scholarly journals Weldability of Underwater Wet-Welded HSLA Steel: Effects of Electrode Hydrophobic Coatings

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1364
Author(s):  
Jacek Tomków
Keyword(s):  
Heat Affected Zone ◽  
Welded Joints ◽  
Hsla Steel ◽  
High Strength ◽  
Filler Material ◽  
Visual Test ◽  
Hydrophobic Coatings ◽  
Hydrophobic Substances

The paper presents the effects of waterproof coatings use to cover electrodes on the weldability of high-strength, low-alloy (HSLA) steel in water. With the aim of improving the weldability of S460N HSLA steel in water, modifications of welding filler material were chosen. The surfaces of electrodes were covered by different hydrophobic substances. The aim of the controlled thermal severity (CTS) test was to check the influence of these substances on the HSLA steel weldability in the wet welding conditions. The visual test, metallographic tests, and hardness Vickers HV10 measurements were performed during investigations. The results proved that hydrophobic coatings can reduce the hardness of welded joints in the heat-affected zone by 40–50 HV10. Additionally, the number of cold cracks can be significantly reduced by application of waterproof coatings on the filler material. The obtained results showed that electrode hydrophobic coatings can be used to improve the weldability of HSLA steel in underwater conditions.

scholarly journals A round-robin test with thermal simulation of the welding HAZ to draw CCT diagrams: a need for harmonized procedures and microconstituent terminologies

2014 ◽  
Vol 19 (3) ◽  
pp. 279-290 ◽  
Author(s):  
Américo Scotti ◽  
Huijun Li ◽  
Rosa M. Miranda
Keyword(s):  
Heat Affected Zone ◽  
Hsla Steel ◽  
High Strength ◽  
Round Robin ◽  
Round Robin Test ◽  
Measurement Systems ◽  
Thermal Simulations ◽  
Simulation Parameters ◽  
Cct Diagrams

Thermal simulations of heat affected zone (HAZ) have been widely used. This is an economic expedite process for phase transformation evaluations in steels when subjected to weld thermal cycles as well as to draw continuous cooling transformation (CCT) diagrams. Different approaches for the simulation and parameter settings have been used by several researchers, yet leading to not always even results. Thus, it was proposed a round-robin test trial performed by different laboratories, aiming to evidence potential sources of error or inadequacy of the approaches. A High Strength Low Alloy (HSLA) steel was used as a case study. Despite the limited number of tests, the results show low robustness when comparing the outcomes from the different laboratories and point out for the need to take three actions. The first one is to implement a cooperative and multi-institutional program to assess the effect of relevant simulation parameters, such as the heating rate and holding time at peak temperature, on the final microstructure and transformation temperatures as well as on the hardness for a given cooling rate. The second is to propose calibration procedures for the simulation and measurement systems. The third action is to stimulate experts in this area to develop a guideline of terminology for constituents in the heat affected zone of ferritic steels.

scholarly journals A Fracture Mechanics-Based Optimal Fatigue Design Method of Under-Matched HSLA Steel Butt-Welded Joints with Imperfections

2019 ◽  
Vol 9 (17) ◽  
pp. 3609 ◽  
Author(s):  
Wen ◽  
Wang ◽  
Dong ◽  
Fang
Keyword(s):  
Fracture Mechanics ◽  
Welded Joints ◽  
Design Method ◽  
Hsla Steel ◽  
High Strength Steels ◽  
High Strength ◽  
Engineering Structures ◽  
Fatigue Design ◽  
Load Carrying ◽  
Practical Engineering

The trend of light-weight structures leads to the wide application of high strength steels in engineering structures. When welding high strength steels, under-matched consumables could reduce the cold-cracking tendency, simplifying the preheating process. However, under-matched welds would sometimes make the high strength base metal pointless due to its weak load-carrying capacity. For the purpose of enhancing the fatigue strength of under-matched welded joints, a fracture mechanics-based optimal fatigue design method of under-matched butt-welded joints is proposed in this work. Heterogeneous mechanical features of welded joints, which are not considered in current standards and codes, are incorporated into the optimal design method. The fatigue limit of the high strength parent metal is taken as the design target, which has seldom been reported. HSLA steel Q550, with its under-matched consumable ER70S-6 composed X-shaped butt-welds, is selected for experimental verification. The experimental results indicate that the fracture mechanic based equal-fatigue-bearing-capacity (EFBC) design method established in this work is feasible and could be a valuable reference for the design of practical engineering structures.

