Failure mode transition in AHSS resistance spot welds. Part II: Experimental investigation and model validation

2011 ◽  
Vol 528 (29-30) ◽  
pp. 8344-8352 ◽  
Author(s):  
M. Pouranvari ◽  
S.P.H. Marashi ◽  
D.S. Safanama
Keyword(s):  
Experimental Investigation ◽  
Model Validation ◽  
Failure Mode ◽  
Mode Transition ◽  
Spot Welds ◽  
Resistance Spot ◽  
Failure Mode Transition ◽  
Resistance Spot Welds

scholarly journals Effect of weld nugget size on failure mode and mechanical properties of microscale resistance spot welds on Ti–1Al–1Mn ultrathin foils

2018 ◽  
Vol 10 (7) ◽  
pp. 168781401878528 ◽  
Author(s):  
Feng Chen ◽  
Shiding Sun ◽  
Zhenwu Ma ◽  
GQ Tong ◽  
Xiang Huang
Keyword(s):  
Mechanical Properties ◽  
Failure Mode ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Weld Nugget ◽  
Interfacial Failure ◽  
Spot Welds ◽  
Resistance Spot ◽  
Resistance Spot Welds ◽  
Pullout Failure

We use tensile–shear tests to investigate the failure modes of Ti–1Al–1Mn microscale resistance spot welds and to determine how the failure mode affects the microstructure, microhardness profile, and mechanical performance. Two different failure modes were revealed: interfacial failure mode and pullout failure mode. The welds that fail by pullout failure mode have much better mechanical properties than those that fail by interfacial failure mode. The results show that weld nugget size is also a principal factor that determines the failure mode of microscale resistance spot welds. A minimum weld nugget size exists above which all specimens fail by pullout failure mode. However, the critical weld nugget sizes calculated using the existing recommendations are not consistent with the present experimental results. We propose instead a modified model based on distortion energy theory to ensure pullout failure. Calculating the critical weld nugget size using this model provides results that are consistent with the experimental data to high accuracy.

Prediction of the failure mode of automotive steels resistance spot welds

2020 ◽  
Vol 25 (6) ◽  
pp. 511-517
Author(s):  
Mohsen Sheikhi ◽  
Shaghayegh Jaderian ◽  
Yousef Mazaheri ◽  
Majid Pouranvari
Keyword(s):  
Failure Mode ◽  
Spot Welds ◽  
Resistance Spot ◽  
Resistance Spot Welds

Effect of weld nugget size on overload failure mode of resistance spot welds

2007 ◽  
Vol 12 (3) ◽  
pp. 217-225 ◽  
Author(s):  
M. Pouranvari ◽  
H. R. Asgari ◽  
S. M. Mosavizadch ◽  
P. H. Marashi ◽  
M. Goodarzi
Keyword(s):  
Failure Mode ◽  
Weld Nugget ◽  
Spot Welds ◽  
Resistance Spot ◽  
Resistance Spot Welds

A Critical Nugget Size Prediction Model for Al-Si Coated Press Hardened Steel Resistance Spot Welds

2021 ◽  
pp. 1-27
Author(s):  
Ruiming Chen ◽  
Ming Lou ◽  
YongBing Li ◽  
Blair E. Carlson
Keyword(s):  
Fracture Mode ◽  
Shear Fracture ◽  
Sheet Thickness ◽  
Hardened Steel ◽  
Mode Transition ◽  
Spot Welds ◽  
Resistance Spot ◽  
Transition Mechanism ◽  
Lap Shear ◽  
Resistance Spot Welds

Abstract For the automotive industry, it is important to predict the fracture mode of resistance spot-welded joints. Traditional 4t0.5 (where t is sheet thickness) criterion for the transition from interfacial fracture (IF) to button pullout fracture (BPF) mode is not applicable for press hardened steel, PHS, welds. This study aims to investigate the effect of Al-Si coating and critical heat affected zone (CHAZ) location on the lap-shear fracture mode transition mechanism of Al-Si coated PHS welds. It was found that in-situ tempering pulse after the welding stage could change the relative location of the CHAZ and weld nugget, which in turn, had a significant effect upon the fracture mode transition. Thus, a new analytical model was built to predict the critical nugget size for Al-Si coated PHS, wherein the Al-Si coating and the CHAZ location are considered as critical factors for predicting the fracture mode transition of PHS spot welds and are incorporated into this model. A reasonable correlation of the model to experimental data was achieved.

Influence of Paint Baking on the Energy Absorption and Failure Mode of Resistance Spot Welds in TRIP1180 Steel

2021 ◽  
Vol 143 (9) ◽  
Author(s):  
D. V. Marshall ◽  
D. Bhattacharya ◽  
J. G. Speer
Keyword(s):  
Energy Absorption ◽  
Failure Mode ◽  
Low Energy ◽  
Interfacial Failure ◽  
Spot Welds ◽  
Resistance Spot ◽  
Pull Out ◽  
Resistance Spot Welds ◽  
Tension Testing ◽  
Cross Tension

Abstract Resistance spot welds (RSWs) in advanced high strength steels frequently exhibit interfacial failure during cross-tension testing: a mode of fracture associated with low-energy absorption. Automotive assembly lines include a paint application and baking cycle after the vehicle assembly and joining processes to cure paint and any adhesives used for assembly. In this article, the effects of a typical baking cycle: 180 °C for 20 min, on the failure mode and energy absorption during cross-tension testing of RSWs made in a TRIP1180 steel are reported. Further, short-time baking cycles of 30 s, 90 s, and 4 min were employed to investigate how quickly these baking effects are activated. RSWs, which exhibited interfacial failure and a low-energy absorption of 30.9 J in the as-welded condition, saw a change in a failure mode to partial interfacial failure and a 260% increase in energy absorption after baking for 30 s. After baking for a longer time (4 min), welds failed by button pull-out and exhibited a 296% increase in energy absorption during cross-tension testing. Baking for the full 20 min resulted in no additional improvement than was observed in the 4 min condition. The mechanisms responsible for the majority of the improvement in weld performance during baking are found to be activated after only 30 s of baking.

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