scholarly journals Hydrogen-Assisted Cracking in GMA Welding of High-Strength Structural Steel—A New Look into This Issue at Narrow Groove

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 904
Author(s):  
Thomas Schaupp ◽  
Nina Schroeder ◽  
Dirk Schroepfer ◽  
Thomas Kannengiesser
Keyword(s):  
Structural Steel ◽  
Crack Formation ◽  
Gma Welding ◽  
Gas Metal Arc Welding ◽  
High Strength ◽  
Opening Angle ◽  
Diffusible Hydrogen ◽  
Weld Metals ◽  
Metal Arc Welding ◽  
Hydrogen Assisted Cracking

Modern arc processes, such as the modified spray arc (Mod. SA), have been developed for gas metal arc welding of high-strength structural steels with which even narrow weld seams can be welded. High-strength joints are subjected to increasingly stringent requirements in terms of welding processing and the resulting component performance. In the present work, this challenge is to be met by clarifying the influences on hydrogen-assisted cracking (HAC) in a high-strength structural steel S960QL. Adapted samples analogous to the self-restraint TEKKEN test are used and analyzed with respect to crack formation, microstructure, diffusible hydrogen concentration and residual stresses. The variation of the seam opening angle of the test seams is between 30° and 60°. To prevent HAC, the effectiveness of a dehydrogenation heat treatment (DHT) from the welding heat is investigated. As a result, the weld metals produced at reduced weld opening angle show slightly higher hydrogen concentrations on average. In addition, increased micro- as well as macro-crack formation can be observed on these weld metal samples. On all samples without DHT, cracks in the root notch occur due to HAC, which can be prevented by DHT immediately after welding.

scholarly journals Porosity Characteristics and Effect on Tensile Shear Strength of High-Strength Galvanized Steel Sheets after the Gas Metal Arc Welding Process

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1077 ◽  
Author(s):  
Seungmin Shin ◽  
Sehun Rhee
Keyword(s):  
Shear Strength ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
High Strength ◽  
Galvanized Steel ◽  
Tensile Shear Strength ◽  
Tensile Shear ◽  
Tensile Test Specimen ◽  
Metal Arc Welding

In this study, lap joint experiments were conducted using galvanized high-strength steel, SGAFH 590 FB 2.3 mmt, which was applied to automotive chassis components in the gas metal arc welding (GMAW) process. Zinc residues were confirmed using a semi-quantitative energy dispersive X-ray spectroscopy (EDS) analysis of the porosity in the weld. In addition, a tensile shear test was performed to evaluate the weldability. Furthermore, the effect of porosity defects, such as blowholes and pits generated in the weld, on the tensile shear strength was experimentally verified by comparing the porosity at the weld section of the tensile test specimen with that measured through radiographic testing.

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 Hydrogen-assisted cracking in GMA welding of high-strength structural steels using the modified spray arc process

2020 ◽  
Vol 64 (12) ◽  
pp. 1997-2009
Author(s):  
Thomas Schaupp ◽  
Michael Rhode ◽  
Hamza Yahyaoui ◽  
Thomas Kannengiesser
Keyword(s):  
Weld Metal ◽  
Gma Welding ◽  
High Strength ◽  
Economic Benefits ◽  
Structural Steels ◽  
Test Series ◽  
Deposition Rates ◽  
The Past ◽  
Hydrogen Assisted Cracking ◽  
Implant Test

Abstract High-strength structural steels are used in machine, steel, and crane construction with yield strength up to 960 MPa. However, welding of these steels requires profound knowledge of three factors in terms of avoidance of hydrogen-assisted cracking (HAC): the interaction of microstructure, local stress/strain, and local hydrogen concentration. In addition to the three main factors, the used arc process is also important for the performance of the welded joint. In the past, the conventional transitional arc process (Conv. A) was mainly used for welding of high-strength steel grades. In the past decade, the so-called modified spray arc process (Mod. SA) has been increasingly used for welding production. This modified process enables reduced seam opening angles with increased deposition rates compared with the Conv. A. Economic benefits of using this arc type are a reduction of necessary weld beads and required filler material. In the present study, the susceptibility to HAC in the heat-affected zone (HAZ) of the high-strength structural steel S960QL was investigated with the externally loaded implant test. For that purpose, both Conv. A and Mod. SA were used with same heat input at different deposition rates. Both conducted test series showed same embrittlement index “EI” of 0.21 at diffusible hydrogen concentrations of 1.3 to 1.6 ml/100 g of arc weld metal. The fracture occurred in the HAZ or in the weld metal (WM). However, the test series with Mod. SA showed a significant extension of the time to failure of several hours compared with tests carried out with Conv. A.

