scholarly journals Experimental review of thermal analysis of dissimilar welds of High-Strength Steel

2019 ◽  
Vol 58 (1) ◽  
pp. 38-49 ◽  
Author(s):  
Francois Njock Bayock ◽  
Paul Kah ◽  
Belinga Mvola ◽  
Pavel Layus
Keyword(s):  
Heat Treatment ◽  
Thermal Analysis ◽  
Heat Input ◽  
Power Plants ◽  
Welding Process ◽  
Postweld Heat Treatment ◽  
High Strength ◽  
Dissimilar Welding ◽  
Dissimilar Welds ◽  
Wide Range

Abstract Dissimilar welding offers exiting benefits for a wide range of engineering applications, such as automotive bodies, piping systems of nuclear power plants, health equipment. The main advantages of dissimilarwelding applications areweight reductions, lower costs, unique properties combinations, and improved energy-efficiency. The properties of dissimilar weld depend on the type of welding process used, the accuracy of the process parameters control, the characteristics of the base metal and the heat treatment procedures. The current study reviews the scientific literature on the topic of thermal analysis of dissimilar high-strength steels (HSS) welding. The review of experimental data was carried out to analyze the variable heat input effect on dissimilar welds. The results indicate the welds mechanical properties irregularity and reduction in toughness and tensile strength due to uneven changes in the microstructure. Furthermore, postweld heat treatment (PWHT) often resulted in the formation of intermetallic compounds whose properties are dependent on the duration of treatment. The research results can be used to optimize the heat input of the HSS welding process.

Cold Metal Transfer Spot Joining of AA6061-T6 to Galvanized DP590 Under Different Modes

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
HaiYang Lei ◽  
YongBing Li ◽  
Blair E. Carlson ◽  
ZhongQin Lin
Keyword(s):  
Heat Input ◽  
Mechanical Performance ◽  
Welding Process ◽  
High Strength ◽  
Metal Transfer ◽  
Cold Metal Transfer ◽  
Spot Joining ◽  
Predrilled Hole ◽  
Joint Quality ◽  
Cold Metal

In order to meet the upcoming regulations on greenhouse gas emissions, aluminum use in the automotive industry is increasing. However, this increase is now seen as part of a multimaterial strategy. Consequently, dissimilar material joints are a reality, which poses significant challenges to conventional fusion joining processes. To address this issue, cold metal transfer (CMT) spot welding process was developed in the current study to join aluminum alloy AA6061-T6 as the top sheet to hot dip galvanized (HDG) advanced high strength steel (AHSS) DP590 as the bottom sheet. Three different welding modes, i.e., direct welding (DW) mode, plug welding (PW) mode, and edge plug welding (EPW) mode were proposed and investigated. The DW mode, having no predrilled hole in the aluminum top sheet, required concentrated heat input to melt through the Al top sheet and resulted in a severe tearing fracture, shrinkage voids, and uneven intermetallic compounds (IMC) layer along the faying surface, leading to poor joint properties. Welding with the predrilled hole, PW mode, required significantly less heat input and led to greatly reduced, albeit uneven, IMC layer thickness. However, it was found that the EPW mode could homogenize the welding heat input into the hole and thus produce the most stable welding process and best joint quality. This led to joints having an excellent joint morphology characterized by the thinnest IMC layer and consequently, best mechanical performance among the three modes.

scholarly journals Development of Welding P92 Pipes Using the Reduced Pressure Electron Beam Welding Process for a Study of Creep Performance

2014 ◽  
Author(s):  
Nick Bagshaw ◽  
Chris Punshon ◽  
John Rothwell
Keyword(s):  
Electron Beam ◽  
Heat Input ◽  
Power Plants ◽  
Electron Beam Welding ◽  
Welding Process ◽  
Welding Parameters ◽  
Pipe Material ◽  
Reduced Pressure ◽  
Type Iv ◽  
Type Iv Cracking

Boiler and steam piping components in power plants are fabricated using creep strength enhanced ferritic (CSEF) steels, which often operate at temperatures above 550°C. Modification of alloy content within these steels has produced better creep performance and higher operating temperatures, which increases the process efficiency of power plants. The improved materials, however, are susceptible to type IV cracking at the welded regions. A better understanding of type IV cracking in these materials is required and is the basis of the Technology Strategy Board (TSB) UK funded VALID (Verified Approaches to Life Management & Improved Design of High Temperature Steels for Advanced Steam Plants) project. In order to study the relationship between creep performance and heat input during welding, several welds with varying amounts of heat input and resultant HAZ widths were produced using the electron beam welding process. The welding parameters were developed with the aid of weld process modeling using the finite element (FE) method, in which the welding parameters were optimized to produce low, medium and high heat input welds. In this paper, the modeling approach and the development of electron beam welds in ASTM A387 grade P92 pipe material are presented. Creep specimens were extracted from the welded pipes and testing is ongoing. The authors acknowledge the VALID project partners, contributors and funding body: Air Liquide, Metrode, Polysoude, E.ON New Build & Technology Ltd, UKE.ON, Doosan, Centrica Energy, SSE, Tenaris, TU Chemnitz, The University of Nottingham, The Open University and UK TSB. Paper published with permission.

