Optimization Study of Post-Weld Heat Treatment for 12Cr1MoV Pipe Welded Joint

In order to clarify the role of different post-weld heat treatment processes in the manufacturing process, welding tests, post-weld heat treatment tests, and finite element analysis (FEA) are carried out for 12C1MoV steel pipes. The simulated temperature field and residual stress field agree well with the measured results, which indicates that the simulation method is available. The influence of post-weld heat treatment process parameters on residual stress reduction results is further analyzed. It is found that the post weld dehydrogenation treatment could not release residual stress obviously. However, the residual stress can be relieved by 65% with tempering treatment. The stress relief effect of “post weld dehydrogenation treatment + temper heat treatment” is same with that of “temper heat treatment”. The higher the temperature, the greater the residual stress reduction, when the peak temperature is at 650–750 °C, especially for the stress concentration area. The longer holding time has no obvious positive effect on the reduction of residual stress.

Quenching and tempering parameter on Indonesian hot rolled plate steel for armour steel

Armour steel is a high strength and hardness steel used to protect damage by an object, individual or vehicle from the direct pressure of projectile. This steel used for military and commercials equipment in Indonesia and produced out of hot rolled plate steel made by PT. Krakatau Steel (Persero) Cilegon, Banten, Indonesia. By using quench (with water sprayed) and temper heat treatment produced Quenched & Tempered Steels. The aim of the study to obtain optimum quenching and tempering parameter in hardness and impact energy of HRP Steel. Method of this study by optimizing austenite temperature; austenite holding time; temper temperatures; hardness and impact energy. The result of this study is austenite temperatures 900°C (held 45 minutes) and temper temperatures 125°C (held 45 minutes). Prediction of both hardness and impact energy is 569.96 HVN (536.00 BHN) and 30.50 J respectively.

Induction Hot Bending and Heat Treatment of 20” API 5L X80 Pipe

The present work discusses the effect of the induction hot bending process on the microstructure and the mechanical properties of an API 5L X80, 20” pipe produced by the UOE process. The key characteristic of the pipe was the manufacturing process of the steel plate, involving thermomechanical controlled rolling without accelerated cooling. The pipe bending was carried out applying local induction heating followed by water quenching and a further temper heat treatment which was applied to the curved section. The methodology of analysis compared the curved section with the original body pipe (tangent end), taking into account dimensional analysis, microstructural evaluation and mechanical tests which included Charpy-V impact, tensile and microhardness. A significant microstructural change and decrease, not only in the transition temperature, but also in the yield strength, occurred after induction bending. This reduction resulted in a tensile strength below the standard requirements. The subsequent tempering heat treatment applied to the curved section produced an increase in the yield strength to achieve the API 5L requirements for this class of steel.