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With the increasing demand for safety, energy saving and emission reduction, Advanced High Strength Steels (AHSS) have become very attractive materials for automobile makers. Welding of AHSS remains one of the technical challenges in the successful application of AHSS in automobile structures, especially when durability of the welded structures is required. In this study, 2.0 mm uncoated DP780 was investigated. GMAW welding parameters for lap joints of this steel were developed in order to obtain different weld geometries defined by weld toe angle, weld leg sizes, and weld penetration. Metallurgical properties of the joints were evaluated using optical microscopy and scanning electron microscopy (SEM). Static and fatigue tests were conducted on the welded joints. Effect of weld geometry and HAZ softening on fatigue performance including fatigue life, crack initiation site and propagation path of the joints will be analyzed.

In this study, fatigue performance of Gas Metal Arc Welded (GMAW) joint for 1.5 mm uncoated DP780 and 1.0 mm and aluminized coated boron (or USIBOR) steel was investigated. Metallurgical properties of DP780 to coated boron steel dissimilar steel lap joints were evaluated using optical microscopy. Microhardness traverse, static and fatigue tests were conducted on these joints. Finite element analysis (FEA) was used to identify the stress distribution of the weld joints with different stack-ups and at same loading conditions. It was found that position of the material (top or bottom in lap joint configuration) had a significant impact on fatigue performance of the dissimilar joint. The amount of heat introduced by welding to coated boron steel is also believed to be important to the fatigue performance of the dissimilar joints. The findings in this study can be used when aluminized boron steel is involved in dissimilar steel and dissimilar thickness GMAW lap joint design.

With the increasing demand for safety, energy saving and emission reduction, Advanced High Strength Steels (AHSS) have become very attractive materials for automobile makers. The usage of AHSS materials is projected to grow significantly in the next 5-10 years with new safety and fuel economy regulations. These new materials have significant manufacturing challenges, particularly for welding and stamping. Welding of AHSS remains one of the technical challenges in the successful application of AHSS in automobile structures, especially when durability of the welded structures is required. In this study, 2.0 mm uncoated DP600 and 2.0 mm uncoated boron (heat treated) steel lap joint configuration was investigated. Metallurgical properties of the DP600 to boron steel dissimilar steel lap joints were evaluated using optical microscopy. Static and fatigue tests were conducted on these joints.

Fuel economy and federal safety regulations are driving automotive companies to use Dual Phase and other Advanced High Strength Steels (AHSS) in vehicle body structures. Joining and assembly plays a crucial role in the selection of these steels. Specifications are available for the resistance spot welding (RSW) of lower strength sheet steels, covering many aspects of the welding process from the stabilization procedure to endurance testing. Currently, specifications in the automotive industry for RSW with AHSS are limited. It is well known that welding of a thickness ratio greater than 1:2 poses a challenge. To utilize thinner gauge AHSS panels on body-in-white, welding schedules to join the thin to thick sheet steel stack-up are needed. Most of the existing published work was conducted on uncoated sheets and welded to the same thickness.

There has been a substantial increase in the use of advanced high strength steel in automotive structures in the last few years. The usage of these materials is projected to grow significantly in the next 5-10 years with the introduction of new safety and fuel economy regulations. Advanced High Strength Steels (AHSS) are gaining popularity due to their superior mechanical properties, and downgage potential for mass avoidance, as compared to mild steels. These new materials also pose significant manufacturing challenges, particularly for welding and stamping. Proper understanding of the weldability of these materials is critical for successful application on future vehicle programs. Due to the high strength nature of AHSS materials, higher weld forces and longer weld times are needed to weld AHSS materials. In this paper, weld lobe development for various gages of Dual Phase 780 (DP780) steel is discussed.

The automotive industry is in constant pursuit of alternative materials and processes to address the ever changing needs of their customer and the environment. This paper presents findings from a study using a laser hybrid process (laser with MIG) to join aluminum-silicon coated boron steel (USIBOR). In this report the influence of heat from the laser hybrid welding process and its effect on the coated boron steel is discussed. In order to understand the affect from laser hybrid joining process, bead on plate experiments were conducted using 1.0 mm, 1.6 mm and 2.0 mm thick coupons. Further, two lap joint configurations were also investigated using the 1.6 mm and 2.0 mm thick coupons. Based on the test results, a significant reduction in tensile strength was observed at the Heat Affected Zone (HAZ).

