Microstructure and Toughness of 1000 MPa High Strength Weld Metal

2010 ◽  
Vol 638-642 ◽  
pp. 3441-3446 ◽  
Author(s):  
Wan Sheng Du ◽  
Yun Peng ◽  
Hong Jun Xiao ◽  
Chang Hong He ◽  
Zhi Ling Tian
Keyword(s):  
Electron Microscope ◽  
Weld Metal ◽  
Heat Input ◽  
Welded Joint ◽  
Lath Martensite ◽  
Charpy Impact ◽  
High Strength ◽  
Hardness Test ◽  
Optical Microscope ◽  
Carbon Equivalent

Welding of 1000 MPa high strength alloy steel is difficult because of its welding cold cracking sensitivity and the difficulty in maintaining high joint toughness. In this paper the effects of alloy elements on welding cracking tendency are analyzed, and measures to prevent cold crack are proposed. Welding wires with high strength was deposited into weld metal and welded into joint. Tensile test, micro-hardness test and Charpy impact test were used to evaluate the strength and toughness of weld metal and heat affected zone. Optical microscope, transmission electron microscope and scanning electron microscope were used to analyze the microstructure. It is shown that the weld metal mainly consists of lath martensite, lath bainite, and residual austenite which exists between the laths. The strength of weld metal increases in a small degree with increasing carbon equivalent and its toughness and ductility are not related to carbon equivalent. The toughness and ductility are much sensitive to nonmetallic inclusions. The welded joint has tensile strength of higher than 1000 MPa when welded at heat input of 11 kJ/cm and 15 kJ/cm and the mechanical properties are little influenced by the amount of heat input in this range. The whole welded joint has good comprehensive properties.

Effect of Heat Input on Structure and Mechanical Properties of Low Matched Welded Joint in a 1000MPa Grade Steel

2011 ◽  
Vol 418-420 ◽  
pp. 1184-1187 ◽  
Author(s):  
Zheng Jun Liu ◽  
Chu Ao Wang ◽  
Yun Hai Su ◽  
Fu Dong Zhao ◽  
Le Cheng Li
Keyword(s):  
Mechanical Properties ◽  
Weld Metal ◽  
Heat Input ◽  
Welded Joint ◽  
Optical Microscope ◽  
Metallurgical Structure ◽  
Weld Metal Microstructure ◽  
Optimal Values ◽  
Metal Microstructure ◽  
Grade Steel

In order to investigate the effect of heat input on the microstructure and mechanical properties of low matched high-tensile steel welded joint, the metallurgical structure and mechanical properties of welded joint obtained with different heat input were analyzed using optical microscope , welded joint tensile test and impact test of weld metal. The results show that the optimal values are obtained when the heat input is 11.9KJ/cm,where the tensile strength is 798.45MPa and ballistic work is 69J; Weld metal microstructure is mainly composed by the primary ferrite and acicular ferrite. The width of the dendrite and grain size of the weld metal microstructure increase with the increasing of the heat input.

Mechanical Properties and Microstructure of LR Grade a Thick Plate Welded by Double Side Gas Metal Arc Welding

2016 ◽  
Vol 851 ◽  
pp. 168-172
Author(s):  
Yustiasih Purwaningrum ◽  
Triyono ◽  
Tegar Rileh Argihono ◽  
Ryan Sutrisno
Keyword(s):  
Mechanical Properties ◽  
Gas Flow ◽  
Gas Metal Arc Welding ◽  
Charpy Impact ◽  
Hardness Test ◽  
Charpy Impact Test ◽  
Optical Microscope ◽  
Steel Plates ◽  
Weld Metals ◽  
Metal Arc Welding

Mechanical and microstructure of double side weld with various angle groove was studied in this research. LR Gr A steel plates (12 mm thickness) were welded using GMAW with corresponding 180 A, 23 V, and 20 l/min respectively with current, voltage, and gas flow. Shielding gas and filler metals used are argon and ER 70S-6. The angle groove that used were 20⁰, 40⁰ and 60⁰. The measured of mechanical properties with regard to hardness, toughness and strength using, Vickers hardness test, Charpy impact test and tensile test respectively The microstructure examined with optical microscope. The results show that the highest hardness values found in welds with groove angle 40ͦ. The transition temperatures of weld metals are at temperatures between -20°C to 0°C. Weld metals with all variations of the groove angle has a value of less than 0.1 mmpy. Microstructure of base metals and HAZ were ferrite and pearlite. While the microstructure of weld metals are accicular ferrite, grain boundary ferrite and Widmanstatten ferrite.

