Evaluation of Secondary Hardening and Microstructure in the Real T24 Steel Weld Joint

2015 ◽  
Vol 1111 ◽  
pp. 151-156
Author(s):  
Martin Sondel ◽  
Jaroslav Koukal ◽  
David Schwarz ◽  
Drahomir Schwarz
Keyword(s):  
Heat Treatment ◽  
Low Temperature ◽  
Weld Joint ◽  
Creep Resistance ◽  
Post Weld Heat Treatment ◽  
Secondary Hardening ◽  
The Real ◽  
Weld Joints ◽  
Heat Treated ◽  
Weld Heat

Development of new steels with higher creep resistance must be based on detailed knowledge of strengthening and degradation processes, structural stability at high temperature exposure and their welding. This paper is concerned with the real weld joint hardness and microstructure of progressive low alloy creep resistance T24 steel. These steel is widely used in many power-plant constructions all over the Europe. Welding the T24 steels components is one of the most important technological procedures. The aim of the performed investigation is to evaluate the hardness and microstructure in the heat affected zone (HAZ) and the weld metal. Results of the secondary hardening in the real weld joints after low temperature post weld heat treatment (460°C/48h) and without post weld heat treatment at service temperature are described in this paper. Obtained results are compared to the hardness values of the weld joint post weld heat treated at recommended temperature (740°C). The microstructure of the real weld joints was analysed by transmission electron microscopy (TEM) in order to identify minority phases - MX nanoparticles and/or coarse (M23C6) particles. Secondary hardening of the not heat treated and low temperature heat treated T24 weld joint was proved.

The Effect of Post Weld Heat Treatment on Mechanical Properties of Friction-Welded Alloy 718 and SNCRW Stainless Steel

2007 ◽  
Vol 26-28 ◽  
pp. 511-514 ◽  
Author(s):  
Nam Yong Kim ◽  
Jeoung Han Kim ◽  
Yu Sik Kong ◽  
Jong Won Yoon ◽  
Jong Taek Yeom ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Weld Joint ◽  
Friction Welding ◽  
Rotation Speed ◽  
Post Weld Heat Treatment ◽  
Alloy 718 ◽  
Temperature Range ◽  
Heat Treated ◽  
Weld Heat

The effect of post weld heat treatment on mechanical properties of friction welded Alloy 718 and SNCRW was investigated. Friction welding tests were carried out at a constant rotation speed and pressure. Optimum friction condition was found to be the friction pressure of 25kg/cm2, friction time of 40sec, upset pressure of 80 kg/cm2, and dwell time of 5sec. After friction welding tests, post weld heat treatments were performed in the temperature range of 500-900°C for 8hrs in order to investigate the microstructure and mechanical properties of weld joint. Specimens with the post weld heat treatment at 720°C for 8hrs show optimal mechanical properties. Residual stress of post weld heat treated specimens was measured to weld joint in the same temperature range. After friction welding tests on samples with a diameter of 80mm, tensile properties of post-weld-heat-treated and non-heat-treated samples were compared.

The Causes of Low Impact Strength of T23 Steel Weld Joints

2015 ◽  
Vol 226 ◽  
pp. 103-106
Author(s):  
Janusz Adamiec ◽  
Izabela Pikos ◽  
Michał Stopyra
Keyword(s):  
Heat Treatment ◽  
Impact Strength ◽  
Weld Metal ◽  
Post Weld Heat Treatment ◽  
Weld Joints ◽  
Heat Treated ◽  
Heat Treated Condition ◽  
The Impact ◽  
Welding Technique ◽  
Weld Heat

T23 is modern bainitic steel designed for use in supercritical boilers. According to producer’s data weldability of this steel is good enough to avoid post-weld heat treatment. However, some of the T23 weld joints in as-welded condition have not met the minimal ductility requirement. The impact test revealed significant differences between the joints in as-welded and heat treated condition. Metallographic and fractographic examinations have been conducted in order to explain those differences. The specimens with low impact strength were characterized by brittle fracture and non-tempered martensite presence in weld metal. It was concluded that avoiding formation of disadvantageous structure in weld metal requires conducting of post weld heat treatment or applying multi-pass welding technique with annealing run.

Effect of post weld heat treatment and welding parameters on mechanical and corrosion characteristics of friction stir welded aluminium alloy AA2014-T6

2019 ◽  
Vol 43 (2) ◽  
pp. 230-236
Author(s):  
Ashok S. Kannusamy ◽  
Ravindran Ramasamy
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Welding Process ◽  
Post Weld Heat Treatment ◽  
Welding Parameters ◽  
Friction Stir ◽  
Heat Treated ◽  
Ageing Period ◽  
Weld Heat

This paper addresses the effect of post weld heat treatment methods on the mechanical and corrosion characteristics of friction stir welded aluminum alloy AA2014-T6. Aluminum alloy AA2014 is mainly used in applications that demand high strength to weight ratios, such as aerospace, marine, and industrial applications. In this work, AA2014-T6 plates of 6 mm thick were butt welded using a tool with a square profile. Tensile strength, hardness, and corrosion characteristics were compared between the samples as welded and post weld heat treated. Welded samples that were heat treated for a shorter ageing period (8 h) showed improved tensile strength irrespective of welding process parameters, compared to as-welded samples. The samples heat treated for a longer ageing period (9 h) showed a decline in tensile strength for low tool rotation speed. Hardness increased in welded samples heat treated for 8 h. Welded samples heat treated for 9 h show high passivity in corrosion media.

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.

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

2018 ◽  
Vol 37 (7) ◽  
pp. 649-654 ◽  
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.

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.

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