scholarly journals Narrow Gap MAG Welding and Joint Performance Analysis of 25Cr2NiMo1V Thick Plate

2022 ◽  
Vol 2160 (1) ◽  
pp. 012022
Author(s):  
Xiaoyan Qian ◽  
Xin Ye ◽  
Xiaoqi Hou ◽  
Fuxin Wang ◽  
Shaowei Li ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Ductile Fracture ◽  
Impact Energy ◽  
Welded Joint ◽  
Fusion Line ◽  
Coarse Grained ◽  
Mag Welding ◽  
Rotor Steel ◽  
Narrow Gap ◽  
The Impact

Abstract The narrow gap MAG welding system was used to successfully weld the 50mm thick butt joint of 25Cr2NiMo1V rotor steel. After 15-layer bead welding, heat treatment is performed on the welded joint. Compare the changes in the microstructure, tensile strength and impact energy of the welded joints and the heat-treated joints at 580°C (20h). The results show that after the heat treatment of the structure, the side lath ferrite in the coarse-grained region grows up, and the eutectoid ferrite grows up in the fine-grained region first. The strength of the welded joint is about 605MPa, and the fracture is characterized by ductile fracture. After heat treatment at 580°C (20h), the strength is about 543MPa, the fracture is characterized by ductile fracture, and there are also a large number of discontinuous small surface platforms, and the characteristic of brittle fracture appears slightly. The impact energy of the weld center of the welded joint is about 141J, the fusion line area is about 113J, and the toughness of the fusion line is slightly lower than that of the weld center. After heat treatment, the impact energy at the center of the weld is about 183J, the fusion line area is about 95J, the toughness of the weld center increases, and the toughness of the fusion line decreases.

scholarly journals Effect of 580 °C (20 h) Heat Treatment on Mechanical Properties of 25Cr2NiMo1V Rotor-Welded Joints of Oscillating Arc (MAG) Narrow Gap Thick Steel

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4498
Author(s):  
Xiaoyan Qian ◽  
Xin Ye ◽  
Xiaoqi Hou ◽  
Fuxin Wang ◽  
Shaowei Li ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Brittle Fracture ◽  
Impact Energy ◽  
Fusion Line ◽  
Tensile Fracture ◽  
Rotor Steel ◽  
Narrow Gap ◽  
Heat Treated ◽  
Ductile Fractures ◽  
The Impact

The thick plate narrow gap welding of 25Cr2NiMo1V rotor steel is achieved by metal active gas arc welding, in which the weld gap was 18.04–19.9 mm. After welding, the weldment was heat treated at 580 °C (20 h). The impact and tensile properties in the as-welded and heat-treated were studied. The results show that after heat treatment, the coarse carbides in the center of the weld were transformed into fine granular carbides distributed along the grain boundaries, and the quantity of carbide precipitates in the weld near the fusion line was reduced. The tensile fracture mode changed from a ductile fracture to a combination of brittle and ductile fractures, and the tensile strength of the weld metal changed from 605 MPa to 543 MPa. After heat-treated, the radiation zone of the weld center changed from a brittle fracture to a combination of brittle and ductile fractures, and the impact energy changed from 141 J to 183 J; the characteristics of the brittle fracture in the radial zone of the fusion line were more obvious, and the impact energy changed from 113 J to 95 J. Therefore, after heat treatment, the toughness of the welded metal was improved, without reducing the strength and hardness of the welded metal to a large extent.

Investigation on Impact Energy of S30403 Austenitic Stainless Steel at Different Temperatures

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Zhiwei Chen ◽  
Caifu Qian ◽  
Guoyi Yang ◽  
Xiang Li
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Cross Section ◽  
Test Temperature ◽  
Impact Energy ◽  
Welded Joint ◽  
Charpy Impact ◽  
Base Plate ◽  
Charpy Impact Energy ◽  
The Impact

In this paper, a series of impact tests on S30403 austenitic stainless steel at 20/−196/−269 °C were performed to determine the effects of cryogenic temperatures on the material properties. Both base plate and welded joint including weld and heat-affected zone were tested to obtain the Charpy impact energy KV2 and lateral expansion rate at the cross section. It was found that when the test temperature decreased from 20 °C to −196 °C or −269 °C, both the Charpy impact energy KV2 at the base plate and welded joint decreased drastically. Specifically, the impact energy KV2 decreased by 20% at the base plate and decreased by 54% at the welded joint from 20 °C to −196 °C, but the impact energy of base plate and welded joint did not decrease, even increased when test temperature decreased from −196 °C to −269 °C. Either at 20 °C or −196 °C, the impact energy KV2 with 5 × 10 × 55 mm3 specimens was about 0.53 times that of the 7.5 × 10 × 55 mm3 specimens, much lower than 2/3, the ratio of two specimens’ cross section areas.