Effect of DE-GMAW (Double Electroda Gas Metal Arc Welding)’s Resistance on Mechanical and Physical Properties of Aluminium Alloy Weld

2018 ◽  
Vol 789 ◽  
pp. 64-68
Author(s):  
Yustiasih Purwaningrum ◽  
Medilla Kusriyanto ◽  
Rudi Kurniawan ◽  
Okto Akbar Rizky
Keyword(s):  
Physical Properties ◽  
Aluminium Alloy ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Weld Metals ◽  
Metal Arc Welding ◽  
Mechanical And Physical Properties ◽  
Double Electrode ◽  
Gmaw Welding

This paper presented the effect of DE-GMAW (Double electrode gas metal arc welding)resistance on mechanical and physical properties of aluminium alloywelded. DE-GMAWis amethodof welding process that use two electrode. A non consumable torch is added to bypass the current inorder to reduce the heat input. The variation resistance used were 15Ω, 30Ω and 45Ω. Universaltesting machine and Vickers microhardness were used to measured mechanical properties of weldmetals with respect to strength and hardness. The microstructure was investigated by microscopeoptic with 100 x magnification. The grain size of weld metals with resistance value 30Ω is finer than15Ω and 45Ω. Dye penetrant test shows DE-GMAW welding machine that made have goodperformance because it can produce welding joint without surface crack. The results show thatresistance values optimum to DE-GMAW welding on aluminium alloy 5051 with 4 mm thickness is30Ω. It can be seen from the tensile test that shows the highest tensile strength is found in the DEGMAWwelding with resistance values 30Ω.

The First L555 (X80) Pipeline in Japan

2012 ◽  
Author(s):  
Yoshiyuki Matsuhiro ◽  
Noritake Oguchi ◽  
Toshio Kurumura ◽  
Masahiko Hamada ◽  
Nobuaki Takahashi ◽  
...  
Keyword(s):  
Gas Metal Arc Welding ◽  
Control Process ◽  
High Strength ◽  
Longitudinal Direction ◽  
Full Scale ◽  
Ground Movement ◽  
Bending Test ◽  
Metal Arc Welding ◽  
S Curve ◽  
Girth Welds

The construction of the first L555(X80) pipeline in Japan was completed in autumn, 2011.In this paper, the overview of the design consideration of the line, technical points for linepipe material and for girth welds are presented. In recent years the use of high strength linepipe has substantially reduced the cost of pipeline installation for the transportation of natural gas. The grades up to L555(X80) have been used worldwide and higher ones, L690(X100) and L830(X120), e.g., are being studied intensively. In the areas with possible ground movement, the active seismic regions, e.g., pipeline is designed to tolerate the anticipated deformation in longitudinal direction. In Japan, where seismic events including liquefaction are not infrequent, the codes for pipeline are generally for the grades up to L450(X65). Tokyo Gas Co. had extensively investigated technical issues for L555(X80) in the region described above and performed many experiments including full-scale burst test, full-scale bending test, FE analysis on the girth weld, etc., when the company concluded the said grade as applicable and decided project-specific requirements for linepipe material and for girth weld. Sumitomo Metals, in charge of pipe manufacturing, to fulfill these requirements, especially the requirement of round-house type stress-strain (S-S) curve to be maintained after being heated by coating operation, which is critical to avoid the concentration of longitudinal deformation, developed and applied specially designed chemical composition and optimized TMCP (Thermo-Machanical Control Process) and supplied linepipe (24″OD,14.5∼18.9mmWT) with sufficient quality. It had also developed and supplied induction bends needed with the same grade. Girth welds were conducted by Sumitomo Metal Pipeline and Piping, Ltd and mechanized GMAW (Gas Metal Arc Welding) was selected to achieve the special requirements, i.e., the strength of weld metal to completely overmatch the pipe avoiding the concentration of longitudinal strain to the girth weld, and the hardness to be max.300HV10 avoiding HSC (Hydrogen Stress Cracking) on this portion. Both of RT (Radiographic Test) and UT (Ultrasonic Test) were carried out to all the girth welds. These were by JIS (Japan Industrial Standards) and the project-specific requirements.

