Effect of Transformation Temperature of Weld Metal on Welding Distortion

2008 ◽  
Author(s):  
Yasushi Morikage ◽  
Takahiro Kubo ◽  
Koichi Yasuda ◽  
Yoshiki Mikami ◽  
Masahito Mochizuki ◽  
...  
Keyword(s):  
Weld Metal ◽  
Welded Joints ◽  
Transformation Temperature ◽  
Welded Joint ◽  
Steel Structures ◽  
Angular Distortion ◽  
Welding Distortion ◽  
Uniform Heating ◽  
Welding Wire ◽  
Heating And Cooling

Welding distortion during welding is an inevitable outcome of weld metal shrinkage due to non-uniform heating and cooling in welded joints. Several studies have investigated methods of estimating and controlling welding distortion in order to construct steel structures correctly, easily and efficiently. In the present study, the effect of transformation expansion of the weld metal on welding distortion was investigated in order to develop a welding wire that reduces welding distortion. Concretely, experiments and numerical simulations were performed on the effect of the transformation temperature of the weld metal on angular distortion of a horizontal fillet welded joint. The results showed that angular distortion of the welded joint decreases when the martensitic transformation start temperature of the weld metal decreases in the range from 350°C to 450°C. Based on this result, a welding wire that is effective in reducing welding angular distortion was developed considering usability, weldability and the mechanical properties of welded joints.

scholarly journals Investigation of the Residual Stress in a Multi-Pass T-Welded Joint Using Low Transformation Temperature Welding Wire

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 325
Author(s):  
Zhongyuan Feng ◽  
Ninshu Ma ◽  
Seiichiro Tsutsumi ◽  
Fenggui Lu
Keyword(s):  
Residual Stress ◽  
Welded Joints ◽  
Transformation Temperature ◽  
Compressive Residual Stress ◽  
Welded Joint ◽  
Numerical Study ◽  
Weld Zone ◽  
Welding Wire ◽  
Finish Temperature ◽  
Welding Materials

We investigated whether low transformation temperature (LTT) welding materials are beneficial to the generation of compressive residual stress around a weld zone, thus enhancing the fatigue performance of the welded joint. An experimental and numerical study were conducted in order to analyze the residual stress in multi-pass T-welded joints using LTT welding wire. It was found that, compared to the conventional welded joint, greater tensile residual stress was induced in the flange plate of the LTT welded joints. This was attributed to the reheat temperature of the LTT weld pass during the multi-pass welding. The formerly-formed LTT weld pass with a reheat temperature lower than the austenite finish temperature converted the compressive residual stress into tensile stress. The compressive residual stress was generated in the regions with a reheat temperature higher than the austenite finish temperature, indicating that LTT welding materials are more suitable for single-pass welding.

Microstructures and Mechanical Properties of Welded Joints of Several High Tensile Strength Steel

2018 ◽  
Vol 941 ◽  
pp. 224-229
Author(s):  
Takahiro Izumi ◽  
Tatsuya Kobayashi ◽  
Ikuo Shohji ◽  
Hiroaki Miyanaga
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Weld Metal ◽  
Welded Joints ◽  
Welded Joint ◽  
Steel Plates ◽  
Fatigue Properties ◽  
High Tensile Strength ◽  
The Matrix ◽  
Microstructures And Mechanical Properties

Microstructures and mechanical properties of lap fillet welded joints of several high and ultra-high tensile strength steel by arc welding were investigated. Steel plates having tensile strength of 400 (SPH400W), 590 (SPC590Y, SPC590R), 980 (SPC980Y) and 1500 MPa (SAC1500HP) class with 2 mm thickness were prepared. Four types of joints were formed by MAG welding; SPH400W/SPH400W, SPC590Y/SPC590Y, SPC980Y/SPC980Y and SAC1500HP/SPC590R. In joints with SPC590Y, SPC980Y and SAC1500HP steel which matrixes are martensitic microstructures, the HAZ softens due to transformation of martensite into ferrite with precipitating cementite. By using high and ultra-high tensile strength steel, the weld metal is strengthened due to dilution of the matrix into the weld metal and thus tensile shear strength of the welded joint increases. In the fatigue test, similar S-N diagrams were obtained in the all welded joints investigated. It seems that the effect of stress concentration due to the shape of the welded joint on fatigue properties is larger than that of the strength of the matrix.

