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.

scholarly journals The Influence of the Post-Weld Heat Treatment on the Microstructure of Inconel 625/Carbon Steel Bimetal Joint Obtained by Explosive Welding

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 246 ◽  
Author(s):  
Robert Kosturek ◽  
Marcin Wachowski ◽  
Lucjan Śnieżek ◽  
Michał Gloc
Keyword(s):  
Heat Treatment ◽  
Diffusion Zone ◽  
Explosive Welding ◽  
Stress Relief ◽  
Scanning Transmission Electron Microscope ◽  
Post Weld Heat Treatment ◽  
Inconel 625 ◽  
Scanning Transmission ◽  
Inconel 625 Alloy ◽  
Weld Heat

Inconel 625 and steel P355NH were bonded by explosive welding in this study. Explosively welded bimetal clad-plate was subjected to the two separated post-weld heat treatment processes: stress relief annealing (at 620 °C for 90 min) and normalizing (at 910 °C for 30 min). Effect of heat treatments on the microstructure of the joint has been evaluated using light and scanning electron microscopy, EDS analysis techniques, and microhardness tests, respectively. It has been stated that stress relief annealing leads to partial recrystallization of steel P355NH microstructure in the joint zone. At the same time, normalizing caused not only the recrystallization of both materials, but also the formation of a diffusion zone and precipitates in Inconel 625. The precipitates in Inconel 625 have been identified as two types of carbides: chromium-rich M23C6 and molybdenum-rich M6C. It has been reported that diffusion of alloying elements into steel P355NH takes place along grain boundaries with additional formation of voids. Scanning transmission electron microscope observation of the grain microstructure in the diffusion zone shows that this area consists of equiaxed grains (at the side of Inconel 625 alloy) and columnar grains (at the side of steel P355NH).

scholarly journals EFFECT OF WELDING SEQUENCE ON MULTI PASS TEMPER BEAD WELDING JOINT OF PT .INKA BOGIE LRT ON DISTORCTION, MICRO STRUCTURE AND HARDNESS

2019 ◽  
Vol 11 (2) ◽  
pp. 103-111
Author(s):  
Moh M Munir ◽  
Mukhlis Mukhlis ◽  
Imam Khoirul R ◽  
Hendri B ◽  
M Syaiful A ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Post Weld Heat Treatment ◽  
Micro Structure ◽  
Welding Joint ◽  
Welding Sequence ◽  
Round Bar ◽  
Weld Heat

Bogie kereta api merupakan salah satu bagian yang sangat penting, karena bogie menahan beban yang ada pada suatu gerbong kereta api. Karena sifatnya yang sangat penting maka bogie kereta api harus memiliki sifat dan kekuatan yang baik. Bogie hasil proses fabrikasi dengan pengelasan, memerlukan proses annealing untuk mereduksi tegangan sisa yang terjadi. Proses annealing atau Post Weld Heat Treatment tersebut membutuhkan furnace yang besar, energi listrik yang besar, dan tentunya biaya jadi lebih mahal. Pada penelitian ini,   dilakukan alternative  proses  pengelasan dengan teknik  Temper bead welding, pada sambungan frame bogie plate to plate dan plate to round bar. Selain itu juga melakukan proses Post Weld Heat Treatment pada sambungan plate to plte, dan sequence of welding pada sambungan plate to round bar. Hasil penelitian menunjukkan, bahwa proses Temper bead welding yang dilakukan terhadap proses fabrikasi joint bogie LRT plate to plate dan joint plate to round bar, dapat menurunkan nilai kekerasan, namun belum menunjukkan perbedaan yang signifikan. Sedangkan proses Temper bead welding dapat menghasilkan distorsi yang paling kecil pada bogie LRT. Hasil pengukuran distrosi menujukan pengelasan sequence B menghasilkan distorsi paling besar, sedangkan variasi distorsi terkecil adalah varisi sequence C dengan temper bead welding.

scholarly journals The Influence of the Post Weld Heat Treatment on the Microstructure of Inconel 625/Carbon Steel Bimetal Joint Obtained by Explosive Welding

2018 ◽  
Author(s):  
Robert Kosturek ◽  
Marcin Wachowski ◽  
Lucjan Śnieżek ◽  
Michał Gloc
Keyword(s):  
Heat Treatment ◽  
Electron Microscope ◽  
Diffusion Zone ◽  
Scanning Transmission Electron Microscope ◽  
Post Weld Heat Treatment ◽  
Inconel 625 ◽  
Joint Zone ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Weld Heat

