Enhanced Impact Toughness of Heat Affected Zone in Gas Shield Arc Weld Joint of Low-C Medium-Mn High Strength Steel by Post-Weld Heat Treatment

2017 ◽  
Vol 89 (4) ◽  
pp. 1700422 ◽  
Author(s):  
Xiangyu Qi ◽  
Linxiu Du ◽  
Jun Hu ◽  
R. Devesh Kumar Misra
Keyword(s):  
Heat Treatment ◽  
Impact Toughness ◽  
Weld Joint ◽  
Heat Affected Zone ◽  
High Strength Steel ◽  
High Strength ◽  
Post Weld Heat Treatment ◽  
Weld Heat

scholarly journals Impact Toughness of Gas Metal Arc Welded HY-80 Steel Plate at Sub-zero Temperatures

2019 ◽  
Vol 269 ◽  
pp. 06003
Author(s):  
Herry Oktadinata ◽  
Winarto Winarto
Keyword(s):  
Impact Toughness ◽  
Weld Joint ◽  
Heat Affected Zone ◽  
High Strength Steel ◽  
Steel Plate ◽  
Gas Metal Arc Welding ◽  
High Strength ◽  
Coarse Grain ◽  
Fracture Appearance ◽  
The Impact

Various welding methods are widely applied in large fabrication of high strength steel. However, commonly the problem occurs where a coarse grain is formed near fusion zone causing reduce the impact toughness due to the weld joint become brittle. Ductility and toughness in a coarse grain heat affected zone (CGHAZ) is low due to the formation of coarsening grain size. The objective of this research is to investigate the microstructure evolution, impact toughness and fracture appearance at sub-zero temperatures of the high strength steel arc welded. The steel that used in this experiment is a HY-80 steel welded by gas metal arc welding (GMAW) with a mixture of argon and carbon dioxide (90%Ar and 10%CO2) and ER100S solid wire. Microstructure observation and Charpy V-notch (CVN) tests were performed on the weld joint which consist of base metal (BM), heat affected zone (HAZ), and weld metal (WM). The CVN tests on the HY-80 steel plate at various temperatures (20, -20, -60 and -80 °C) show impact toughness decrease when the test temperature decrease. The CVN tests on the HY-80 weld joint at a temperature of 80 °C show the lowest impact toughness was measured at WM (61 J) and followed fusion line-FL (101 J) with brittle fracture appearance.

Evaluation on Chloride Cracking of S135 High-Strength Drill Pipe

2012 ◽  
Vol 430-432 ◽  
pp. 636-639
Author(s):  
Zhang Zhi ◽  
Xiao Yu Zhou ◽  
De Zhi Zeng ◽  
Ji Yin Zhang ◽  
Tai He Shi
Keyword(s):  
Heat Treatment ◽  
Weld Joint ◽  
Friction Welding ◽  
Drilling Fluid ◽  
Drill Pipe ◽  
High Strength ◽  
Chloride Ions ◽  
Post Weld Heat Treatment ◽  
Uniform Corrosion ◽  
Weld Heat

During the process of deep drilling with high temperature and high pressure, downhole drilling tools might be exposed to various corrosive mediums, such as water/oil-based drilling fluid systems, dissolved oxygen, H2S/CO2, halogen elements (Cl- and Br-), etc. Halogen elements existing in the drilling fluid are ions promoting corrosion of metals. This effect is mainly manifested in the forms of uniform corrosion, pitting corrosion, stress corrosion cracking, etc. of carbon steel. Quality of the drill pipe is determined by the DP body, joint and welding area of the drill pipe. Reasonable friction welding process and proper post weld heat treatment can make the mechanical property of weld joint satisfy related standards. If process of friction welding or post weld heat treatment is improper, the weld joint will be easily damaged and accidents of pricking, breaking, etc will be likely aroused. This paper carries out an evaluation experiment of chloride cracking on the DP body, joints and weld joints of the high-strength drill pipe (S135) and discusses corrosion of the high-strength drill pipe caused by chloride ions.

scholarly journals Metallurgical Effects of Niobium and Molybdenum on Heat-Affected Zone Toughness in Low-Carbon Steel