scholarly journals Comparative HAZ softening analysis of three different automotive aluminium alloys by physical simulation

2021 ◽  
Vol 66 (1) ◽  
pp. 23-38
Author(s):  
Singh Pratap ◽  
Judit Kovácsb
Keyword(s):  
Aluminium Alloy ◽  
Heat Affected Zone ◽  
Heat Input ◽  
Aluminium Alloys ◽  
Physical Simulation ◽  
Hardness Test ◽  
Optical Microscope ◽  
Automotive Application ◽  
Welding Parameters ◽  
Gleeble 3500

The development of high strength aluminium alloy has revolutionized the automotive industry with innovative manufacturing and technological process to provide high-performance components, weight reduction and also diversified the application field and design consideration for the automotive parts that work under severe conditions, but the selection of proper production parameters is most challenging task to get excellent results. Growing industrial demand of aluminium alloys led to the development of new welding technologies, processes and studies of various parameters effects for its intended purposes. The microstructural changes lead to loss of hardening and thereby mechanical strength in the HAZ welded joint even though the base materials are heat treatable and precipitation hardened. So, our goal is to analyse HAZ softening and analyse the sub-zones as a function of the parameter. In this paper, the influence of weld heat cycle on the heat-affected zone (HAZ) is physically simulated for Tungsten Inert Gas Welding (TIG) using Gleeble 3500 thermomechanical simulator for three different automotive aluminium alloy (AA5754-H22, AA6082-T6 & AA7075-T6) plate of 1 mm thickness. In order to simulate the sub-zones of the heat-affected zone, samples were heated to four different HAZ peak temperatures (550 °C, 440 °C, 380 °C and 280 °C), two linear heat input (100 J/mm and 200 J/mm) by the application of Rykalin 2D model. A series of experiments were performed to understand the behaviour, which make it possible to measure the objective data on the basis of the obtained image of the aluminium alloys tested with heat-affected zone tests in a Gleeble 3500 physical simulator. The main objective is to achieve the weldability of three different automotive aluminium alloys and their comparison based on the welding parameters like heat input. Further, the investigation of HAZ softening and microstructure of the specimens were tested and analysed using Vicker's hardness test and optical microscope respectively. The paper focuses on HAZ softening analysis of different grades of aluminium alloys for automotive application.

CHARACTERISATION OF BIOMEDICAL TITANIUM LAYERS DEPOSITED BY A VACUUM PLASMA SPRAY PROCESS

2021 ◽  
Vol 55 (2) ◽  
pp. 231-235
Author(s):  
Mihailo Mrdak ◽  
Darko Bajić ◽  
Darko Veljić ◽  
Marko Rakin
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Hardness Test ◽  
Optical Microscope ◽  
Mechanical Tests ◽  
Test Method ◽  
Bonding Layer ◽  
Vacuum Plasma Spray ◽  
Porous Ti ◽  
Scanning Electron

In this paper we will describe the process of the deposition of thick layers of VPS-Ti coating, which is used as a bonding layer for the upper porous Ti coatings on implant substrates. In order to deposit the powder, we used HÖGANÄS Ti powder labelled as AMPERIT 154.086 -63 µm. In order to test the mechanical properties and microstructure of the VPS-Ti coating, the powder was deposited on Č.4171 (X15Cr13 EN10027) steel substrates. Mechanical tests of the microhardness of the coating were performed by the Vickers hardness test method (HV0.3) and tensile strength by measuring the force per unit area (MPa). The microhardness of the coating is 159 HV0.3, which is consistent with the microstructure. The coating was found to have a good bond strength of 68 MPa. The morphology of the powder particles was examined on a scanning electron microscope. The microstructure of the coating, both when deposited and etched, was examined with an optical microscope and a scanning electron microscope. By etching the coating layers, it was found that the structure is homogeneous and that it consists of a mixture of low-temperature and high-temperature titanium phases (α-Ti + β-Ti). Our tests have shown that the deposited layers of Ti coating can be used as a bonding layer for porous Ti coatings in the production of implants.