There has been a substantial increase in the use of advanced high strength steel (AHSS) in automotive structures in the last few years. The usage of these materials is projected to grow significantly in the next 5–10 years with the introduction of new safety and fuel economy regulations. AHSS are gaining popularity due to their superior mechanical properties and use in parts for weight savings potential, as compared to mild steels. These new materials pose significant manufacturing challenges, particularly for welding and stamping. Proper understanding of the weldability of these materials is critical for successful application on future vehicle programs. Due to the high strength nature of AHSS materials, higher weld forces and longer weld times are often needed to weld these advanced steels.

There has been a substantial increase in the use of advanced high strength steel (AHSS) in automotive structures in the last few years. The usage of these materials is projected to grow significantly in the next 5-10 years with the introduction of new safety and fuel economy regulations. AHSS are gaining popularity due to their superior mechanical properties and use in parts for weight savings potential, as compared to mild steels. These new materials pose significant manufacturing challenges, particularly for welding and stamping. Proper understanding of the weldability of these materials is critical for successful application on future vehicle programs. Due to the high strength nature of AHSS materials, higher weld forces and longer weld times are often needed to weld these advanced strength steels.

With the increasing demand for safety, energy saving and emission reduction, Advanced High Strength Steels (AHSS) have become very attractive steels for automobile makers. The usage of AHSS steels is projected to grow significantly in the next 5-10 years with new safety and fuel economy regulations. These new steels have significant manufacturing challenges, particularly for welding and stamping. Welding of AHSS remains one of the technical challenges in the successful application of AHSS in automobile structures due to heat-affected zones (HAZ) at the weld joint. In this study Gas Metal Arc Welding (GMAW) of a lap joint configuration consisting of 1.0 mm Usibor® 1500 steel to uncoated Dual Phase 780 (DP780) steel was investigated. The objective of the study was to understand the wire feed rate (WFR) and torch (or robot) travel speed (TTS) influence on lap joint tensile strength.

There has been a substantial increase in the use of advanced high strength steel in automotive structures in the last few years. The usage of these materials is projected to grow significantly in the next 5–10 years with new safety and fuel economy regulations. These new materials have significant manufacturing challenges, particularly for welding and stamping. Proper understanding of the weldability of these materials is critical for successful application in future vehicle programs. This paper presents our production experience in use of DP600. Development work on the effect of weld tips on button size, and shrinkage voids due to different welding variables is discussed. The paper also provides recommendations from the current experimental knowledge base for applications on higher grades of steel (DP780 and beyond).

To reach safety, emissions, and cost objectives, manufacturers of automotive body structural and chassis components shape thin gauge, high strength steel tube with a bending, pre-forming and hydroforming process. Challenging grades and bend severity require a careful optimization of the bending procedure. A joint project between Ford and ArcelorMittal Tubular Products investigated suitable bending parameters for severe bends using commercially available thin-walled DP780 and HSLA350 tubes. This paper summarizes the measurement methods found to be capable of capturing small differences in bending formability and details the influence of bender variables such as boost, pressure die, center-line bend radius and bend angle on the wrinkling, thinning and springback of these tubes. As a result of this work, recommendations were made as to effective bender set-ups for these tubes.

To reach safety, emissions, and cost objectives, manufacturers of automotive body structural components shape thin gauge, high strength steel tube using a series of manufacturing steps that often include bending, preforming and hydroforming. Challenging grades and bend severity require a sensitive optimization of the tubular bending process. To this end, it is necessary to achieve an understanding of efficient measurement methods capable of capturing small differences in bending formability. In preparation for an optimization of a 90o bend using Dual Phase 780 (DP780) and High Strength Low Alloy (HSLA350) thin walled tube, the measurement techniques of three formability characteristics: thinning, strain, and final geometry were statistically evaluated. In addition, the difference in the bending behaviour of the two grades was evaluated.