scholarly journals Application of Dynamic Beam Positioning for Creating Specified Structures and Properties of Welded Joints in Electron-Beam Welding

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2233
Author(s):  
Tatyana Olshanskaya ◽  
Vladimir Belenkiy ◽  
Elena Fedoseeva ◽  
Elena Koleva ◽  
Dmitriy Trushnikov
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Weld Metal ◽  
Thermal Effect ◽  
Welded Joints ◽  
Electron Beam Welding ◽  
Welded Joint ◽  
Parent Metal ◽  
Cooling Rates ◽  
Structures And Properties

The application of electron beam sweep makes it possible to carry out multifocal and multi-beam welding, as well as combine the welding process with local heating or subsequent heat treatment, which is important when preparing products from thermally-hardened materials. This paper presents a method of electron beam welding (EBW) with dynamic beam positioning and its experimental-calculation results regarding the formation of structures and properties of heat-resistant steel welded joints (grade of steel 20Cr3MoWV). The application of electron beam oscillations in welding makes it possible to change the shape and dimensions of welding pool. It also affects the crystallization and formation of a primary structure. It has been established that EBW with dynamic beam positioning increases the weld metal residence time and the thermal effect zone above the critical A3 point, increases cooling time and considerably reduces instantaneous cooling rates as compared to welding without beam sweep. Also, the difference between cooling rates in the depth of a welded joint considerably reduces the degree of structural non-uniformity. A bainitic–martensitic structure is formed in the weld metal and the thermal effect zone throughout the whole depth of fusion. As a result of this structure, the level of mechanical properties of a welded joint produced from EBW with dynamic electron beam positioning approaches that of parent metal to a greater extent than in the case of welding by a static beam. As a consequence, welding of heat-resistant steels reduces the degree of non-uniformity of mechanical properties in the depth of welded joints, as well as decreases the level of hardening of a welded joint in relation to parent metal.

Creep Strength Evaluation of a New and a Used Grade 91 Welded Joints by Using a Miniature Specimen

2018 ◽  
Author(s):  
Takashi Ogata
Keyword(s):  
Weld Metal ◽  
Strain Rate ◽  
Creep Strain ◽  
Base Metal ◽  
Welded Joints ◽  
Welded Joint ◽  
Creep Damage ◽  
Creep Strain Rate ◽  
Standard Size ◽  
Grade 91

Grade 91 is widely used for steam pipes and tubes in high temperature boilers of ultra-super critical power plants in Japan. It was reported that creep damage may initiate at the fine grain region within the heat affected zone (HAZ) in welded joints prior to the base metal, so called “Type IV” damage, which causes steam leakage in existing power plants. Therefore, development of creep damage assessment methods is not only an important but also an urgent subject to maintain operation reliability. In order to evaluate creep damage of welded joints based on finite element analyses, creep deformation properties of a base metal, a weld metal and a HAZ have to be obtained from creep tests. However, it is difficult to cut a standard size creep specimen from the HAZ region. Only a miniature size specimen is available from the narrow HAZ region. Therefore, development of creep testing and evaluation technique for miniature size specimens is highly expected. In this study, a miniature tensile type solid bar specimen with 1mm diameter was machined from a base metal, a weld metal and a HAZ of a new and a used Grade 91 welded joints, and creep tests of these miniature specimens were conducted by using a special developed creep testing machine. It was found that creep deformation property is almost identical between the base metal and weld metal, and creep strain rate of the HAZ is much faster than that of these metals in the new welded joint. Relationships between stress and creep strain rates of the base metal and the HAZ in the used welded joint are within scatter bands of those in the new material. On the other hand, creep strain rate of the weld metal in the used welded joint became much faster than that in the new one. Then both the standard size and the miniature size cross weld specimens were machined from the new and the used welded joints and were tested under the same temperature and stress conditions. Rupture time of the miniature cross weld specimen is much shorter than that of the standard size cross weld specimen. The finite element creep analysis of the specimens indicates that higher triaxiality stress yields within the HAZ of the standard size specimen than that of the miniature specimen causing faster creep strain rate in the HAZ of the miniature cross weld specimen.

