Dramatically enhanced impact toughness in welded 10%Cr rotor steel by high temperature post-weld heat treatment

2014 ◽  
Vol 92 ◽  
pp. 149-158 ◽  
Author(s):  
Fenggui Lu ◽  
Peng Liu ◽  
Huijun Ji ◽  
Yuming Ding ◽  
Xiaojin Xu ◽  
...  
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Impact Toughness ◽  
Post Weld Heat Treatment ◽  
Rotor Steel ◽  
Weld Heat

scholarly journals Influence of post weld heat treatment for weld joint of P355GH

2018 ◽  
Vol 247 ◽  
pp. 00038
Author(s):  
Sławomir Parzych ◽  
Rafał Dziurka
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Quality Control ◽  
High Temperature ◽  
Weld Joint ◽  
Post Weld Heat Treatment ◽  
Microstructure And Properties ◽  
Welding Method ◽  
Welding Procedure ◽  
Weld Heat

From steel designed to work under pressure and exposed to high temperature apart from the good weldability, good mechanical properties are required. The guidelines set by the regulations require post welding heat treatment above 35mm thick. An important factor affecting the microstructure and properties of the joint made of thick-walled elements is heat treatment after welding. All welding operations must be properly planned before performing welding work. Welding procedure specification (WPS) is a document describing these operations, it is essential for proper determining of basics in planning welding operations and quality control in welding. The purpose of this paper is to compare the properties of joints made by 121 welding method in combination with and without post welding heat treatment.

The Effect of PWHT on the Material Properties and Micro Structure in Inconel 625 and Inconel 725 Buttered Joints

2003 ◽  
Author(s):  
Vigdis Olden ◽  
Per Egil Kvaale ◽  
Per Arne Simensen ◽  
Synno̸ve Aaldstedt ◽  
Jan Ketil Solberg
Keyword(s):  
Heat Treatment ◽  
Impact Toughness ◽  
Post Weld Heat Treatment ◽  
Fusion Line ◽  
Coarse Grained ◽  
Inconel 625 ◽  
Micro Structure ◽  
Mixed Zone ◽  
Heat Treated ◽  
Weld Heat

This report describes investigations performed on as welded and post weld heat treated samples of AISI 8630 steel, buttered with Inconel 625 and Inconel 725. The investigations have focused on the properties and microstructure in the partial mixed zone between the buttering and the steel before and after post weld heat treatment. The samples were heat treated for 4 1/2 hours at 640°C, 665° and 690°C and investigated with respect to mechanical properties and microstructure near the fusion line. A range of testing and analyses were performed including notch impact toughness testing, identification of fracture initiation and propagation in impact specimens, hydrogen measurements, examination of the micro structure in steel and Inconel using light microscope, hardness testing and electron micro-probe analysis of the alloying elements across the fusion line. Additional investigations in TEM on samples from an actual joint, post weld heat treated at 665°C were also performed. The results show that post weld heat treatment at 665°C and 690°C reduced the impact toughness in coarse grained heat affected zone, caused by decarburisation, ferrite formation and grain growth. The partially mixed zone (5–10μm) of the Inconel buttering, gained partly extremely high hardness caused by carbon enrichment, reaustenitization and formation of virgin martensite. As welded samples gave more favorable properties and microstructure than the post weld heat treated ones.

Microstructural Evolution and Resulting Mechanical Properties of Weld Joints upon Flux Cored Arc Welding and Post-Weld Heat Treatment

2009 ◽  
Vol 283-286 ◽  
pp. 439-446 ◽  
Author(s):  
Hui Yu ◽  
Kee Sam Shin ◽  
Ji Ling Dong ◽  
Dae Hwang Yoo ◽  
Woong Lee ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Impact Toughness ◽  
Arc Welding ◽  
Compositional Analysis ◽  
Post Weld Heat Treatment ◽  
Grain Structure ◽  
Automatic Welding ◽  
Weld Joints ◽  
Flux Cored Arc Welding ◽  
Weld Heat

The objective of this study is to determine the mechanism of the dramatic increase of impact toughness at low temperatures after post-weld heat treatment on weld joints. In this study, weld joints using two semi-automatic welding consumables were fabricated by flux cored arc welding with subsequent PWHT at 660°C for 65 min and 195 min, respectively. Tests of the tensile and yield strength, microhardness and impact toughness, were carried out. The microstructure was inspected by optical, scanning electron, and transmission electron microscopy in addition to compositional analysis using energy dispersive spectrometry. PWHT was observed to result in grain coarsening, sub-grain structure formation and decrease of the dislocation density. The increase of impact toughness is attributed to the relieved thermal stress, the inclusions and precipitations, softening of the structure, dislocation recovery and sub-grain structure.

Friction Stir Welding of Al-Li AA2199: Parameters, Precipitates and Post Weld Heat Treatment

2011 ◽  
Vol 409 ◽  
pp. 853-858
Author(s):  
Rosen Ivanov ◽  
Julien Boselli ◽  
Diana Denzer ◽  
Daniel Larouche ◽  
Raynald Gauvin ◽  
...  
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Friction Stir Welding ◽  
Weld Zone ◽  
Base Material ◽  
Post Weld Heat Treatment ◽  
Second Phase ◽  
Friction Stir ◽  
Tool Rotation ◽  
Weld Heat

The aerospace industry strives to develop materials allowing an increase in payload and reducing fuel consumption. Al-Li alloys, with their low density and high strength are currently in use for such applications and have potential for additional applications. When compared to composites, utilizing Al-Li alloy products is cost effective for aerospace companies as they do not need to redesign pre-existing fabrication facilities. The joining of these alloys by conventional methods is limited by segregation of alloying elements and the formation of oxides during high temperature exposure. This study focuses on solid state joining method that has the potential to generate low heat and be defect free - Friction Stir Welding (FSW). AA2199 sheets were joined by FSW. Process variables included table force, tool rotation speed and weld travel speed. A post weld heat treatment (PWHT) was applied to improve the mechanical properties by precipitation of strengthening phases. An increase in hardness of the weld zone from 95HV to 125HV upon PWHT was recorded for selected welding conditions. The type and morphology of second phase precipitates is deemed responsible for this effect. It is suggested that the high temperature and high strain levels characteristic of welds with fast tool rotation allow for the dissolution of precipitates during welding. The re-precipitation of these second phases during PWHT allowed the welds to recover strength to the level of the base material.

Weldability Studies of AISI 409 Ferritic Stainless Steel Thick Plates Using Electron Beam Welding Process

2021 ◽  
Vol 11 (2) ◽  
pp. 55-67
Author(s):  
Akash Doomra ◽  
Beant Singh ◽  
Sandeep Singh Sandhu
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Electron Beam ◽  
Impact Toughness ◽  
Base Metal ◽  
Electron Beam Welding ◽  
Weld Zone ◽  
Welding Process ◽  
Post Weld Heat Treatment ◽  
Weld Heat

In the present research, attempts have been made to weld 18 mm thick AISI 409 ferritic steel plate in a single pass with electron beam welding process. The welded joint was investigated for macrostructure, microstructural, microhardness, impact toughness, and tensile strength. The coarse ferritic grains of base metal were converted into fine equiaxed and columnar grains in the weld zone. The microhardness results revealed that for fusion zone and heat affected zone had 28% and 41% higher microhardness than the base metal. Further, post weld heat treatment at 550ºC/75 minutes resulted in 5% rise in ultimate tensile strength, 10% rise in yield strength, and 31% rise in impact toughness as compared to as welded specimens. The fractography of impact and tensile specimens revealed brittle mode of fracture and changed to ductile mode after post weld heat treatment.

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