Welding Properties and Fatigue Resistance of S690QL High Strength Steels

2015 ◽  
Vol 812 ◽  
pp. 29-34 ◽  
Author(s):  
Ádám Dobosy ◽  
János Lukács
Keyword(s):  
Fatigue Resistance ◽  
Welded Joints ◽  
Gas Metal Arc Welding ◽  
Research Work ◽  
Base Material ◽  
High Strength Steels ◽  
High Strength ◽  
Fatigue Tests ◽  
Metal Arc Welding ◽  
Welding Properties

The objective of this article is to present the first results of our research work. In order to determination and comparison of the fatigue resistance, high cycle fatigue tests (HCF) were performed on RUUKKI OPTIM S690QL quenched and tempered high strength steel. In parallel these; welded joints were made on the same steel using gas metal arc welding (GMAW, MIG/MAG) to preparation of the cyclic investigations of the welded joints. In the article, the performance of the welding experiments will be presented; along with the results of the HCF tests executed on the base material and its welded joints. Furthermore, our results will be compared with different literary data.

The Effect of the Filler Material Choice on the High Cycle Fatigue Resistance of High Strength Steel Welded Joints

2017 ◽  
Vol 885 ◽  
pp. 111-116 ◽  
Author(s):  
Ádám Dobosy ◽  
János Lukács
Keyword(s):  
Fatigue Resistance ◽  
Welded Joints ◽  
High Cycle Fatigue ◽  
Material Selection ◽  
Gas Metal Arc Welding ◽  
Research Work ◽  
Base Material ◽  
High Strength ◽  
Filler Material ◽  
Cycle Fatigue

The objective of this article is to present the newest results of our research work. In order to determination and comparison of the fatigue resistance, high cycle fatigue tests (HCF) were performed both on SSAB WELDOX 700E (S690QL) quenched and tempered and VOESTALPINE ALFORM 960M (S960TM) thermomechanical high strength steels. Welded joints were made from these base materials, using gas metal arc welding (GMAW, MIG/MAG) with matching filler material. In the article, the performance of the welding experiments will be presented, especially with the difficulties of the filler material selection; along with the results of the HCF tests executed on the base material and its welded joints. Furthermore, our results will be compared with different literary data.

The Influence of Mismatch Effect on the High Cycle Fatigue Resistance of High Strength Steel Welded Joints

2018 ◽  
Vol 1146 ◽  
pp. 73-83 ◽  
Author(s):  
Ádám Dobosy ◽  
Marcell Gáspár ◽  
János Lukács
Keyword(s):  
Fatigue Resistance ◽  
Welded Joints ◽  
High Cycle Fatigue ◽  
Research Work ◽  
High Strength Steels ◽  
High Strength ◽  
Cycle Fatigue ◽  
Matching Problem ◽  
Work Related ◽  
Base Materials

The objective of this article is to present the newest results of our research work related to the high cycle fatigue resistance of advanced high strength steels. In order to determine and compare the fatigue resistance, high cycle fatigue (HCF) tests were performed on two strength categories (S690 and S960) of high strength steels including quenched and tempered (Q+T) and thermomechanical (TM) types. During the HCF tests base materials and their welded joints were investigated at different mismatch conditions (matching, undermatching, overmatching). Measured and analysed data about base materials and welded joints were compared and discussed. Statistical approach was applied during the preparation and the evaluation of the investigations, which increased their reliability. The parameters of the HCF design curves were calculated based on the Japanese testing method (JSME S 002-1981) which uses 14 specimens. During the evaluation the results were compared with each other and with literary data. According to the presented examinations the HCF resistance of the base materials is more advantageous than the welded joints. The TM steel indicated better fatigue resistance than the quenched and tempered one of the same category. The matching problem had influence on the HCF resistance of high strength steels, depending on the strength category and the steel type.

scholarly journals Life Enhancement of Transverse Fillet Weld on Welds of HSLA S460G2+M using HFMI/PIT

2019 ◽  
Vol 8 (6) ◽  
pp. 3388-3391
Keyword(s):  
Fatigue Life ◽  
Gas Metal Arc Welding ◽  
Base Material ◽  
High Strength ◽  
Butt Joint ◽  
Fatigue Tests ◽  
Fillet Weld ◽  
Excessive Heat ◽  
Metal Arc Welding ◽  
Life Enhancement

