Björk, T., Valkonen, I., Kömi, J., and Indren, H., "Capacity of a Welded Structure of Direct-Quenched Ultra-High-Strength Structural Steels," SAE Technical Paper 2014-36-0031, 2014, doi:10.4271/2014-36-0031.
The development of weldable high-strength and wear-resistant steels have made modern structures such as booms and mobile equipment possible. These sorts of novel and effective designs could not be constructed with traditional mild steel. Unfortunately, the use of these novel steels requires proper design, and there is no practical design code for these novel steels.This paper addresses stability issues, which are important considerations for designs with high-strength steels, and the properties of the heat-affected zone, which may require special attention.Fatigue design is also discussed in this paper, and the importance of the weld quality is highlighted, along with discussions on which details in the weld are the most important.By comparing the test results with the classical load limit solution, it is determined that full plastic capacity is reached and that the samples display good strain properties. Additionally, the reliability of the classical formulas is shown by comparing them to a recently proposed, novel formula.The fracture toughness of heat-affected zone is tested using the standard ASTM fracture mechanical testing. The testing indicates that direct-quenched steels also demonstrate good fracture properties in the weld heat-affected zone and provide good resistance against sudden, unexpected collapse.