Microstructures and Properties of Ultra-Narrow-Gap Multi-Pass Welded Joint of 50 mm Turbine Rotor Steel by Laser Welding with Filler Wire

2015 ◽  
Vol 42 (2) ◽  
pp. 0203007
Author(s):  
赵勇 Zhao Yong ◽  
王清曌 Wang Qingzhao ◽  
黄坚 Huang Jian ◽  
吴毅雄 Wu Yixiong
Keyword(s):  
Laser Welding ◽  
Welded Joint ◽  
Turbine Rotor ◽  
Rotor Steel ◽  
Filler Wire ◽  
Narrow Gap

Mechanical Properties of Girth Weld with Different Butt Materials Severed for Natural Gas Station

2019 ◽  
Vol 944 ◽  
pp. 821-827
Author(s):  
Jun Jie Ren ◽  
Wei Feng Ma ◽  
Xue Liang He ◽  
An Qi Chen ◽  
Jin Heng Luo ◽  
...  
Keyword(s):  
Impact Toughness ◽  
Wall Thickness ◽  
Impact Energy ◽  
Weld Seam ◽  
Coarse Grained ◽  
Lower Grade ◽  
Straight Pipe ◽  
Bending Load ◽  
Girth Welds ◽  
The Impact

Weld samples imitating the inservice girth welds in station (L245 straight pipe jointed to WPHY-70 tee joint and L415MB straight pipe jointed to WPHY-80 tee joint) were prepared. Tensile, bending, impact toughness and hardness of the joints were investigated. Results show that under tensile or bending load, failure occurred from the side with lower grade and smaller wall thickness. Relatived to the lower grade side, the weld seam is strong match. Significant change of impact toughness can be found in weld seam center and the heat affected zones (HAZ). The impact energy of seam center is the lowest in the weld joint. The impact energy show a trend of increase from seam center to base metal. In HAZ zone, impact toughness of the fusion line is the lowest. Impact toughness of higher grade side is higher than that of the lower grade side. Hardness of positions in HAZ zones are different distinctly. From coarse grained region to fine grained region, the hardness decrease. For the in-station girth welds jointed with different materials, lower grade and samller wall thickness side should be intensive monitored.

scholarly journals Effect of Heat Treatment on Microstructure and Impact Toughness of Ti-6Al-4V Manufactured by Selective Laser Melting Process

2017 ◽  
Vol 62 (2) ◽  
pp. 1341-1346 ◽  
Author(s):  
K.-A. Lee ◽  
Y.-K. Kim ◽  
J.-H. Yu ◽  
S.-H. Park ◽  
M.-C. Kim
Keyword(s):  
Heat Treatment ◽  
Impact Toughness ◽  
Selective Laser Melting ◽  
Impact Energy ◽  
Charpy Impact ◽  
Melting Process ◽  
Laser Melting ◽  
Average Impact ◽  
Before And After ◽  
The Impact

AbstractThis study manufactured Ti-6Al-4V alloy using one of the powder bed fusion 3D-printing processes, selective laser melting, and investigated the effect of heat treatment (650°C/3hrs) on microstructure and impact toughness of the material. Initial microstructural observation identified prior-βgrain along the building direction before and after heat treatment. In addition, the material formed a fully martensite structure before heat treatment, and after heat treatment,αandβphase were formed simultaneously. Charpy impact tests were conducted. The average impact energy measured as 6.0 J before heat treatment, and after heat treatment, the average impact energy increased by approximately 20% to 7.3 J. Fracture surface observation after the impact test showed that both alloys had brittle characteristics on macro levels, but showed ductile fracture characteristics and dimples at micro levels.

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.