This study deals with the fatigue life enhancement of the transverse fillet weld on welds of 10mm thickness of the high strength low alloy steel (HSLA) S460G2+M which is treated using high frequency mechanical impact tool called pneumatic impact treatment (HFMI/PIT). Initially, the plate S460g2+M is prepared with groove angles of butt joint and joined using gas metal arc welding (GMAW) with multi-pass welds followed by to weld the transverse attachment over the existing welds to produce a fillet weld on welds. Secondly, the HFMI/PIT treatment is applied on the fillet weld toe using 90Hz frequency, 6 bars of pneumatic pressure and 2 mm pin radius. Thirdly, the fatigue tests with constant amplitude loading are conducted on the untreated and treated specimens by applying 0.1 stress ratio and 55% to 75% stress loading from the yield strength of the base material. All fatigue data were evaluated based on international welding institute (IIW) commission XIII. It is found that the fatigue life of treated specimen is higher as compared with the untreated specimen. However, it is observed that an excessive heat input due to multi-pass welds has insignificant effect to the fatigue life of the untreated specimen.

Fatigue Crack Propagation Limit Curves for High Strength Steels and their Application for Engineering Critical Assessment Calculations

2014 ◽  
Vol 891-892 ◽  
pp. 563-568 ◽  
Author(s):  
János Lukács ◽  
Marcell Gaspar
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Crack Propagation ◽  
Welded Joints ◽  
Research Work ◽  
High Strength Steels ◽  
High Strength ◽  
Critical Assessment ◽  
Propagation Limit

There are different prescriptions containing fatigue crack propagation limit curves and rules for the prediction of the crack growth. The research work aimed (i) to determine fatigue crack propagation limit curves for high strength steels and their welded joints, based on the Paris-Erdogan law; (ii) to use the determined limit curves for engineering critical assessment (ECA) calculations. Experiments were performed on different high strength steels and their welded joints; and the propagating cracks in the specimens represent the different possible locations of the real cracks in the structural elements. Fatigue crack growth tests were executed byΔK-decreasing and constant load amplitude methods. The evaluation process consists of six steps, and by means of the selected values a statistical method can be proposed for determination of the limit curves. Engineering critical assessment calculations were performed on a welded structural element having crack like defects.

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.

Ab Initio Study of Weldability of a High-Manganese Austenitic Twinning-Induced Plasticity (TWIP) Steel Microalloyed with Boron

2016 ◽  
Vol 1812 ◽  
pp. 35-40 ◽  
Author(s):  
Humberto Hernández-Belmontes ◽  
Ignacio Mejía ◽  
Cuauhtémoc Maldonado
Keyword(s):  
Fusion Zone ◽  
Twip Steel ◽  
Mechanical Performance ◽  
Research Work ◽  
Base Material ◽  
High Strength Steels ◽  
High Strength ◽  
Strengthening Mechanism ◽  
Microstructural Changes ◽  
Twip Steels

ABSTRACTHigh-Mn Twinning-Induced Plasticity (TWIP) steels are advanced high-strength steels (AHSS) currently under development; they are fully austenitic and characterized by twinning as the predominant strengthening mechanism. TWIP steels have high strength and formability with an elongation up to 80%, which allows reduction in automotive components weight and fuel consumption. Since the targeted application field of TWIP steels is the automotive industry, steels need high mechanical performance with good weldability and excellent corrosion resistance. However, there is lack of information about the weldability behavior of these advanced steels. This research work aims to study the weldability of a new generation of high-Mn austenitic TWIP steels microalloyed with B. Weldability was examined using spot welds produced by Gas Tungsten Arc Welding. Microstructural changes were examined using light optical metallography. Segregation of elements in the weld joint was evaluated using point and elemental mapping chemical analysis by Scanning Electron Microscopy and Electron-Dispersive Spectroscopy; while the hardness properties were examined with Vickers microhardness testing (HV25). Experimental results show that the welded joint microstructure consists of austenitic dendritic grains in the fusion zone, and equiaxed grains in the heat affected zone. Notably, the boron microalloyed TWIP steel exhibited poor weldability, showing hot cracking. Additionally, the studied TWIP steels showed a high degree of segregation in the fusion zone; Mn and Si segregated into the interdendritic regions, while Al and C preferentially segregated in dendritic areas. Finally, the welded joints of the TWIP steels showed microhardness values lower than the base material. In general, the present TWIP steels have problems of weldability, which are corroborated with microstructural changes, elements segregation and microhardness loss.

