Investigation of CGHAZ During Single and Multi Pass Submerged Arc Welding of High Strength Steel

2020 ◽  
Author(s):  
Satish Kumar Sharma ◽  
Sachin Maheshwari
Keyword(s):  
Mechanical Properties ◽  
Critical Temperature ◽  
Heat Input ◽  
Arc Welding ◽  
High Strength ◽  
Submerged Arc Welding ◽  
Welding Operation ◽  
First Pass ◽  
Submerged Arc ◽  
Upper Critical Temperature

Abstract Owing to its fine structure and high strength to weight ratio, high strength low alloy (HSLA) steel, API X80, is most preferred grade for application in oil and gas pipeline fabrication. Coarse grain heat affected zone (CGHAZ) formed during fabrication of pipelines using high heat input welding operation like submerged arc welding (SAW) is the crucial area for failure during the application of welded structure. Large detrimental changes occur in mechanical behavior and microstructural characteristics of HAZ due to thermal cycles of the welding operation. In this study, CGHAZ built during first-pass of SAW and when it gets reheated during second-pass as well as third-pass is investigated at each stage for mechanical properties (impact toughness and hardness) as well as microstructural changes. Peak temperature of CGHAZ is determined using upper critical temperature limit of steel. For identifying the lower and upper critical temperature for this steel, dilatometry tests were performed and values were found in well agreement with theoretically determined ones. Comparative analysis of mechanical properties as well as microstructure in simulated HAZ with parent material is also discussed. It is found that subsequent reheating of CGHAZ (formed during first-pass of welding) because of second and third-pass of welding has beneficial effect. Work of this study will guide the engineers to put the limit on heat input in terms of number of passes during welding of such high strength pipeline steels.

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.

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

Establishment of Cold Wire Addition Technology® in Multiwire Submerged Arc Welding for Line Pipe Manufacturing to Improve the Weldment Quality

2015 ◽  
Author(s):  
Ramakrishnan Mannarsamy ◽  
S. K. Shrivastava ◽  
Piyush Thakor ◽  
Gautam Chauhan ◽  
S. K. Joshi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Weld Metal ◽  
Arc Welding ◽  
Welding Process ◽  
High Strength ◽  
Submerged Arc Welding ◽  
Line Pipe ◽  
Cold Wire ◽  
Welding Procedure ◽  
Submerged Arc

For achieving high productivity multiple wire submerged arc welding such as tandem wire, three wires and five wires submerged arc welding was introduced in recent past years. Due to adding of additional wires in a pipe mill faced process difficulties such as controlling the current supply to each wire and further challenges for consumable design in order to give effective slag characteristics and bead shape control at these higher welding speeds and heat inputs. To gain maximum productivity, welding speed must be as fast as possible (in excess of 2 m/min) consistent with reliable high speed wire feeding and the characteristics of the SAW flux considering these factors in determining the balance of heat input, penetration, bead shape, dilution, weld metal chemistry and mechanical properties such as toughness. Steels containing high strength low alloying elements like Manganese, Molybdenum, Titanium and boron have favorable physical properties such as higher subzero toughness, resistance to improve the mechanical properties because of which there is substantial saving in the material. High strength low alloy steels materials are utilized in offshore and onshore at critical services. However, such benefits can be exploited provided these steels can be welded with appropriate development of welding process such as cold wire addition® in multi wires with process controller using WINCC programmer, Z5 version to give better weldments, which will not compromise the integrity, and operating condition. To obtain higher productivity and quality, it is necessary to develop a welding procedure for butt joint of line pipe steels. This paper describes the recent work carried out by Welspun, in this regard to establish the welding procedure using GMAW and submerged arc welding process and evaluation of mechanical properties. Macro and micro structural analysis were also made to characterize the weld metal properties.

scholarly journals The Influence of Heat Input to Mechanical Properties and Microstructures of API 5L-X65 Steel Using Submerged Arc Welding Process

