Effect of Welding Consumables on Static and Dynamic Properties of Representative Welded Joints for Chassis Structure

Automotive suspension system forms the basis for the design of vehicle with durability, reliability, dynamics and NVH requirements. The automotive suspension systems are exposed to dynamic and static loads which in turn demands the highest integrity and performance against fatigue based metallic degradation. The current focus in automotive industry is to reduce the weight of the automotive parts and components without compromising with its static and dynamic mechanical properties. This weight reduction imparts fuel efficiency with added advantages. High-Strength Low Alloy steel (HSLA) offers optimum combination of ductility, monotonic and cyclic mechanical properties. Furthermore, welding processes offer design flexibility to achieve robust and lightweight designs with high strength steels. However, welding process has to be established to get optimum benefits of high strength steels with minimal adverse effects and deterioration of the static and dynamic mechanical properties of the weldments.

In current work, effect of welding parameters, weld design and welding consumables with different chemistries and mechanical properties were studied on the static and dynamic strength of weld joints. High strength steel plates were welded together with Butt Joint and “T” Joint configurations. The welded joints were undertaken for metallurgical studies to understand phase formation and local metallurgical changes with respect to hardness and microstructure. Butt joints were evaluated under static tensile load. Welded “T” joints were used to simulate dynamic loads for a typical fatigue cycle. It was observed that static properties depends on welding consumables whereas dynamic properties are more related to joint geometry and weld bead shape.