RAFFMETAL EN AB-Al Si7Mg0.3 (EN AB-42100)

Alloy Digest ◽  
2021 ◽  
Vol 70 (9) ◽  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Corrosion Resistance ◽  
High Strength ◽  
Heat Treating ◽  
Magnesium Content ◽  
Casting Alloy ◽  
Permanent Mold ◽  
Good Corrosion Resistance ◽  
Wide Range

Abstract Raffmetal EN AB-Al Si7Mg0.3 (EN AB-42100) is a heat-treatable, Al-Si-Mg casting alloy in ingot form for remelting. It is used extensively for producing sand, permanent mold and investment castings for applications requiring a combination of excellent casting characteristics, high strength with good elongation, and good corrosion resistance. This alloy can be produced to a wide range of mechanical properties by making small adjustments to the magnesium content and/or heat treatment. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-480. Producer or source: Raffmetal S.p.A.

Cause Analysis and Preventive Measures against Cracks in 15Cr1Mo1V Steel Welded Joint in Service

2017 ◽  
Vol 863 ◽  
pp. 328-333
Author(s):  
Wei Shi ◽  
Yi Shi Lv ◽  
Zhong Bing Chen ◽  
Ling Hui Meng ◽  
Li Jun Zhang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Stress Concentration ◽  
Welded Joint ◽  
Welding Process ◽  
Postweld Heat Treatment ◽  
Additional Stress ◽  
Heat Affect Zone ◽  
Crack Morphology ◽  
Deformation Ability ◽  
Postweld Heat

Characteristics and forming causes of the cracks in welded joint of 15Cr1Mo1V steel serviced 70000h are investigated by mechanical and chemical testing and crack morphology observation. Results show that the cracks initiate from welded metal or coarse grain heat affect zone (CGHAZ) near fusion line, and there are three kinds of defects observed in the crack region, which are macrocracks, microcracks and voids. According to the forming position, process and morphology of the cracks, it is estimated that the cracks are a kind of stress relief crack (SRC). The main reasons of the cracking are because of residual stress caused by improper temperature field during post welding heat treatment, strong stress concentration caused by welding structure, additional stress caused by abnormal hangers & supports and decreased ductility of welded joint in service. The SRC in welded joint can be avoided through optimizing the welding process and postweld heat treatment(PWHT) process to ensure enough critical ductility deformation ability εc and avoiding and reducing stress concentration and additional stress to decrease ductility deformation εP of welded joint which make εc>εp consistently.

Effect of the FCAW Welding Process and Post Weld Heat Treatment on the Properties and Microstructure of the Weld Joints of Heat Treated 4330V Steel

2015 ◽  
Vol 809-810 ◽  
pp. 437-442
Author(s):  
Jacek Górka ◽  
Michał Miłoszewski
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Weld Metal ◽  
Heat Input ◽  
Large Diameter ◽  
Welding Process ◽  
Post Weld Heat Treatment ◽  
High Toughness ◽  
Interpass Temperature ◽  
Weld Heat

4330V is a high strength, high toughness, heat treatable low alloy steel for application in the oil, gas and aerospace industries. It is typically used for large diameter drilling parts where high toughness and strength are required. The research describes the effect of preheat temperature, interpass temperature, heat input, and post weld heat treatment on strength, hardness, toughness, and changes to microstructure in the weld joint. Welding with the lower heat input and no post weld heat treatment resulted in optimal mechanical properties in the weld metal. Austempering at 400 °C resulted in optimal mechanical properties in the HAZ. Increasing preheat and interpass temperature from 340 °C to 420 °C did not improve Charpy V-notch values or ultimate tensile strength in the weld metal or heat affected zones. The higher temperature increased the width of the heat affected zone. Austempering at 400 °C reduced HAZ hardness to a level comparable to the base metal. Both tempering and austempering at 400 °C for 10 hours reduced toughness in the weld metal.

Finite Element Analysis of Effects of Preheating and Postweld Heat Treatment on Residual Stress in Pipe Welding

2011 ◽  
Vol 314-316 ◽  
pp. 428-431 ◽  
Author(s):  
Hui Du ◽  
Dong Po Wang ◽  
Chun Xiu Liu ◽  
Hai Zhang
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Welding Process ◽  
Postweld Heat Treatment ◽  
Element Model ◽  
Element Analysis ◽  
Pipe Welding ◽  
Postweld Heat

To simulate preheating and postweld heat treatment of Q345 steel pipe welding, the finite element model was established. The welding process was simulated by method of the ANSYS element birth and death technique. In this paper, to obtain the distribution of the temperature field and stress field in different situations, preheating processes with two different values of temperature and postweld heat treatment process were simulated respectively. The results show that preheating can homogenize residual stress distribution of the weldment and decrease the residual stress. The heat treatment reduces the residual stress in inner and outer walls by 24% and 70% respectively and the stress distribution is more even and stress concentration is reduced.

