Targeted influence on the weld strength of high-strength fine-grain structural steels in the GMA welding process through functionalized weld material surfaces

2019 ◽  
Vol 63 (3) ◽  
pp. 783-792 ◽  
Author(s):  
T. Gehling ◽  
K. Treutler ◽  
V. Wesling
Keyword(s):  
Gma Welding ◽  
Welding Process ◽  
High Strength ◽  
Structural Steels ◽  
Weld Strength ◽  
Fine Grain ◽  
Material Surfaces ◽  
Weld Material

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.

Modeling the interrelationship between the parameters for improving weld strength in plastic hot plate welding: A DEMATEL approach

2019 ◽  
Vol 52 (2) ◽  
pp. 117-141
Author(s):  
K Mathiyazhagan ◽  
Krishna Kumar Singh ◽  
V Sivabharathi
Keyword(s):  
Product Design ◽  
Manufacturing Process ◽  
Weight Ratio ◽  
Welding Process ◽  
High Strength ◽  
Weld Strength ◽  
Melting Time ◽  
Hot Plate ◽  
Plate Temperature ◽  
Hot Plate Welding

Application of plastics is increasing day by day since plastics offer many distinct advantages as compared to metals. Plastics has mainly good thermal and electrical insulation properties, corrosion resistance, chemical inertness, and high strength to weight ratio. Additionally, these are cheaper in cost as compared to conventional materials. Plastics are additionally easy to process. Nowadays, product requirements are getting critical and thus product design is getting more complex in shape. To manufacture intricate complex shape creates complexity in manufacturing process which is sometimes very difficult or almost not feasible to produce with single manufacturing process. To manufacture such critical products, welding is a complimentary process. Type of weld joint and welding process can be selected based on the product design and load application on the product. Hot plate welding is very simple welding process as compared to other plastic welding process and most commonly used. Good quality weld is the prime objective of welding process. Weld strength is dependent on several parameters which may be process parameters as well as product parameters. The objective of this study is to identify the key parameters in hot plate welding process of the plastics using Decision Making Trial and Evaluation Laboratory which is one of the prioritization techniques. Results of the study focus on understanding the key parameters affecting the weld strength. Study shows that hot plate temperature, welding time, and melting time are the key parameters affecting the weld strength.

scholarly journals Effect of Coating and Welding Wire Composition on AHSS GMA Welds

2021 ◽  
Vol 100 (12) ◽  
pp. 396-409
Author(s):  
ABDELBASET R. H. MIDAWI ◽  
◽  
ELLIOT BIRO ◽  
SRINATH KISTAMPALLY
Keyword(s):  
Base Material ◽  
Welding Process ◽  
High Strength ◽  
Butt Joint ◽  
Lap Joints ◽  
Weld Strength ◽  
Material Strength ◽  
Filler Materials ◽  
Lap Joint ◽  
Welding Wire

Advanced high-strength steels (AHSS) such as complexphase (CP) and high-formability (HF) steel offer weightsaving advantages for automotive applications such as chassis and frame applications. To prevent material oxidation, materials are often galvanized to protect the substrate from corrosion. However, the weldability of coated AHSS becomes challenging due to the trapping of zinc in the weld molten pool, which could lead to weld defects such as porosity and liquid metal embrittlement cracks. This work focused on the weldability of AHSS (CP800 and 980HF) using the gas metal arc welding process. The roles of both galvanized iron coating and filler material on weld strength were investigated. The welds were performed using two different filler materials: a low-strength filler (ER70S-6) and a high-strength filler (ER100S-6) material. In addition, two different joint configurations were studied: lap joints and butt joints. The results showed that the butt joint had a higher strength compared to the lap joints. Furthermore, the strength of the butt joint overmatched the base material strength in all of the tested materials (both in galvanized and uncoated). In general, lap joint strength undermatched the base material strength, which was attributed to the rotation during tensile testing that induced unaccounted bending stress on the lap joint, while using a higherstrength welding wire improved the tensile strength material in the lap joint configuration. The hardness profiles in the 980HF steel also showed a significant hardness mismatch due to the formation of a fully martensitic microstructure in the heat-affected zone, which led to suppressing the deformation across the lap joint.

Cooling Curve Based Estimation of Mechanical Properties in High Strength Steel Welds

2016 ◽  
Vol 879 ◽  
pp. 1760-1765 ◽  
Author(s):  
Rahul Sharma ◽  
Uwe Reisgen
Keyword(s):  
Mechanical Properties ◽  
Welding Process ◽  
High Strength Steels ◽  
High Strength ◽  
Structural Steels ◽  
Cooling Time ◽  
Cooling Curve ◽  
Welding Parameters ◽  
Steel Welds ◽  
Welding Processes

The application of high strength steels in welded structures relies on easy to use quality assurance concepts for the welding process. For ferritic steels, one of the most common methods for estimating the mechanical properties of welded joints is the cooling time concept t8/5. Even without experimental determination, the calculation of cooling time with previously introduced formulas based on the welding parameters leads to good results. Because high strength structural steels and weld metals with a yield strength of 960 MPa contain higher quantities of alloying elements, the transformation start temperature Ar3 is found to be outside of the range of 800 °C to 500 °C. This leads to inadequate estimation results, as the thermal arrest caused by the microstructural transformation in this case is not considered. In this work the usage of the well-proven cooling time concept t8/5 is analyzed using high strength fine grained structural steels and suitable welding filler wires during gas metal arc and submerged arc welding processes. The results are discussed taking into account the microstructure and the transformation behavior. Based on the experimental work, an improved concept is presented.

