scholarly journals Weldability and Lamellar Tearing Susceptibility of High-Strength SN 490C Steel Plates

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 551 ◽  
Author(s):  
Donghyun Van ◽  
Seung Hwan Lee ◽  
Kihyuk Kim ◽  
Hoseop Sim
Keyword(s):  
Arc Welding ◽  
High Strength ◽  
Steel Plates ◽  
Hardness Profile ◽  
Building Structures ◽  
Heat Effects ◽  
Flux Cored Arc Welding ◽  
Lamellar Tearing ◽  
The Impact ◽  
Submerged Arc

In this study, weldability and cracking susceptibility of SN 490C steel were firstly investigated. For this study, SN 490C thick plates which had been developed for anti-seismic steel of building structures were welded by flux-cored arc welding (FCAW) and submerged arc welding (SAW) processes based on welding conditions of actual construction site. Weldments using the plates with different thickness were produced using E71T-1C and EH14 filler wires, respectively. For the weldability tests, various welded joints such as butt and T-joints were examined. After welding, microstructure analysis was performed. Various microstructures were found depending on the location of the weldments. Heat effects by multi-pass welding were correlated with the microstructure. The microstructure was correlated with the hardness profile and the impact test result. In addition, the through-thickness tensile test, window test, and Cranfield test were conducted to evaluate sensitivity of lamellar tearing, which may occur during tensile restraint stress of welds. As a result of the tests, it was found that the SN 490C steel was sufficiently resistant to lamellar tearing.

Mechanical Behaviour of Welded Joints Achieved by Multi-Wire Submerged Arc Welding

2017 ◽  
Vol 1143 ◽  
pp. 52-57
Author(s):  
Elena Scutelnicu ◽  
Carmen Catalina Rusu ◽  
Bogdan Georgescu ◽  
Octavian Mircea ◽  
Melat Bormambet
Keyword(s):  
Mechanical Behaviour ◽  
Welded Joints ◽  
Arc Welding ◽  
Base Material ◽  
High Strength ◽  
Submerged Arc Welding ◽  
Steel Plates ◽  
Wire Saw ◽  
Api 5L X70 Steel ◽  
Submerged Arc

The paper addresses the development of advanced welding technologies with two and three solid wires for joining of HSLA API-5l X70 (High-strength low-alloy) steel plates with thickness of 19.1 mm. The experiments were performed using a multi-wire Submerged Arc Welding (SAW) system that was developed for welding of steels with solid, tubular and cold wires, in different combinations. The main goal of the research was to assess the mechanical performances of the welded joints achieved by multi-wire SAW technology and then to compare them with the single wire variant, as reference system. The welded samples were firstly subjected to NDT control by examinations with liquid penetrant, magnetic particle, ultrasonic and gamma radiation, with the aim of detecting the specimens with flaws and afterwards to reconsider and redesign the corresponding Welding Procedure Specifications (WPS). The defect-free welded samples were subjected to tensile, Charpy V-notch impact and bending testing in order to analyse and report the mechanical behaviour of API-5l X70 steel during multi-wire SAW process. The experimental results were processed and comparatively discussed. The challenge of the investigation was to find the appropriate welding technology which responds simultaneously to the criteria of quality and productivity. Further research on metallurgical behaviour of the base material will be developed, in order to conclude the complete image of the SAW process effects and to understand how the multi-wire technologies affect the mechanical and metallurgical characteristics of the API-5L X70 steel used in pipelines fabrication.

Microstructure and Mechanical Properties of Extra High Strength Heavy Steel Plate for Bridge Application

2014 ◽  
Vol 783-786 ◽  
pp. 859-866 ◽  
Author(s):  
Dong Sheng Liu ◽  
Chong Xiang Yue ◽  
Huan De Chen ◽  
Bing Gui Cheng
Keyword(s):  
Mechanical Properties ◽  
Arc Welding ◽  
Steel Plate ◽  
Control Process ◽  
High Strength ◽  
Submerged Arc Welding ◽  
Steel Plates ◽  
Weathering Steel ◽  
Weld Joints ◽  
Submerged Arc

Key parameters for thermomechanical control process (TMCP) and integrated welding operations have been determined to industrialize extra high strength micro-alloyed low carbon SiMnCrMoNiCu steel plates for bridge applications. Confocal Scanning Microscope was used to make In-situ observation on austenite grain growth during reheating. A Gleeble 3800 thermomechanical simulator was employed to investigate transformation behavior of the TMCP conditioned austenite. Integrated industrial rolling trial was conducted to correlate the laboratory observations and commercial production of the plates. Microstructure factors affecting the toughness of the steel were analyzed. Submerged-Arc Welding (SMAW) trails were conducted and the structures and mechanical properties of the weld joints characterized. The representative plate with thickness of 60 mm consisted of acicular ferrite (AF) + refined polygonal ferrite (PF) + granular bainite (GB) across the entire thickness section exhibit yield strength (YS) greater than 560 MPa in transverse direction and excellent Charpy V Notch (CVN) impact toughness greater than 100 J at-40 °C in the parent metal and the weld joints. These provide useful integrated database for producing advanced high strength steel plates via TMCP. Keywords: Thermo-Mechanical Control Process;Weathering Steel Plate for Bridge; Submerged-Arc Welding without Preheating