Effect of N2 Addition on Microstructure and Properties of SAF 2507 Duplex Stainless Steels GTAW Welded Joint

2012 ◽  
Vol 724 ◽  
pp. 127-130
Author(s):  
Dong Fang Du ◽  
Jie Liu ◽  
Guo Ping Li ◽  
Jin Ming Liu
Keyword(s):  
Weld Metal ◽  
Impact Energy ◽  
Welded Joint ◽  
Welding Process ◽  
Welding Parameters ◽  
Shielding Gas ◽  
Micro Hardness ◽  
Weld Metals ◽  
Welding Arc ◽  
The Impact

In this paper, SAF2507 duplex stainless steel (DSS) was welded by GTAW with ER2594 as filler wire, and Ar + N2 as shielding gas. The results show that, with increasing the content of N2 in the shielding gas, the amount of austenite in weld metal increase, the micro-hardness drops and impact energy increases; the use of Ar +2 ~ 3% N2 welding parameters, the microstructure and mechanical properties of welded joints are the best, the austenitic rates and impact energy of weld metals are 51%~53% and 75~88 J, respectively, and the welding process is easy to control; when the content of N2 reach 5%, the impact energy of weld metal decreases obviously and the welding arc is unstable.

Effects of Heat Treatment Process on Microstructure and Mechanical Properties of 31Mn2SiREB Cast Steel

2013 ◽  
Vol 762 ◽  
pp. 418-423
Author(s):  
Feng Zhang Ren ◽  
Feng Jun Li ◽  
Ling Bai ◽  
Yun Fei Wang
Keyword(s):  
Heat Treatment ◽  
Impact Energy ◽  
Treatment Process ◽  
Cast Steel ◽  
Diffusion Annealing ◽  
Heat Treatment Process ◽  
Micro Hardness ◽  
Quenching Temperature ◽  
Pre Treatment ◽  
The Impact

The heat treatment process of 31Mn2SiREB cast steel used in crawler shoes is directly lifted from the heat treatment process of Mn13 high-manganese cast steel, i. e., quenching at 1050 oC after casting. The reasonableness of the process needs to be surveyed. In this paper, the effects of quenching temperature and diffusion annealing pre-treatment on mechanical properties, micro-area composition uniformity and micro-hardness uniformity were investigated. For quenching after casting, the tensile strength and impact energy increase observably with the elevation of quenching temperature, but the impact energy at higher quenching temperature is still very small. The fluctuation of micro-hardness and chemical composition at different micro-areas becomes obviously small with the increase of quenching temperature. For quenching after a diffusion annealing pre-treatment, the impact energy is very high and up to 36.3 J.

Effect of Heat Treatment on Microstructure Evolution and Mechanical Behavior of SKLB3 Alloy

2017 ◽  
Vol 898 ◽  
pp. 380-386
Author(s):  
Wei Yuan ◽  
Dong Mei Liu ◽  
Qiang Song Wang ◽  
Guo Liang Xie
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Impact Energy ◽  
Hot Forging ◽  
Charpy Impact ◽  
Aging Treatment ◽  
Ni Alloy ◽  
Before And After ◽  
Different Temperatures ◽  
The Impact

In this paper, the effect of heat treatment on the microstructure and mechanical properties of hot forging Cu-Ni alloy was studied. Specimens of hot forged Cu-Ni alloy were subjected to first solution treated at 900oC for 2hrs and then aged at different temperatures for 2hrs. The mechanical properties including tensile performance and impact energy, and the microstructure were measured for specimens before and after heat treatment. The results show that both solution and aging treatment have an influence on the grain growth. After heat treatment, the tensile strength decreases very slightly but the yield strength decreases seriously from 235.96MPa to 136.12MPa, while the elongation increases sharply from 36% to 48%. It was also observed that hardness values of the heat-treated alloys are all lower than that of the hot forged alloy. The measurement of Charpy impact energy with V-type notch was performed at 298K and 77K for different specimens. At both temperatures, the impact energies of the specimens are higher than 200J. The microstructure results show that at both temperatures, the alloys are fractured in a ductile mode.

Impact of Heat Treatment on the Structure and Properties of the QE22 Alloy Welded Joints

2012 ◽  
Vol 191 ◽  
pp. 183-188
Author(s):  
Agata Kierzek ◽  
Janusz Adamiec
Keyword(s):  
Heat Treatment ◽  
Welded Joints ◽  
Creep Resistance ◽  
Welded Joint ◽  
Casting Process ◽  
Structure And Properties ◽  
Cast Magnesium Alloy ◽  
The One ◽  
Cast Magnesium ◽  
The Impact

The QE22 cast magnesium alloy containing silver, rare earth elements and zirconium is characterized by high mechanical properties and creep resistance of up to 200 ° C. It is cast gravitationally into sand moulds and permanent moulds. After the casting process any possible defects appearing in the cast are repaired with the application of welding techniques. The repaired cast should possess at least the same properties as the one which does not require any repairs. The aim of this thesis was to determine the impact of the heat treatment on the microstructure of the QE22 alloy welded joint. The creep resistance of the welded joints was also analyzed.

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