Response of ultra-high strength quenched and tempered steel plates to heat

Abstract

Grade S690 has a much higher tensile strength than the common grades that is used in the industry. Due to this high strength, using S690 will promote the design of leaner structures with increased energy efficiency and easier transportation of the materials. However, the strength of the steel greatly decreases after being exposed to high temperatures. Therefore welding will also reduce the joints strength compared to the base metal. Furthermore, welding will cause the metal to be brittle and gain a lot of residual stress.

This report aims to investigate different conditions of post-weld heat treatment(PWHT) for S690 steels and whether it is effective in restoring the strength and ductility. Different welds with receiving different PWHT conditions will have its strength tested and compared.

There are 2 main segments in this report. The first one will be on the tensile test of different samples after they have been given different PWHT conditions. The results will be discussed in greater detail. The second part will be using the data gathered from the tensile tests to apply to a computer software that utilizes the Finite Element Method. A 3D model of a T-joint will be created and the weld will be given the properties of the samples from the first part by giving it tensile and ultimate stress and strain values obtained from the tensile tests.

In the 2 main segments, a comparison will be made to TMCP plates.