Effect of Long-Term Post-Weld Heat Treatment on the Microstmeture and Mechanical Properties of P91 Weld Metal

4330V is a high strength, high toughness, heat treatable low alloy steel for application in the oil, gas and aerospace industries. It is typically used for large diameter drilling parts where high toughness and strength are required. The research describes the effect of preheat temperature, interpass temperature, heat input, and post weld heat treatment on strength, hardness, toughness, and changes to microstructure in the weld joint. Welding with the lower heat input and no post weld heat treatment resulted in optimal mechanical properties in the weld metal. Austempering at 400 °C resulted in optimal mechanical properties in the HAZ. Increasing preheat and interpass temperature from 340 °C to 420 °C did not improve Charpy V-notch values or ultimate tensile strength in the weld metal or heat affected zones. The higher temperature increased the width of the heat affected zone. Austempering at 400 °C reduced HAZ hardness to a level comparable to the base metal. Both tempering and austempering at 400 °C for 10 hours reduced toughness in the weld metal.

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Effect of Post Weld Heat Treatment on Weld Hardness Quality of P91 Welded Pipes

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.799-800.377 ◽

2015 ◽

Vol 799-800 ◽

pp. 377-381

Author(s):

Mohd Amin Abd Majid ◽

Muhammad Sarwar

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Residual Stresses ◽

Weld Metal ◽

Welded Joint ◽

Post Weld Heat Treatment ◽

Bead Geometry ◽

Construction Sites ◽

Weld Heat

Quality of a weld produced is generally evaluated by different parameters such as weld size, bead geometry, deposition rate, hardness and strength. A common problem that has been faced at the construction sites is to obtain a good welded joint having the required strength with minimal detrimental residual stresses to avoid any premature cracking due to high variation of hardness. In order to address this issue and to attain good weld quality, this study has been made to comprehend the effect of the post weld heat treatment on P91 material welds produced by TIG welding. Findings from the studies indicate that the PWHT has significant influence on the weld hardness of Alloy Steel-A335 P91 pipes. It is eminent that during cooling, after welding of P91, quenched martensite was formed in the HAZ that results in an increased hardness to an undesirable level of more than 250HB. PWHT at temperature of 760°C for 2 hours has good influence on mechanical properties as the hardness decreases and turns out to be uniformly distributed. If the PWHT is correctly carried out, the hardness of parent metals, heat affected zones and weld metal can be brought into the required limits to avoid any premature cracking due to high variation of hardness.

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Post-weld Heat Treatment and Groove Angles Affect the Mechanical Properties of T92/Super 304H Dissimilar Steel Weld Joints

High Temperature Materials and Processes ◽

10.1515/htmp-2016-0261 ◽

2018 ◽

Vol 37 (7) ◽

pp. 649-654 ◽

Cited By ~ 1

Author(s):

Wang Shuo ◽

Wei Limin ◽

Cheng Yi ◽

Tan Shuping

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Weld Metal ◽

Arc Welding ◽

Post Weld Heat Treatment ◽

Steel Weld ◽

Dissimilar Weld ◽

Weld Joints ◽

Gas Tungsten Arc ◽

Weld Heat

AbstractThe microstructures and mechanical properties of dissimilar weld joints between T92 and Super 304H steels were investigated. Dissimilar weld joints with four groove angles were constructed using gas tungsten arc welding. The results showed that post-weld heat treatment improved the mechanical properties of the dissimilar weld joints. The optimal groove angle for T92/Super 304H dissimilar weld joints was found to be 20°, considering mechanical properties. Furthermore, the transformation from equiaxed dendrites to columnar dendrites was observed in the weld metal. Epitaxial growth and delta ferrites were found around the fusion line between the Super 304H and the weld metal.

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Effects of post weld heat treatment (PWHT) on mechanical properties of C-Mn weld metal: Experimental observation and microstructure-based simulation

Materials Science and Engineering A ◽

10.1016/j.msea.2017.12.006 ◽

2018 ◽

Vol 712 ◽

pp. 430-439 ◽

Cited By ~ 7

Author(s):

Chengze Zhang ◽

Shihua Yang ◽

Baoming Gong ◽

Caiyan Deng ◽

Dongpo Wang

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Weld Metal ◽

Experimental Observation ◽

Post Weld Heat Treatment ◽

Weld Heat

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On the impact of post weld heat treatment on the microstructure and mechanical properties of creep resistant 2.25Cr–1Mo–0.25V weld metal

Journal of Materials Science ◽

10.1007/s10853-021-06618-2 ◽

2021 ◽

Author(s):

Hannah Schönmaier ◽

Christian Fleißner-Rieger ◽

Ronny Krein ◽

Martin Schmitz-Niederau ◽

Ronald Schnitzer

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Weld Metal ◽

Elevated Temperatures ◽

Stress Rupture ◽

Pressure Vessels ◽

Post Weld Heat Treatment ◽

Microstructure And Mechanical Properties ◽

The Impact ◽

Weld Heat

AbstractCreep resistant low-alloyed 2.25Cr-1Mo-0.25V steel is typically applied in hydrogen bearing heavy wall pressure vessels in the chemical and petrochemical industry. For this purpose, the steel is often joined via submerged-arc welding. In order to increase the reactors efficiency via higher operating temperatures and pressures, the industry demands for improved strength and toughness of the steel plates and weldments at elevated temperatures. This study investigates the influence of the post weld heat treatment (PWHT) on the microstructure and mechanical properties of 2.25Cr-1Mo-0.25V multi-layer weld metal aiming to describe the underlying microstructure-property relationships. Apart from tensile, Charpy impact and stress rupture testing, micro-hardness mappings were performed and changes in the dislocation structure as well as alterations of the MX carbonitrides were analysed by means of high resolution methods. A longer PWHT-time was found to decrease the stress rupture time of the weld metal and increase the impact energy at the same time. In addition, a longer duration of PWHT causes a reduction of strength and an increase of the weld metals ductility. Though the overall hardness of the weld metal is decreased with longer duration of PWHT, PWHT-times of more than 12 h lead to an enhanced temper resistance of the heat-affected zones (HAZs) in-between the weld beads of the multi-layer weld metal. This is linked to several influencing factors such as reaustenitization and stress relief in the course of multi-layer welding, a higher fraction of larger carbides and a smaller grain size in the HAZs within the multi-layer weld metal.

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