2019 ◽  
Vol 9 (9) ◽  
pp. 1847 ◽  
Author(s):  
Hardy Mohrbacher
Keyword(s):  
Heat Treatment ◽  
Heat Affected Zone ◽  
High Strength ◽  
Post Weld Heat Treatment ◽  
Coarse Grained ◽  
Accelerated Cooling ◽  
Low Carbon ◽  
Structural Applications ◽  
Steel Grades ◽  
Weld Heat

Modern weldable high strength steel grades are typically based on low-carbon alloy concepts using microalloying for obtaining a good strength-toughness balance. Such steel grades having a yield strength in the range of 420 to 690 MPa are very commonly used in pipelines, heavy vehicles, shipbuilding and general structural applications. Thermomechanical processing during hot rolling combined with accelerated cooling is an established means of producing such steel grades. Considering the alloying concepts, the use of niobium and molybdenum, and in selected cases boron, is very efficient to achieve high strength and good toughness. However, all targeted applications of such high strength steels involve extensive welding. Thus, heat affected zone properties are of particular importance. The present paper investigates the effects of Nb, Mo and Ti on the heat affected zone properties. Variations of the Mn and Si contents are considered as well. Additionally, the influence of post-weld heat treatment in the coarse-grained heat-affected zone (HAZ) is considered. In this approach, HAZ subzones were generated using laboratory weld cycle simulations in combination with systematic variation of alloying elements to scrutinize and interpret their specific effects. The results indicate that Mo and Nb, when alloyed in the typical range, provide excellent HAZ toughness and guarantee sufficiently low ductile-to-brittle transition temperature. An alloy combination of Nb, Mo and Ti improves performance under hot deformation conditions and toughness after post-weld heat treatment.

Evaluation of Cracking Behavior of SPV50Q High Strength Steel Weldment in Wet H2S Containing Environment

2005 ◽  
Vol 297-300 ◽  
pp. 951-957 ◽  
Author(s):  
Jian Ming Gong ◽  
Jian Qun Tang ◽  
Xian Chen Zhang ◽  
Shan Tung Tu
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
High Strength Steel ◽  
High Strength ◽  
Post Weld Heat Treatment ◽  
Welding Residual Stress ◽  
Cracking Behavior ◽  
Steel Weldment ◽  
Hydrogen Induced Cracking ◽  
Weld Heat

JIS-SPV50Q high strength steel is often employed in construction of liquid petroleum gas (LPG) spherical tanks due to its high strength and good ductility. In general, post weld heat treatment is not performed after welding of SPV50Q high strength steel and welding residual stress will be retained in weldment. Service experience and inspection indicate that higher H2S concentration and welding residual stress result in the environmental failure, such as blistering or hydrogen induced cracking (HIC), sulfide stress corrosion cracking (SSCC) and stress oriented hydrogen induced cracking (SOHIC). In the present paper, the cracking behavior of SPV50Q high strength steel weldment by manual electric arc welding has been investigated in various saturate solutions with different concentrations of H2S. The results of slow strain rate testing, performed at a strain of 1×10-6s-1, reveal the presence of SSCC and HIC in the base metal adjacent to HAZ. The ffects of the different temperatures of post weld heat treatment on cracking are discussed. The suitable post weld heat treatment could increase the resistance of SPV50Q weldment on SSCC or HIC and does not decrease the mechanical properties of SPV50Q weldment.

Effects of Post-Weld Heat Treatment on Optimum Cathodic Protection Potential of High-Strength Steel in Marine Environment Conditions

2005 ◽  
Vol 486-487 ◽  
pp. 133-136 ◽  
Author(s):  
Seong Jong Kim ◽  
Seok Ki Jang ◽  
Jeong Il Kim
Keyword(s):  
Heat Treatment ◽  
High Strength Steel ◽  
High Strength ◽  
Post Weld Heat Treatment ◽  
Test Method ◽  
Slow Strain Rate Test ◽  
Treatment Conditions ◽  
Time To Fracture ◽  
Protection Potential ◽  
Weld Heat

The electrochemical and mechanical properties of welded high-strength steel were investigated using the slow strain rate test method with a constant applied cathodic potential. No correlations were found with the maximum tensile strength, yield strength, stress at failure, or hydrogen embrittlement. However, the elongation, time-to-fracture, and strain-to-failure ratio decreased as the potential became more negative. These parameters were greatest when the potential was -770mV, regardless of the post-weld heat treatment conditions. The elongation and time-to-fracture increased with PWHT.

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