Microstructure and mechanical properties of high-strength steel welding consumables with a minimum yield strength of 1100 MPa

Abstract

Welded high-strength steel components have great potential for use in lightweight constructions or highly loaded structures. Welding of steels with a yield strength of more than 1100 MPa is particularly challenging because of the toughness requirements for the weld metal. Currently, a new generation of welding consumables with a minimum yield strength of 1100 MPa has been developed. Based on electron backscatter diffraction and atom probe tomography, a concept for toughening and strengthening of all-weld metal samples was deployed. Starting from a martensitic all-weld metal sample with an approximate yield strength of 1000 MPa, a reduction in manganese and silicon content resulted in a refined microstructure with a lower prior austenite grain size and effective grain size. Furthermore, a higher average grain boundary misorientation was measured, which influences the toughness positively. An addition of vanadium caused the formation of vanadium-rich clusters, which increased the strength of the all-weld metal significantly. With a combination of these two mechanisms, it was possible to produce an all-weld metal sample with the required yield strength of more than 1100 MPa and an acceptable toughness.

Influence of inhomogeneity on several length scales on the local mechanical properties in V-alloyed all-weld metal

“…The produced all-weld metal samples were martensitic and contained V(C,N) precipitates [4,13]. The purpose of this study is to demonstrate the existence of chemical and microstructural inhomogeneities in this type of martensitic multipass weld metal and to clarify their influence on the mechanical properties of the weld.…”

“…Currently, a V-alloyed welding consumable with a yield strength of 1100 MPa and a minimum impact energy of 47 J at − 20°C was developed [13]. The produced all-weld metal samples were martensitic and contained V(C,N) precipitates [4,13].…”

Analysis of Selected Properties of Welded Joints of the HSLA Steels

“…Haslberger et al [12] have presented a research of the multi-pass welded joints of the high-strength low-alloyed steel, done by the underwater local cavity welding and underwater dry welding techniques. The micro-hardness of the HAZ and fusion zone in the underwater local cavity welding specimen was higher than in the related zones in the underwater dry welding joint.…”

Influences of Thermomechanical Treatment and Nb Micro-alloying on the Hardenability of Ultra-High Strength Steels

“…The highest strength and proficient toughness as well as good weldability are realized with these steel grades. [7] This is accomplished by the systematic combination of an alloying and a rolling schedule in which the recrystallization processes are tuned to achieve a fine-grained austenitic microstructure prior to martensitic transformation. The influence of the condition of the prior austenite grain (PAG) on the properties of the emerging steel product has been investigated in depth.…”