States), Journal Name: Welding Research Council Bulletin; (United States) Vol. 384; ISSN 0421-2118; ISSN WRCBB3
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101 -- Metals & Alloys-- Preparation & Fabrication
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
CRACK PROPAGATION
FABRICATION
FATIGUE
HEAT TREATMENTS
IRON ALLOYS
IRON BASE ALLOYS
JOINING
JOINTS
MATHEMATICAL MODELS
MECHANICAL PROPERTIES
RESIDUAL STRESSES
SHEETS
STEELS
STRESSES
TEMPERING
TENSILE PROPERTIES
WELDED JOINTS
WELDING