Welding of Ultra High Strength Steels

Abstract

The ongoing need to reduce the weight of products while increasing strength has resulted in new generation steel manufacturing using special heat treatments to produce High Strength Steels (HSS) and Ultra High Strength Steels (UHSS) with up to 1700 MPa tensile strength. The high strength level of these steels makes it possible to produce structures with a considerable weight and cost reduction, and such steels have been adopted in the automotive industry and for mobile heavy equipment. Welding of UHSS is, however, not without its complications and welding processes for these steels need careful attention. For instance, their high susceptibility to cracking and Heat Affected Zone (HAZ) softening are risks that need to be borne in mind when choosing welding parameters. This research work discusses the difficulties and challenges of successful welding of UHSS. Common welding methods used in welding of UHSS are briefly reviewed to gain a better understanding of the effects of different welding parameters and methods. The paper finds that UHSS can be satisfactorily welded with laser welding, electron beam welding, resistance welding, and conventional arc welding methods, but the quality of the weld is dependent on appropriate control of several parameters and variables of the welding processes.

Weldability of cold-formed high strength and ultra-high strength steels

“…To benefit from full potentials of HSSs and UHSSs and provide designers with more freedom, it is usually crucial to weld these steels. Thus, welding HSSs and UHSSs, especially by laser welding (LW) and gas-metal arc welding (GMAW), has been the subject of numerous studies [7]. In addition, weldability of these steels was investigated using various welding processes (including LW [8][9][10], ultra-narrow gap laser welding [11,12], tungsten inert gas welding [13,14], GMAW [12], and hybrid welding [15]) under different conditions (such as dissimilar welding positions [9] or dissimilar joints [16]).…”

Optimizing process parameters for joint strength efficiency improvement in friction stir welding of polycarbonate sheets

“…Quality can be specified as the degree of fitness for use as provided by the manufacturer whereas weld quality indicates the working efficiency in the service lifespan in different engineering applications [1]. In recent years, the polymers and polymeric materials like acrylonitrile butadiene styrene, polypropylene and polycarbonate are found to be highly popular in diversified industrial applications due to light‐weight and design flexibility with low processing cost [2]. However, the joining of polymers is a challenging task due to its poor thermal properties such as low melting temperature and low thermal conductivity which are responsible for poor weldability.…”

Fatigue strength degradation of thermomechanically rolled high strength steels welds

“…Furthermore, these hollow sections are critical for energy absorbent parts in contemporary automotive applications, where welding is still the most common joining method. Their increasing application is essential for the design of construction to increase the strength to weight ratio and at maintain or even improve safety standards, i.e., for automotive structures, trucks, cranes and ships [1,2].…”