Development of Welding Procedures for X90-Grade Seamless Pipes for Riser Applications

2012 ◽  
Author(s):  
Hiroyuki Nagayama ◽  
Masahiko Hamada ◽  
Mark F. Mruczek ◽  
Mark Vickers ◽  
Nobuyuki Hisamune ◽  
...  
Keyword(s):  
Weld Metal ◽  
Arc Welding ◽  
Mechanical Test ◽  
Welding Process ◽  
High Strength ◽  
Submerged Arc Welding ◽  
Welding Parameters ◽  
Flux Cored Arc Welding ◽  
Welding Procedure ◽  
Submerged Arc

Ultra-high strength seamless pipes of X90 and X100 grades have been developed for deepwater or ultra-deepwater applications. Girth welding procedure specifications (WPSs) should be developed for the ultra-high strength pipes. However, there is little information for double jointing welding procedure by using submerged arc welding process for high strength line pipes. This paper describes mechanical test results of submerged arc welding (SAW) and gas shielded flux cored arc welding (GSFCAW) trials with various welding consumables procured from commercial markets. Welds were then made with typical welding parameters for riser productions using high strength X90 seamless pipes. The submerged arc weld metal strength could increase by increasing alloy elements in weld metal. The weld metal with CE (IIW) value of 0.74 mass% achieved fully overmatching for the X90 pipe. The weld metal yield strength (0.2% offset) was 694 MPa, and the ultimate tensile strength was 833 MPa. It was also confirmed that the reduction of boron in weld metal can improve low temperature toughness of high strength weld metal. Furthermore, it was confirmed that the HAZ has excellent mechanical properties and toughness for riser applications. In this study GSFCAW procedures were also developed. GSFCAW can be used for joining pipe and connector material for riser production welding. The weld metal with a CE (IIW) value of 0.54 mass% could meet the required strength level for X90-grade pipe as specified in ISO 3183. Cross weld tensile testing showed that fractures were achieved in the base metal. Good Charpy impact properties in weld metal and HAZ were also confirmed.

scholarly journals Impact resistance of steel materials to ballistic ejecta and shelter development using steel deck plates

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Hiroyuki Yamada ◽  
Kohei Tateyama ◽  
Shino Naruke ◽  
Hisashi Sasaki ◽  
Shinichi Torigata ◽  
...  
Keyword(s):  
Impact Energy ◽  
Impact Test ◽  
Impact Resistance ◽  
Protective Layer ◽  
High Strength ◽  
Steel Plates ◽  
Corrugated Plates ◽  
Shelter Construction ◽  
The Impact ◽  
Ballistic Ejecta

AbstractThe destruction caused by ballistic ejecta from the phreatic eruptions of Mt. Ontake in 2014 and Mt. Kusatsu-Shirane (Mt. Moto-Shirane) in 2018 in Japan, which resulted in numerous casualties, highlighted the need for better evacuation facilities. In response, some mountain huts were reinforced with aramid fabric to convert them into shelters. However, a number of decisions must be made when working to increase the number of shelters, which depend on the location where they are to be built. In this study, we propose a method of using high-strength steel to reinforce wooden buildings for use as shelters. More specifically, assuming that ballistic ejecta has an impact energy of 9 kJ or more, as in previous studies, we developed a method that utilizes SUS304 and SS400 unprocessed steel plates based on existing impact test data. We found that SUS304 is particularly suitable for use as a reinforcing material because it has excellent impact energy absorption characteristics due to its high ductility as well as excellent corrosion resistance. With the aim of increasing the structural strength of steel shelters, we also conducted an impact test on a shelter fabricated from SS400 deck plates (i.e., steel with improved flexural strength provided by work-hardened trapezoidal corrugated plates). The results show that the shelter could withstand impact with an energy of 13.5 kJ (2.66 kg of simulated ballistic ejecta at 101 m/s on impact). In addition, from the result of the impact test using the roof-simulating structure, it was confirmed the impact absorption energy is further increased when artificial pumice as an additional protective layer is installed on this structure. Observations of the shelter after the impact test show that there is still some allowance for deformation caused by projectile impact, which means that the proposed steel shelter holds promise, not only structurally, but also from the aspects of transportation and assembly. Hence, the usefulness of shelters that use steel was shown experimentally. However, shelter construction should be suitable for the target environment.