Study on Weldablity of Dissimilar Steel between 16MnR and S31803

2011 ◽  
Vol 391-392 ◽  
pp. 768-772 ◽  
Author(s):  
Li Yang ◽  
Zhan Zhe Zhang
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Impact Toughness ◽  
Weld Metal ◽  
Welded Joint ◽  
Optical Microscope ◽  
Dissimilar Steel ◽  
Austenite Content ◽  
Mechanical Properties And Corrosion ◽  
The Impact

The weldablity of dissimilar steel between 16MnR and S31803 was analyzed and researched. By means of optical microscope (OM), the microstructure of the weld joint was investigated, which is welded by tungsten inert gas arc backing welding (GTAW) and manual arc filling welding (SMAW). The mechanical properties and corrosion resistance of the welded joint was also tested and studied. Results indicate that austenite and acicular ferrite distribute uniformly in the weld metal, which strengths the toughness and ductility of the joint. The austenite content in weld is higher than that in over-heated zone of S31803.The SMAW joint structure is coarsening than that of GTAW and has more austenite content. It is also observed that there are a decarburization layer and a carbon-enriched zone nearby the fusion line. And very small amounts of the third phase of harmful metal phase are found in the fusion zone of S31803 side. The welded joint shows the excellent mechanical properties and corrosion resistance. The impact toughness of the weld metal is higher than in HAZ of 16MnR side, and the impact toughness at GTAW side and in HAZ is superior to the SMAW side.

Effects of Microstructure Transformation on Strengthening and Toughening for Heat-Treated Low Carbon Martensite Stainless Bearing Steel

2015 ◽  
Vol 817 ◽  
pp. 667-674 ◽  
Author(s):  
Xiao Hong Yuan ◽  
Mao Sheng Yang ◽  
Kun Yu Zhao
Keyword(s):  
Electron Microscope ◽  
Cryogenic Treatment ◽  
Lath Martensite ◽  
Optical Microscope ◽  
Bearing Steel ◽  
Strength Increase ◽  
Low Carbon ◽  
Packet Size ◽  
Block Width ◽  
Carbon Martensite

Microstructural transformations and mechanical properties of a low carbon martensite stainless bearing steel treated with different heat treatment parameters and cryogenic treatment (-82°C) were investigated. The function of microstructural transformations on strengthening and toughening process was quantitatively characterized as well. These analyses were performed by the optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and electron back scattering diffraction (EBSD) technique. The obtained results show that with execution of cryogenic treatment and tempering, the tensile strength increase owing to the reduction of retained austenite and fine carbides precipitating respectively. The effect of martensitic microstructure on yield strength increment can be regarded as packet size and block width which conform to Hall-Petch relationship. Meanwhile, the results suggest that the block width is the key structural controlling unit when analyzing the strength-structure relationship of lath martensite in low carbon martensite stainless bearing steel. In addition, packet size can be related to toughness controlling as well because of the same size as cleavage plane.

Weld Metal Hydrogen Cracking in Transmission Pipelines Construction

2010 ◽  
Author(s):  
Sheida Sarrafan ◽  
Farshid Malek Ghaini ◽  
Esmaeel Rahimi
Keyword(s):  
Weld Metal ◽  
Construction Projects ◽  
High Strength Steels ◽  
High Strength ◽  
Carbon Equivalent ◽  
Transverse Cracks ◽  
Diffusible Hydrogen ◽  
Hydrogen Cracking ◽  
Girth Welds ◽  
Welding Position

Developments of high strength steels for natural gas pipelines have been in the forefront of steelmaking and rolling technology in the past decades. However, parallel to such developments in steel industry, the welding technology especially with regards to SMAW process which is still widely used in many projects has not evolved accordingly. Decreasing carbon equivalent has shifted the tendency of hydrogen cracking from the HAZ to the weld metal. Hydrogen cracking due to its complex mechanism is affected by a range of interactive parameters. Experience and data gained from field welding of pipeline construction projects indicated that weld metal hydrogen cracking is related to welding position as it occurs more in the 6 o’clock position of pipeline girth welds. In this research an attempt is made to open up the above observation in order to investigate the contributory factors such as welding position and welding progression in terms of diffusible hydrogen and possibly residual stress considerations. It was observed that transverse cracks produced in laboratory condition may not be detected by radiography. But, the higher tendency for cracking at 6 o’clock position was confirmed through bend test. It is shown that more hydrogen can be absorbed by the weld metal in the overhead position. It is shown that welding progression may also have a significant effect on cracking susceptibility and it is proposed that to be due to the way that weld residual stresses are developed. The observations can have an important impact on planning for welding procedure approval regarding prevention of transverse cracking in pipeline girth welds.