A Study of Temper Bead Technique on A508 Steel Welds

2011 ◽  
Vol 295-297 ◽  
pp. 1938-1942
Author(s):  
Wei Chih Chung ◽  
Leu Wen Tsay ◽  
Chun Chen
Keyword(s):  
Heat Treatment ◽  
Heat Affected Zone ◽  
Filler Metal ◽  
Welding Process ◽  
Postweld Heat Treatment ◽  
Weld Interface ◽  
Structural Components ◽  
Time Saving ◽  
Steel Welds ◽  
Postweld Heat

The use of temper bead technique in an attempt to eliminate the conventional postweld heat treatment (PWHT) in welding of A508 steel with Alloy 52 filler metal was evaluated. A PWHT at 621°C for 24 h reduced hardness in the heat-affected zone (HAZ) of the conventional welds but led to forming a carbon-denuded zone near the weld interface. The temper bead welding process not only softened the hardness in the HAZ but also diminished the carbon-denuded zone of A508-Alloy 52 welds. Apparently, the temper bead technique provides a convenient and time- saving process for welding/repairing large structural components.

Influence of heat input and solubilizing heat treatment on the impact properties of SAW joints in SAF 2205 duplex steel

2012 ◽  
Vol 1381 ◽  
Author(s):  
M. Merlin ◽  
R. Vazquez-Aguilar ◽  
C. Soffritti ◽  
A. Reyes-Valdes
Keyword(s):  
Heat Treatment ◽  
Heat Input ◽  
Welding Process ◽  
Optical Microscope ◽  
Image Analyzer ◽  
Secondary Phases ◽  
Impact Properties ◽  
Steel Joints ◽  
Saf 2205 ◽  
The Impact

ABSTRACTIn this study the influence of heat input (HI) and heat treatment on submerged arc welded duplex SAF 2205 steel joints has been evaluated. In particular, multi-pass welding operations have been performed on 18 mm thick plates using four different heat inputs; a post-weld solubilizing heat treatment has been carried out in order to reduce the microstructural effects on the structure of the heat affected zone (HAZ). Instrumented impact strength tests have been performed on Charpy samples machined from the welded joints; the total absorbed energy and the two complementary contributions of initiation and propagation energies have been evaluated and correlated to the percentages of ferrite and austenite. The microstructures and the fracture profiles have been observed using an optical microscope (OM) and quantitatively analyzed by means of an image analyzer. A scanning electron microscope (SEM) equipped by energy dispersive X-ray spectroscopy (EDS) has been used to study the fractured surfaces. Hardness profiles have been performed across the joints in order to verify the hardness variations. A total absence of secondary phases has been found on the joints due to the performing of a suitable solubilizing heat treatment after the welding process. The results have shown that the impact properties of the samples have been mostly affected by the different heat inputs; in some cases a partial welding penetration has been found.

Weld Hardness Study of P91 Welded Pipes with Post Weld Heat Treatment for Elevated Temperature Application in Power Plants

2015 ◽  
Vol 1115 ◽  
pp. 503-508 ◽  
Author(s):  
Muhammad Sarwar ◽  
Mohd Amin bin Abd Majid
Keyword(s):  
Heat Treatment ◽  
Power Plant ◽  
Weld Metal ◽  
Creep Strength ◽  
Power Plants ◽  
Thermal Power ◽  
Base Material ◽  
Welding Process ◽  
Post Weld Heat Treatment ◽  
Weld Heat

The creep strength-enhanced ferritic (CSEF) steels are undergoing an encouraged use around the world especially in power plant construction. On construction sites, it has always been the target to have no problems in welded joints but premature failures are being encountered. The primary reason of these premature failures is found to be the improper heat treatment that is mandatorily carried out to achieve the required weld hardness. Weld hardness has close relationship with creep strength and ductility of the welded structures. Hence it is important for any weld to achieve certain level of weld hardness. This study aims at ascertaining the importance of Post Welding Heat Treatment (PWHT) in achieving the required hardness in creep-strength enhanced ferritic (CSEF) materials.The study was carried out on the welding of alloy steel ASTM A335 Gr. P-91 with the same base material (ASTM A335 Gr. P-91) by Gas Tungsten Arc Welding (GTAW) process using ER90S-B9 filler wire with pre-heat of 200oC (min) and inter-pass temperature of 300oC (max). After welding, the joints were tested for soundness with Radiography testing. Induction heating was used for heat treatment of P91 pipes during welding and post weld heat treatment. The effect of Post Weld Heat Treatment (PWHT) was investigated on the Weld metal and the Heat Affected Zones (HAZ) by hardness testing. It is perceived that the scattered and higher hardness values, more than 250HB in 2” P91 pipes in the weld metal and in the heat affected zones, can be brought into the lower required level, less than 250HB, with an effective post weld heat treatment at 760°C for 2hrs.It is concluded that PWHT is the most effective way of relieving the welding stresses that are produced due to high heat input in the welding process and to achieve the required level of hardness in the weld as well as in the heat affected zones (HAZ) in thermal power plant main steam piping.

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