Structure and ductility of the heat-affected zone of welded joints of a high-strength steel

2014 ◽  
Vol 115 (12) ◽  
pp. 1241-1248 ◽  
Author(s):  
T. I. Tabatchikova ◽  
A. D. Nosov ◽  
S. N. Goncharov ◽  
N. Z. Gudnev ◽  
S. Yu. Delgado Reina ◽  
...  
Keyword(s):  
Heat Affected Zone ◽  
Welded Joints ◽  
High Strength Steel ◽  
High Strength

Optimization of the structure and properties of the heat-affected zone of welded joints in high-strength pipe steels

2015 ◽  
Vol 29 (9) ◽  
pp. 712-717 ◽  
Author(s):  
A.A. Velichko ◽  
V.V. Orlov ◽  
U.A. Pazilova ◽  
R.V. Sulyaguin ◽  
E.I. Khlusova
Keyword(s):  
Heat Affected Zone ◽  
Welded Joints ◽  
High Strength ◽  
Structure And Properties ◽  
Pipe Steels

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.

scholarly journals DIFFUSION OF HYDROGEN IN WELDED JOINTS OF STRUCTURAL STEELS

2017 ◽  
Vol 21 (6) ◽  
pp. 85-95 ◽  
Author(s):  
N. N. Sergeev ◽  
A. N. Sergeev ◽  
S. N. Kutepov ◽  
A. E. Gvozdev ◽  
E. V. Ageev
Keyword(s):  
Diffusion Coefficient ◽  
Weld Metal ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Chemical Potential ◽  
Weld Zone ◽  
Base Material ◽  
High Strength ◽  
Low Alloy Steels ◽  
Alloy Steels

High-strength low-alloy steels are widely used in the construction of welded metal structures. The main advantage of these steels is good combination of strength and toughness, and weldability. However, when welding high strength low alloy steels during cooling of the weld to a temperature below 150-100 °C there may be a risk of formation of bulk crystal structures defects in the weld zone - cold cracks. It was experimentally established that one of the factors contributing to the formation of cold cracks may be the occlusion of hydrogen in the atmosphere of arc plasma in the solidifying weld metal, from which diffusion hydrogen may diffuse to different areas of the weld after cooling. Hydrogen cracking typically has a tendency to slow down i.e. cracks can occur several days after the completion of welding process. As a rule, hydrogen induced cracking occurs either in the original steel in the heat-affected zone or in the weld metal, which is important, topical and long been researched by various scientific schools. Modern technologies of high strength low alloy steels processing have significantly improved the quality of the base material by reducing the amount of carbon and impurities, which has increased the stability of weld in the heat affected zone (HAZ) to hydrogen induced cold cracking. The paper presents modern approaches to the definition of diffusion coefficient of hydrogen in welded joints of high-strength low-alloy steels. Taking into account the temperature, the gradient of chemical potential and continuity conditions there has been considered the process of mass transfer of hydrogen under the influence of diffuse inhomogeneous mediums. It has been shown that the local effects of changing pressure and chemical potential are described using the equation of generalized potential of the diffusing substance. Our paper presents analytical expressions to determine the apparent diffusion coefficient of hydrogen in different local areas of a welded joint depending on temperature.

scholarly journals STRENGTH AND FRACTURE TOUGHNESS OF THE WELDED JOINTS MADE OF HIGH-STRENGTH FERRITIC STEEL

2013 ◽  
Vol 7 (4) ◽  
pp. 226-229 ◽  
Author(s):  
Ihor Dzioba ◽  
Tadeusz Pała ◽  
Ilkka Valkonen
Keyword(s):  
Fracture Toughness ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Ferritic Steel ◽  
Base Material ◽  
High Strength ◽  
Experimental Results ◽  
Strength Characteristics ◽  
Fusion Line ◽  
Weld Material

Abstract The paper presents experimental results of the characteristics of strength and fracture toughness of the material from the different zones of welded joints made of different participation of the linear welding energy. Strength characteristics and fracture toughness were determined in the weld material, in the area of fusion line, in the material of the heat affected zone and in the base material

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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