Effects of Welding Parameters on Strength and Corrosion Behavior of Dissimilar Galvanized Q&amp;P and TRIP Spot Welds

The occurrence of liquid metal embrittlement (LME) during the resistance spot-welding of a zinc-coated Advanced High-Strength Steel (TRIP-aided AHSS) is investigated in this work. Welds are generated using controlled degradation of the welding conditions to favor the occurrence of LME cracks in a two-sheets homogeneous configuration. Detailed inspection of the welds shows that electrode misalignment, short holding time, low electrode force and long welding time constitute a propitious environment for both inner and outer LME cracks. A statistical analysis allows weighting and interpreting of the significance of the welding parameters. Electrode misalignment and reduced holding time appear as the most influential parameters in the design of experiment. Moreover, it is worth noting that standard ISO welding conditions are prone to avoid any LME cracks in the investigated two-sheets homogeneous configuration.

Section: Introductionmentioning

confidence: 99%

Effect of Severe Welding Conditions on Liquid Metal Embrittlement of a 3rd-Generation Advanced High-Strength Steel

Siar

Benlatreche

Dupuy

et al. 2020

“…Among the growing application of high strength steels [1][2][3][4], duplex stainless steels (DSSs) are gaining increasing attention from the chemical, petrol, and transportation [5][6][7] industries, thanks to their mechanical properties and corrosion resistance [8][9][10][11]. However, the industrial application of DSSs is in only~1% among all the types of stainless steels [12].…”

Section: Introductionmentioning

confidence: 99%

Physical and Theoretical Modeling of the Nitrogen Content of Duplex Stainless Steel Weld Metal: Shielding Gas Composition and Heat Input Effects

Varbai

Májlinger

2019

Duplex stainless steels (DSSs) are gaining more and more attention in corrosion-resistant applications and also in the transport and automotive industry. The outstanding mechanical and corrosion properties of DSSs highly depends on the austenite-to-ferrite phase balance (A/F). This phase ratio can shift in a large scale during welding. Thus, the heat input and the shielding gas composition should be optimized. Nitrogen addition to argon shielding is frequently used in DSS welding, because it is a potent austenite former. The dissolved nitrogen content in the heat-affected zone and the weld metal (WM) predetermines the A/F. To determine the effect of heat input and nitrogen content in shielding gas, two different heat inputs and six different gas compositions were used in autogenous tungsten inert gas welding. An improved theoretical model was established in order to simulate the WM dissolved nitrogen content, which calculates it with less error than the initial models. The correlation between nitrogen content and arc voltage was also determined. This improved model delivers the basics for shielding gas selection and the subsequent weld design for optimal A/F for industrial applications.

“…In response to enforceable vehicle fuel efficiency regulations, such as the Corporate Average Fuel Efficiency (CAFE) Standards intended to improve the fuel economy of light trucks and cars [1], automotive equipment manufacturers have developed and applied various lightweight technologies using high-strength steel (HSS) in their vehicle bodies [2][3][4]. In addition to meeting fuel efficiency standards, these lightweight vehicle body parts must also meet various vehicle crashworthiness standards, such as the Small Overlap Frontal Crashworthiness Evaluation.…”

Section: Introductionmentioning

confidence: 99%

Adaptive Resistance Spot Welding Process that Reduces the Shunting Effect for Automotive High-Strength Steels

2018

Although short-pitch resistance spot welding (RSW) significantly increases vehicle body strength, its application has been limited because of the associated shunting effect. In this study, a reference-based adaptive RSW process intended to minimize the shunting effect was proposed, and a related RSW system that controls welding current and power was developed to implement the adaptive method. The proposed RSW method compensates for the heat input loss caused by the shunting effect based on the estimated weld pitch and reference data obtained under suitable welding conditions. An exponential model was developed using a unique indicator (i.e., the ratio of the adaptive welding heat input to the reference welding heat input until the reference welding power curve peak) to estimate the weld pitch. A logistic growth model was next developed based on the relationship of the nugget diameter, heat input, and weld pitch to estimate the heat input compensation. A unique strategy using power control with a modified reference power curve was applied to supply the calculated heat input compensation. The experimental results intended to validate the proposed adaptive RSW process indicated that the proposed process effectively reduced the shunting effect and produced an improved nugget shape relative to the conventional RSW process.