The Benefits of a Modified-Chemistry, High-Strength, Low-Alloy Steel

1987 ◽  
Vol 3 (02) ◽  
pp. 111-118
Author(s):  
John C. West
Keyword(s):  
Heat Input ◽  
Arc Welding ◽  
High Strength ◽  
Submerged Arc Welding ◽  
Low Alloy Steel ◽  
Labor Costs ◽  
Lower Strength ◽  
The Cost ◽  
High Degree ◽  
Submerged Arc

Steels with 50 ksi and up yield points usually acquire their strength from some form of heat treatment. Most of these steels, 11/2 in. thick and up, must be welded using sustained preheat and controlled interpass temperatures, plus controlled welding heat input of approximately 50 to 60 kJ/in. These two items can add as much as 50 percent to the cost of submerged-arc welding, and increases of up to 30 percent are common for manual welding when compared with lower-strength steels previously used. To reduce costs, a quenched and precipitation-hardened steel, ASTM A710 Grade A Class 3, with a high degree of weldability, was tested. This steel, which can be welded without sustained preheat and almost unlimited heat input, has been extensively tested in thicknesses from 21/4 through 6 in. Although this steel costs more than the usual quenched-and-tempered plates at these strength levels, reductions of 40 to 75 percent in welding labor costs are probable. In addition, sizeable material savings should be realized when these items are used in place of HY-80 and HY-100.

scholarly journals A New Approach to the Study of Multi-Pass Welds–Microstructure and Properties of Welded 20-mm-Thick Superduplex Stainless Steel

2019 ◽  
Vol 9 (6) ◽  
pp. 1050 ◽  
Author(s):  
Maria Valiente Bermejo ◽  
Kjell Hurtig ◽  
Daniel Eyzop ◽  
Leif Karlsson
Keyword(s):  
Stainless Steel ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Secondary Phases ◽  
Σ Phase ◽  
Flux Cored Arc Welding ◽  
Welding Sequence ◽  
Superduplex Stainless Steel ◽  
Secondary Austenite ◽  
The Impact

Type 2507 superduplex stainless steel 20 mm in thickness was multi-pass-welded with Gas Metal Arc Welding (GMAW) and Flux-Cored Arc Welding (FCAW) processes. Recommended and higher arc energies and inter-pass temperatures were used. Thermal cycles were monitored using a recently developed procedure involving the successive instrumentation of the multi-pass welds, pass by pass, by addition of thermocouples in each weld pass. The repeatability of temperature measurements and survival rate of more than 90% of thermocouples confirmed the reliability of the procedure. Reheating by subsequent passes caused a progressive increase in the austenite content of the weld metal. The as-deposited GMAW passes with higher-than-recommended arc energy showed the lowest presence of nitrides. Therefore, the cooling rate—and not the time exposed at the critical temperature range—seems to be the key factor for nitride formation. The welding sequence layout also plays an important role in the distribution of secondary phases. A larger amount and concentration of secondary austenite and σ-phase was found for a larger number of subsequent passes in the immediate vicinity of a specific weld pass. The impact toughness exceeded requirements for all welds. Differences in absorbed energies were related to the amount of micro-inclusions found with the FCAW weld showing the lowest absorbed energies and highest amount of micro-inclusions. Pitting corrosion preferentially initiated in locations with secondary austenite and σ-phase. However, in the absence of these secondary phases, the HAZ containing nitrides was the weakest location where pitting initiated. The results of this work have implications on practical welding for superduplex stainless steels: the current recommendations on maximum arc energy should be revised for large thickness weldments, and the importance of the welding sequence layout on the formation of secondary phases should be considered.

scholarly journals RESIDUAL STRENGTH OF STRUCTURAL STEELS: SN400, SM520 AND SM570

2016 ◽  
Author(s):  
In-Rak Choi ◽  
Kyung-Soo Chung
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperatures ◽  
High Strength Steels ◽  
High Strength ◽  
Building Construction ◽  
Steel Plates ◽  
Seismic Resistance ◽  
Building Structures ◽  
Reliable Performance ◽  
Strength And Stiffness

<p>This paper presents post-fire mechanical properties of mild to high-strength steels commonly used in building structures in Korea. Steel is one of the main materials for building construction due to fast construction, light weight, and high seismic resistance. However, steel usually loses its strength and stiffness at elevated temperatures, especially over 600°C. But steel can regain some of its original mechanical properties after cooling down from the fire. Therefore, it is important to accurately evaluate the reliable performance of steel to reuse or repair the structures. For this reason, an experimental study was performed to examine the post-fire mechanical properties of steel plates SN400, SM520 and SM570 after cooling down from elevated temperatures up to 900°C. The post-fire stress-strain curves, elastic modulus, yield and ultimate strengths and residual factors were obtained and discussed.</p>

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