In this investigation steel P355NH has been successfully cladded with Inconel 625 through the method of explosive welding. Explosively welded bimetal clad-plate was subjected to the two separated post weld heat treatment processes: stress relief annealing (at 620oC for 90 minutes) and normalizing (at 910oC for 30 minutes). In order to analyze the microstructure of the joint in the as-welded state and to investigate the influence of the post weld heat treatment on it, the light and scanning electron microscope observations and microhardness analysis have been performed. The examination of the diffusion zone microstructure has been performed by using the scanning transmission electron microscope. It was stated that obtained joint has characteristic wavy-shape geometry with the presence of the melted zones and severe deformed grains of both joined materials. Strain hardening of the materials in joint zone was established with microhardness analysis. In both of the heat treatments the changes in the grain structure have been observed. The normalizing heat treatment has the most significant impact on the microstructure of the joint as well as the concentration of the chemical elements in the joint zone. It was reported that due to normalizing the diffusion zone has been formed together with precipitates in the joint zone. The analysis of the diffusion zone images leads to the conclusion that the diffusion of alloying elements from Inconel 625 to steel P355NH takes place along the grain boundaries with additional formation of the voids in this area. The precipitates in Inconel 625 in the joint zone are two type of carbides – chromium-rich and molybdenum-rich. Scanning transmission electron microscope observation of the grain microstructure in the diffusion zone shows that this area consists of equiaxed grains (from the side of Inconel 625 alloy) and columnar grains (from the side of steel P355NH).

scholarly journals Optimization of PWHT of Simulated HAZ Subzones in P91 Steel with Respect to Hardness and Impact Toughness

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1215 ◽  
Author(s):  
Gorazd Lojen ◽  
Tomaž Vuherer
Keyword(s):  
Impact Toughness ◽  
Elevated Temperatures ◽  
Thermal Power ◽  
Post Weld Heat Treatment ◽  
Coarse Grained ◽  
Target Range ◽  
Fine Grained ◽  
Creep Resistant Steels ◽  
The Impact ◽  
Weld Heat

Appropriate post weld heat treatment (PWHT) is usually obligatory when creep resistant steels are welded for thermal power plant components that operate at elevated temperatures for 30-40 years. The influence of different PWHTs on the microstructure, hardness, and impact toughness of simulated heat affected zone (HAZ) subzones was studied. Thereby, coarse grained HAZ, two different fine grained HAZ areas, and intercritical HAZ were subjected to 20 different PWHTs at temperatures 740–800 °C and durations 0.5–8 h. It was found that the most commonly recommended PWHT, of 3 h or less at 760 °C, is insufficient with respect to the hardness and impact toughness of coarse grained HAZ. To obtain a Vickers hardness ≤ 265 HV and impact toughness at least equal to the impact toughness of the base metal (192 J) in the coarse grained HAZ, it took 8 h at 740 °C, 4 h at 760 °C, more than 1 h at 780 °C, and 0.5 h and 800 °C. Even after 8 h at 800 °C, mechanical properties were still within the target range. The most recommendable post weld heat treatments at 780 °C for 1.2–2 h or at 760 °C for 3–4 h were identified. All specimens subjected to these treatments exhibited appropriate hardness, impact toughness, and microstructure.

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.

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.

Post-Weld Heat Treatment Stress Relaxation in Zircaloy 4 Plasma Welds

2006 ◽  
Vol 524-525 ◽  
pp. 491-496 ◽  
Author(s):  
Javier R. Santisteban ◽  
L. Fernández ◽  
H. Corso ◽  
R.L. Martínez ◽  
L. Boccanera ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Room Temperature ◽  
Longitudinal Direction ◽  
Post Weld Heat Treatment ◽  
Steady Increase ◽  
Compressive Stresses ◽  
Heat Treated ◽  
Residual Strains ◽  
Weld Heat

We have studied the effect of a post-weld heat treatment on plasma arc welds on Zircaloy 4 plates. The samples consist of two 100 mm long, 50 mm wide, and 6.25 mm thick plates, welded along the rolling (longitudinal) direction. The heat-treatment consisted of a steady increase in temperature from room temperature to 450oC over a period of 4.5 hours; followed by cooling with an equivalent cooling rate. Residual strains and stresses along the longitudinal, transverse and normal directions on an as-welded and a heat-treated specimen were measured by neutron diffraction on the ENGIN-X beamline at the Isis Facility, Rutherford Laboratory, UK. Peak tensile stresses of (105±25) MPa were found in the as-welded specimen, which were reduced to (70±20) MPa after the heat-treatment. Thermal compressive stresses of (-80±20) MPa were found along the normal direction, which were not affected by the heat treatment. The use of a full-pattern Rietveld refinement for the determination of bulk strains in Zircaloy specimens is also discussed.

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

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.

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