Study on Precipitation Behavior of High Strength Steel Plate Strengthened Complexly by Titanium and Molybdenum

2011 ◽  
Vol 217-218 ◽  
pp. 812-818
Author(s):  
Hong Bin Wang ◽  
Sheng Li Li ◽  
Li Li ◽  
Peng Cheng Ma
Keyword(s):  
Electron Microscope ◽  
Steel Plate ◽  
High Strength ◽  
Optical Microscope ◽  
Steel Plates ◽  
Transmission Electron ◽  
Cold Rolled ◽  
Hot Rolled ◽  
Hot Rolled Steel ◽  
Energy Disperse Spectroscopy

The precipitation behaviors of hot rolling and cold rolled annealing steel plates strengthened complexly by titanium and molybdenum were studied in the paper. The microstructures and precipitate phases were analyzed using optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) with energy disperse spectroscopy (EDS). The results showed that the coarsening square TiN phase and the fine roundness (Ti,Mo)C phase were precipitated mostly in the hot rolled steel plate. As the finishing temperature decreased and coiling holding time increased, the quantity of fine precipitates increased. And also the fine round precipitates increased, dispersion expanded and shape of the phase being uniformed as the annealing temperature increased. Therefore, the strengthen effects can be improved effectively by a reasonable control toward titanium and molybdenum precipitation behaviors.

Welding of High Strength Pipelines

2004 ◽  
Author(s):  
Bill Bruce ◽  
Jose Ramirez ◽  
Matt Johnson ◽  
Robin Gordon
Keyword(s):  
Weld Metal ◽  
Charpy Impact ◽  
High Strength ◽  
Shielding Gas ◽  
Hydrogen Cracking ◽  
Mechanized Welding ◽  
Margin Of Safety ◽  
Girth Welds ◽  
Welding Consumables

This paper presents the results of a project jointly funded by PRCI and EWI to evaluate the welding of X100 pipe grades using commercially available welding consumables. The welding trials included manual, semi-automatic and mechanized welding procedures. It was found that the combination of Pulsed GMAW and ER100S-1 (using a mixed shielding gas) produced both excellent Charpy impact and CTOD performance, but could result in undermatched girth welds if the pipe significantly exceeds minimum strength requirements. Although ER120 S-1 provides an additional margin of safety in strength, which should accommodate variations in X-100 pipe properties, the toughness results were marginal at −10°C. The risk of weld metal hydrogen cracking in X100 girth welds was also investigated.

Compositional Aspects of Cellulosic Electrodes Used for Welding Pipelines

2008 ◽  
Author(s):  
Frank J. Barbaro ◽  
Valerie M. Linton ◽  
Erwin Gamboa ◽  
Leigh Fletcher
Keyword(s):  
Weld Metal ◽  
User Involvement ◽  
Charpy Impact ◽  
Carbon Equivalent ◽  
Welding Parameters ◽  
Line Pipe ◽  
User Input ◽  
Welding Arc ◽  
Simulated Field ◽  
And Performance

The mechanical properties and compositional limits of line pipe for all major pipeline projects are subject to stringent project specific specifications and have substantial user input. The standards for welding electrodes do not have the same level of user involvement and permit significant latitude in terms of alloy design despite the fact that it is known the original electrode design can be markedly altered by elemental transfer as a result of changes in welding parameters and also the condition of the electrodes prior to welding. Several commercially available E8010 consumables have been evaluated under simulated field welding conditions. In addition, the influence of welding arc length and electrode conditioning were investigated. Significant variations in microstructure, hardness and Charpy impact toughness were noted and appear to be primarily related to the final chemical composition of the deposited weld metal. The weld metal carbon equivalent values ranged from 0.20 to 0.42 and all consumables contained additions of Ti and B in the flux coating which resulted in significant levels of B in the final deposited weld metal. It is recommended that the appropriate standards relating to the production and performance of cellulosic consumables be addressed to ensure complete disclosure of consumable formulations to the end user.

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