scholarly journals The impact of heat input on the mechanical properties and microstructure of High Strength Low Alloy steel welded joint by GMA welding process

2021 ◽  
Vol 9 (3) ◽  
pp. 299-310 ◽  
Author(s):  
Saadat Ali Rizvi ◽  
Rajnish Singh ◽  
Saurabh Kumar Gupta
Keyword(s):  
Mechanical Properties ◽  
Alloy Steel ◽  
Heat Input ◽  
Gma Welding ◽  
Hsla Steel ◽  
Welding Process ◽  
Welding Current ◽  
High Strength ◽  
Low Alloy Steel ◽  
The Impact

The basic aim of this study was to find a relationship between heat input and mechanical properties of high strength low alloy steel (HSLA) welded joints and also elaborate its effect on microstructure. The combined effect of welding current, voltage and speed i.e. Heat Input on mechanical properties of High Strength Low Alloy Steel (ASTM A242 type-II) weldments have been studied in the present work. HSLA steel work pieces were welded by Gas metal arc welding (GMAW) process under varying welding current, arc voltage, and welding speed. Total nine samples were prepared at different heat input level i.e. 1.872 kJ/mm, 1.9333 kJ/mm, 2.0114 kJ/mm, 2.1 kJ/mm, 2.1956 kJ/mm, 2.296 kJ/mm, 2.4 kJ/mm, 2.5067 kJ/mm and 2.6154 kJ/mm It was observed that as heat input increases the ultimate tensile strength and microhardness of weldment decreased while impact strength increased and it was also observed that on increasing the heat input grain size of microstructure tends to coarsening it is only due to decreasing in cooling rate.

Effect of Shot-Peening on Fine Grain Steel

2007 ◽  
Vol 561-565 ◽  
pp. 2103-2106
Author(s):  
Katsuhiro Seki ◽  
Hashimoto Munetoh ◽  
Masahide Gotoh ◽  
Hajime Hirose
Keyword(s):  
Shot Peening ◽  
Welding Process ◽  
High Strength ◽  
Negative Influence ◽  
Residual Tensile Stress ◽  
Stress Distributions ◽  
Structural Components ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fine Grain

Recently, the study of fine grain steels aimed at achieving into high strength has become active. Welding is one of the most effective methods for connecting the structural components. For those cases, the negative influence of any residual tensile stress induced during the welding process must be considered. It has been proved that shot-peening can effectively solve this problem. However, the influence of the Shot-Peening process on fine grain steels after welding has only been briefly reported up to now. In this study, fine grain steels were used, and specimens were obtained after heat treatment. Residual stress distributions near the surface of the fine grain steel after shot-peening were measured by X-ray diffraction technology. Moreover, the effect of hardness on distributions near the shot-peened surface was also estimated.

scholarly journals Weldability of micro-alloyed high-strength pipeline steels using a new friction welding variant

2010 ◽  
Vol 1 (1) ◽  
pp. 94-101
Author(s):  
Koen Faes ◽  
Patrick De Baets ◽  
Alfred Dhooge ◽  
Wim De Waele ◽  
Rudi Denys ◽  
...  
Keyword(s):  
Impact Toughness ◽  
Heat Input ◽  
Friction Welding ◽  
Pipeline Steel ◽  
Welding Process ◽  
High Strength ◽  
Weld Strength ◽  
Welding Method ◽  
Fully Automatic ◽  
Welding Procedure

An innovative welding method for fully automatic joining of pipelines has been developed. Theproposed welding procedure is a variant of the conventional friction welding process. A rotatingintermediate ring is used to generate heat necessary to realise the weld. The working principles of thewelding process are described. The weldability of the micro-alloyed high-strength pipeline steel API-5L X65is experimentally investigated. It was found that the new welding process is suitable for joining this material.When welding with a sufficiently low heat input, a high weld quality is obtained. Under these circumstancesthe weld strength, ductility and impact toughness are high and fulfil the requirements of the commonly usedstandard EN 12732 for joining pipes.

Effects of bottom plate in friction stir welding of AA6061-T6

2020 ◽  
Vol 118 (1) ◽  
pp. 108
Author(s):  
M.A. Vinayagamoorthi ◽  
M. Prince ◽  
S. Balasubramanian
Keyword(s):  
Mechanical Properties ◽  
Axial Load ◽  
Weld Zone ◽  
Welding Process ◽  
Bottom Plate ◽  
Welding Parameters ◽  
Nugget Zone ◽  
Friction Stir ◽  
Weld Joints ◽  
Fine Grain

The effects of 40 mm width bottom plates on the microstructural modifications and the mechanical properties of a 6 mm thick FSW AA6061-T6 joint have been investigated. The bottom plates are placed partially at the weld zone to absorb and dissipate heat during the welding process. An axial load of 5 to 7 kN, a rotational speed of 500 rpm, and a welding speed of 50 mm/min are employed as welding parameters. The size of the nugget zone (NZ) and heat-affected zone (HAZ) in the weld joints obtained from AISI 1040 steel bottom plate is more significant than that of weld joints obtained using copper bottom plate due to lower thermal conductivity of steel. Also, the weld joints obtained using copper bottom plate have fine grain microstructure due to the dynamic recrystallization. The friction stir welded joints obtained with copper bottom plate have exhibited higher ductility of 8.9% and higher tensile strength of 172 MPa as compared to the joints obtained using a steel bottom plate.

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