Influence of Hydrogen on Microstructure of Electron Beam Welded Joint

2013 ◽  
Vol 753-755 ◽  
pp. 367-371
Author(s):  
Xin Liu ◽  
Zhi Yong Mao
Keyword(s):  
Titanium Alloy ◽  
Electron Beam ◽  
Weld Metal ◽  
Hydrogen Content ◽  
Welded Joints ◽  
Welded Joint ◽  
Optical Microscope ◽  
Hydrogen Charging ◽  
Tc4 Titanium Alloy ◽  
Oxygen Analyzer

Hydrogen distributions of TC4 electron beam welded joints with different hydrogen contents were measured by hydrogen oxygen analyzer. Microstructures of electron beam welded joints for TC4 titanium alloy with different hydrogen contents were observed and analyzed by optical microscope and TEM. And the influence of hydrogen on microstructure of the joints was investigated. The results show that the hydrogen content of weld HAZ is higher than other zones in the electron beam welded joints, while the hydrogen content of fusion zone is lower than other zones in the electron beam welded joints. The microstructure of the weld metal is fine lamellar α + β phase after hydrogen charging. In the range of hydrogen contents discussed in this study (from 0 to 0.101 wt. %), with the increase of hydrogen content, there is little change in the appearance of the microstructure of the weld metal. There are stacking fault and dislocation in the microstructure of TC4 electron beam welded joints with different hydrogen contents after hydrogen charging. The presence of hydrogen can promote the formation of twins in electron beam welded joints. With the increase of hydrogen content, the number of twins is increased.

Effect of Hydrogen on Microstructure of TA15 Electron Beam Welded Joint

2011 ◽  
Vol 287-290 ◽  
pp. 2393-2396 ◽  
Author(s):  
Xin Liu ◽  
Zhi Yong Mao ◽  
Yong Ping Lei
Keyword(s):  
Titanium Alloy ◽  
Electron Beam ◽  
Weld Metal ◽  
Hydrogen Content ◽  
Welded Joints ◽  
Welded Joint ◽  
Hydrogen Charging ◽  
Β Phase ◽  
Ta15 Titanium Alloy ◽  
Certainty Level

Microstructures of electron beam welded joints for TA15 titanium alloy with different hydrogen contents were observed and analyzed by SEM and TEM. And the influence of hydrogen on microstructure of the joints was investigated. The results show that the microstructure of the weld metal is lamellar α+β phase after hydrogen charging. In the range of hydrogen contents discussed in this study (from 0 to 0.101 wt%), With the increase of hydrogen content, there is little change in the appearance of the microstructure of the weld metal. The presence of hydrogen can promote the growth of twins in electron beam welded joints. With the increase of hydrogen content, the number of twins is increased. When hydrogen content reaches to a certainty level, hydrides are found in TA15 electron beam welded joints.

The Influence of Pulsed Heat and Power Supply on the Structure and Properties of Welded Joint Metals and Surfaced Coatings

2015 ◽  
Vol 788 ◽  
pp. 259-266
Author(s):  
Yuriy N. Saraev ◽  
Valeriy P. Bezborodov ◽  
Evgenya A. Putilova
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Weld Metal ◽  
Power Supply ◽  
Welded Joints ◽  
Arc Welding ◽  
Structural Changes ◽  
Welded Joint ◽  
Structure And Properties ◽  
Pulsed Mode

We have investigated the influence of the modes of adaptive pulse-arc welding and surfacing on the structure and physical-mechanical properties of welded joints of steel 09Mn2Si and the surfaced composition of this steel coated with a modified powder material of chromium carbide with the submicrocrystalline structure. It is shown that the pulsed mode of welding and surfacing can improve the homogeneity of the structure of the welded joint of steel and a surfaced coating and reduce the grain size of metals in both of them. Structural changes lead to an increase in ductility and toughness of the weld metal.

Structure of welded joints of 15Kh2MFA steel completed with low carbon surfacing without heat treatmen

2020 ◽  
pp. 35-43
Author(s):  
M. N. Timofeev ◽  
S. N. Galyatkin ◽  
R. I. Samoylenko ◽  
Yu. M. Markova
Keyword(s):  
Heat Treatment ◽  
Base Metal ◽  
Welded Joints ◽  
Welded Joint ◽  
Chemical Elements ◽  
Steel Structures ◽  
Low Carbon ◽  
15Kh2mfa Steel

The paper studies the 15Kh2MFA steel structures at various sections of the welded joint performed without heat treatment after welding with low-carbon surfacing. It is shown that there are three zones in lowcarbon surfacing, which differ in the content of chemical elements passing from the base metal to the deposited one, as well as in the tendency to form hardened structures during welding.

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