Effect of Shielding Gas Mixture on Gas Metal Arc Welding (GMAW) of Low Carbon Steel (LR Grade A)

2016 ◽  
Vol 705 ◽  
pp. 250-254 ◽  
Author(s):  
Yustiasih Purwaningrum ◽  
Triyono ◽  
M. Wirawan Pu ◽  
Fandi Alfarizi
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Carbon Steel ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Shielding Gas ◽  
Weld Metals ◽  
Metal Arc Welding

The aimed of this research is to determine the feasibility and effect of the mixture of the shielding gas in the physical and mechanical properties. Low carbon steel LR grade A in a thickness 12 mm were joined in butt joint types using GMAW (Gas Metal Arc Welding) with groove’s gap 5 mm and groove angle’s 400 with variation of shielding gas composition. The composition of shielding gas that used were 100% Ar, 100 % CO2 and 50% Ar + 50 % CO2. The measured of mechanical properties with regard to strength, hardness and toughness using, tensile test, bending test, Vickers hardness Test, and Charpy impact test respectively. The physical properties examined with optical microscope. Results show that tensile strength of welding metals are higher than raw materials. Welds metal with mixing Ar + CO shielding gas has the highest tensile strength. Hardness of weld metals with the shielding gas 100% Ar, 100 % CO2 and 50% Ar + 50 % CO2 are 244.9; 209.4; and 209.4 VHN respectively. The temperature of Charpy test was varied to find the transition temperature of the materials. The temperature that used were –60°C, -40°C, -20°C, 0°C, 20°C , and room temperature. Weld metals with various shielding gas have similar trends of toughness flux that was corellated with the microstructure of weld .

Fracture Mechanics of Conventional and Narrow Groove Pulse Current Gas Metal Arc Welds of HSLA Steel

2012 ◽  
Vol 710 ◽  
pp. 451-456
Author(s):  
Ravi Ranjan Kumar ◽  
P. K. Ghosh
Keyword(s):  
Fracture Toughness ◽  
Weld Metal ◽  
Tensile Properties ◽  
Arc Welding ◽  
Hsla Steel ◽  
Gas Metal Arc Welding ◽  
High Strength ◽  
Compact Tension ◽  
Shielded Metal Arc Welding ◽  
Metal Arc Welding

Mechanical and fracture properties of 20MnMoNi55 grade high strength low alloy (HSLA) steel welds have been studied. The weld joints were made using Gas Tungsten Arc Welding (GTAW), Shielded Metal Arc Welding (SMAW) and Pulse Gas Metal Arc Welding (P-GMAW) methods on conventional V-groove (V-Groove) and Narrow groove (NG-13). The base metal and weld metal were characterised in terms of their metallurgical, mechanical and fracture toughness properties by following ASTM procedures. The J-Integral fracture test was carried out using compact tension C(T) specimen for base and weld metal. The fracture toughness and tensile properties of welds have been correlated with microstructure. In conventional V-groove welds prepared by P-GMAW shows the improvement in initiation fracture toughness (JIC) as compared to the weld prepared by SMAW. Similar improvements in tensile properties have also been observed. This is attributed to reduction in co-axial dendrite content due to lower heat input during P-GMAW process as compared to SMAW. In the narrow groove P-GMA weld prepared at f value of 0.15 has shown relative improvement of JIC as compared to that of the weld prepared by SMAW process.

scholarly journals Pulse spray gas metal arc welding of advanced high strength S650MC automotive steel

10.30544/682 ◽  
2021 ◽  
Vol 27 (4) ◽  
pp. 505-517
Author(s):  
Ashok Kumar Srivastava ◽  
Pradip K Patra
Keyword(s):  
Weld Joint ◽  
Heat Input ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
High Strength Steels ◽  
High Strength ◽  
Filler Wire ◽  
Advanced High Strength Steels ◽  
Metal Arc Welding ◽  
The Impact

With an increasing demand for safer and greener vehicles, mild steel and high strength steel are being replaced by much stronger advanced high strength steels of thinner gauges. However, the welding process of advanced high strength steels is not developed at the same pace. The performance of these welded automotive structural components depends largely on the external and internal quality of weldment. Gas metal arc welding (GMAW) is one of the most common methods used in the automotive industry to join car body parts of dissimilar high strength steels. It is also recognized for its versatility and speed. In this work, after a review of GMAW process and issues in welding of advanced high strength steels, a welding experiment is carried out with varying heat input by using spray and pulse-spray transfer GMAW method with filler wires of three different strength levels. The experiment results, including macro-microstructure, mechanical properties, and microhardness of weld samples, are investigated in detail. Very good weldability of S650MC is demonstrated through the weld joint efficiency > 90%; no crack in bending of weld joints, or fracture of tensile test sample within weld joint or heat affected zone (HAZ), or softening of the HAZ. Pulse spray is superior because of thinner HAZ width and finer microstructure on account of lower heat input. The impact of filler wire strength on weldability is insignificant. However, high strength filler wire (ER100SG) may be chosen as per standard welding practice of matching strength.

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