2019 ◽  
Vol 269 ◽  
pp. 01009 ◽  
Author(s):  
Suryana ◽  
Agus Pramono ◽  
Iskandar Muda ◽  
Ade Setiawan
Keyword(s):  
Mechanical Properties ◽  
Heat Input ◽  
Arc Welding ◽  
High Reliability ◽  
Welding Process ◽  
Submerged Arc Welding ◽  
Welding Parameters ◽  
X65 Steel ◽  
Api 5L X65 Steel ◽  
Submerged Arc

API 5L-X65 steel is the type of high strength low alloy (HSLA) steel, widely used in the manufacture of pipe. Submerged arc welding (SAW) is widely used for the fabrication of the pipe, the extent of use submerged arc welding caused it could be done automatically and high reliability. The results of the welding process will lead to differences and changes in the microstructure in heat affected zone (HAZ) and weld metal that will affect the mechanical properties of the output, so as to obtain good welding results required the selection of welding parameters accordingly. As the use of the heat input during welding is very important influence on the mechanical properties and microstructure of the weld. The purpose of this study to determine the effect of heat input on the microstructure, hardness and toughness of welds in submerged arc welding. Welding currents used were 200, 300, 400 and 500 Ampere with a voltage were used 25, 27 and 30 Volt. The results showed that the higher heat input will result in a growing area of HAZ region width and grain size increased. Highest hardness values are the results of the weld heat input with a low of 244.69 HVN caused by the rapid cooling rate of the weld area. The highest toughness values are the results of the highest heat input that was dominated by acicular ferrite phase.

scholarly journals Mechanical Properties of Weld Metal for Fire-Resistant Steel with Large Heat Input Submerged Arc Welding.

1996 ◽  
Vol 14 (1) ◽  
pp. 27-32 ◽  
Author(s):  
Kazutoshi ICHIKAWA ◽  
Yukihiko HORII ◽  
Ryuichi MOTOMATSU ◽  
Masami YAMAGUCHI ◽  
Nobutaka YURIOKA
Keyword(s):  
Mechanical Properties ◽  
Weld Metal ◽  
Heat Input ◽  
Arc Welding ◽  
Submerged Arc Welding ◽  
Resistant Steel ◽  
Large Heat ◽  
Submerged Arc ◽  
Fire Resistant Steel

Influence of Thermal Simulated and Real Tandem Submerged Arc Welding Process on the Microstructure and Mechanical Properties of the Coarse Grained Heat Affected Zone

2011 ◽  
Vol 110-116 ◽  
pp. 3191-3198
Author(s):  
Sadegh Moeinifar
Keyword(s):  
Grain Boundaries ◽  
Heat Affected Zone ◽  
Heat Input ◽  
Arc Welding ◽  
Welding Process ◽  
Submerged Arc Welding ◽  
Rolled Plate ◽  
Arc Welding Process ◽  
Submerged Arc ◽  
Tandem Submerged Arc Welding

The high-strength low-alloy microalloyed steel was procured as a hot rolled plate with accelerated cooling. The Gleeble thermal simulated process involved heating the steel specimens to the peak temperature of 1400 °C, with constant cooling rates of 3.75 °C/s and 2 °C/s to room temperature. The four-wire tandem submerged arc welding process, with different heat input, was used to generate a welded microstructure. The martensite/austenite constituent appeared in the microstructure of the heat affected zone region for all the specimens along the prior-austenite grain boundaries and between bainitic ferrite laths. The blocky-like and stringer martensite/austenite morphology were observed in the heat affected zone regions. The martensite/austenite constituents were obtained by a combination of field emission scanning electron microscopes and image analysis software The Charpy absorbed energy of specimens was assessed using Charpy impact testing at-50 °C. Brittle particles, such as martensite/austenite constituent along the grain boundaries, can make an easy path for crack propagation. Similar crack initiation sites and growth mechanism were investigated for specimens welded with different heat input values.

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