Feasibility study of welding dissimilar Advanced and Ultra High Strength Steels

2020 ◽  
Vol 59 (1) ◽  
pp. 54-66
Author(s):  
Francois Njock Bayock ◽  
Paul Kah ◽  
Antti Salminen ◽  
Mvola Belinga ◽  
Xiaochen Yang
Keyword(s):  
Heat Input ◽  
High Strength Steel ◽  
Gas Metal Arc Welding ◽  
Base Material ◽  
Welding Process ◽  
High Strength Steels ◽  
High Strength ◽  
Hardness Test ◽  
Welding Parameter ◽  
Welding Parameters

AbstractThis study concerns the weldability of dissimilar Ultra high-strength steel (UHSS) and advanced high-strength steel (AHSS), which is used in the modern machine industry. The materials offered superior strength as well as relatively low weight, which reduces microstructure contamination during a live cycle. The choice of the welding process base of the base material (BM) and welding parameters is essential to improve the weld joint quality. S700MC/S960QC was welded using a gas metal arc welding (GMAW) process and overmatched filler wire, which was performed using three heat input (7, 10, and 15 kJ/cm). The weld samples were characterized by a Vickers-hardness test, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The test reveals a decrease of softening areas in the HAZ and the formation of the stable formation of Bainite-Ferrite for S700MC and Bainite-martensite for S960QC when the heat input of 10 kJ/cm is used. It is recommended to use the GMAW process and Laser welding (Laser beam-MIG), with an optimal welding parameter, which will be achieved a high quality of manufacturing products.

scholarly journals Effect of the Interpass Temperature on Simulated Heat-Affected Zone of Gas Metal Arc Welded API 5L X70 Pipe Joint

2021 ◽  
Author(s):  
Paulo Henrique Grossi Dornelas ◽  
João da Cruz Payão Filho ◽  
Victor Hugo Pereira Moraes e Oliveira ◽  
Diogo de Oliveira Moraes ◽  
Petrônio Zumpano Júnior
Keyword(s):  
Heat Affected Zone ◽  
Welded Joints ◽  
Oil And Gas ◽  
Thermodynamic Simulation ◽  
Gas Metal Arc Welding ◽  
High Strength ◽  
Simulation Software ◽  
Coarse Grain ◽  
Metal Arc Welding ◽  
Pipe Joint

Abstract Welding costs associated with the laying of pipes for deepwater oil and gas extraction can be reduced using high interpass temperatures (ITs). However, a high IT can decrease the mechanical properties of the heat-affected zone (HAZ) of welded joints. With the use of high strength-toughness stees, this decrease may be an acceptable trade-off. Therefore, it is necessary to evaluate the influence of high ITs on the HAZ. The influence of the IT on the coarse grain HAZ (CGHAZ) and intercritically reheated coarse-grain HAZ (ICCGHAZ) of an API 5L X70 pipe joint welded by gas metal arc welding was investigated. The welding was numerically simulated using finite element method software. The microstructure of the HAZ was predicted using thermodynamic simulation software. The CGHAZ and ICCGHAZ were also physically simulated and evaluated via optical microscopy and scanning electron microscopy, dilatometry, and Vickers microhardness and Charpy V-notch (CVN) impact tests. The increase in IT led to a decrease in CGHAZ microhardness, but did not affect the ICCGHAZ. The CVN energies obtained for all ITs (CGHAZ and ICCGHAZ) were higher than that set by the DNVGL-ST-F101 standard (50 J). These results show that increasing the IT is an interesting and effective method to reduce welding costs. In addition, thermodynamic simulation proved to be a valid method for predicting the phases in the HAZ of API 5L X70 pipe welded joints.

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