Metallurgical and Mechanical Features of API 5L X65 Pipeline Steel Weldment

2002 ◽  
Author(s):  
Jang-Bog Ju ◽  
Jung-Suk Lee ◽  
Jae-Il Jang ◽  
Woo-Sik Kim ◽  
Dongil Kwon
Keyword(s):  
Mechanical Properties ◽  
Base Metal ◽  
Welded Joints ◽  
Pipeline Steel ◽  
Steel Structures ◽  
Welding Residual Stress ◽  
Engineering Structures ◽  
Steel Weldment ◽  
Mechanical Factors ◽  
Fracture Performance

Substantial differences amongst metallurgical and mechanical properties of base metal (BM), weld metal (WM) and heat-affected zone (HAZ) occur in general in welded steel structures It is common practice in various engineering structures to evaluate the fracture performance of welded structures by mechanical testing. Especially, the HAZ of steel welded joints shows a gradient of microstructure and mechanical properties from the fusion line to the unaffected base metal. This study is concerned with the effects of metallurgical and mechanical factors on the fracture performance of API 5L X65 pipeline steel weldments, as they are generally used for main natural gas transmission pipelines in Korea. First of all, we investigated the microscopic and macroscopic fracture behavior of the various micro-zones within the HAZ from the viewpoint of metallurgical factors. The effects of mechanical factors such as welding residual stress in steel weldment and strength mismatch between BM and WM, particularly in high strength steel weldments, are also analyzed. Therefore, the fracture performance of API 5L X65 pipeline steel weldment was mainly dependent on the change of macrostructure and its distribution in the welded joints.

Welding Residual Stress Evaluation of Complex Welded Joints by Brinell Hardness Method

2014 ◽  
Vol 496-500 ◽  
pp. 2444-2451
Author(s):  
Qiang Zeng ◽  
Dai Qin Tao ◽  
Zheng Zhou ◽  
Xiao Qian Li
Keyword(s):  
Residual Stress ◽  
Statistical Analysis ◽  
Base Metal ◽  
Welded Joints ◽  
Brinell Hardness ◽  
Welding Residual Stress ◽  
Stress Evaluation ◽  
Material Hardness

Basing on a giant truss, this passage did a macro assessment of welding resjdual stress by the changes of material hardness which was measured by brinell hardness method after welding. This experiment measured about 1728 measurement points on 72 nodes. Statistical analysis of the hardness data shows that hardness of base metal decreases in the area of HAZ ,and plastic of welded joints increases.

Determination of Dynamic Characteristics of Welded Joints Made of Steel S460NL

2014 ◽  
Vol 224 ◽  
pp. 267-275 ◽  
Author(s):  
Wiesław Barnat ◽  
Marek Kordys
Keyword(s):  
Plastic Deformation ◽  
Dynamic Characteristics ◽  
Welded Joints ◽  
High Speed ◽  
Steel Structures ◽  
Basic Material ◽  
Engineering Structures ◽  
Static Tests ◽  
Very High

Examination of the behavior of materials under very high speed plastic deformation are widely used during the designing process of dynamically loaded steel structures. Steel is widely used as a basic material for designing engineering structures. Characteristics of steel obtained under static experiments are different from those obtained during static tests.

Tensile Strength of Forged Ti-6Al-4V Welded Joints by Electronic Beam Welding

2011 ◽  
Vol 255-260 ◽  
pp. 132-136
Author(s):  
Hong Yu Qi ◽  
Jian Xie ◽  
Dong Pan ◽  
Shao Lin Li ◽  
Xiao Guang Yang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Base Metal ◽  
Welded Joints ◽  
Empirical Relationship ◽  
Weld Zone ◽  
Structure Design ◽  
Microstructure And Mechanical Properties ◽  
Welded Structure ◽  
Static Tensile

Forged Ti-6Al-4V welded structure by electronic beam welding (EBW) as integrally bladed disk (blisk) structure in advanced aero-engine has been widely applied. It is necessary to analyze microstructure and mechanical properties of Ti-6Al-4V welded joints by EBW for failure analysis and structure design of blisk. Firstly the microstructure and mechanical properties of forged Ti-6Al-4V welded joints was focused on. Grains in the weld zone become coarse and large gradient organization structure appears in the heat affected zone (HAZ), which presents significant local heterogeneity. Microhardness of the weld zone is about 20% higher than that of the base metal. The size of different region of the welded joints was estimated. Then static tensile test of three different specimens were carried on. Experiment results show that the tensile and yield strength of welded joints are not less than that of the base metal. Finally the empirical relationship between strength and hardness of Ti-6Al-4V alloy is established. Tensile strength of the weld zone and the base metal were estimated. Compared to experiment data, the deviation is 3.56%, 0.097% respectively.

scholarly journals Effect of Alloying Composition on Microstructure and Mechanical Properties of Ultranarrow Gap Welded Joints of U71Mn Rail Steel

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Lian Gong ◽  
Hui Liu ◽  
Cheng Lv ◽  
Lijun Zhao
Keyword(s):  
Mechanical Properties ◽  
Base Metal ◽  
Welded Joints ◽  
Alloy Composition ◽  
Rail Steel ◽  
Base Material ◽  
Average Hardness ◽  
Microstructure And Mechanical Properties ◽  
Fine Pearlite ◽  
The Impact

A new welding method, ultranarrow gap welding with constrained arc by flux band, is proposed to compensate for the low quality of rail thermite welded joints. This article presents the results of research on the microstructure and mechanical properties of ultranarrow gap welded joints of U71Mn rail steel made using three types of alloying composition content flux bands. Results indicated that the base metal metallographic microstructure consisted mainly of pearlitic, the HAZ was mainly composed of fine pearlite, and the microstructure of the welded bead was composed of acicular ferrite, while the weld grain size decreased as the alloy composition increased. The average hardness noticeably changed in weld metal as the alloy composition increased, and when the alloy composition reached 19%, the hardness was equivalent to the base material. The average hardness value of the HAZ (35.8 HRC) was higher than that of the base metal (24.8 HRC). The tensile strength increased, and the percentage elongation after fracture decreased with increasing alloying composition from 9% to 19%. The impact absorbing energies were decreased as the alloying composition increased. Consequently, all the mechanical properties of rail ultranarrow gap welding were higher than those of the standard requirements of the rail flash welding. And the optimal alloying composition of flux band was 19%.

The Effect of Stand - Off Distance on the Mechanical Properties of TIG Butt Joints of 316 Stainless Steel

2020 ◽  
Vol 833 ◽  
pp. 59-65
Author(s):  
Hala M. Gnedi ◽  
Khawla T. Snoussi ◽  
Abulmaali M. Taher ◽  
Thoria G. Sharef ◽  
Yousef Arebi
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Base Metal ◽  
Welded Joints ◽  
Hardness Test ◽  
Scanning Speed ◽  
Geometrical Parameters ◽  
Worst Case ◽  
316 Stainless Steel ◽  
Hardness Values

The objective of this study is to investigate and determine the effect of the stand-off distance (distance between the welded plates) on the mechanical properties of the Tungsten Inert Gas (TIG) welded joints. Butt TIG welding was performed for 316 stainless steel (SS) by using different pre welding stand-off distances with fixing the other parameters (thickness of welded plates, voltage, current, groove shape, and scanning speed). The influence of the stand-off distance parameter was examined by using tensile test, hardness test in the three different regions (base metal, heat effected zone, and molten zone), non-destructive testing (including visual inspection, liquid pentrant and X – ray) and microscopic examinations. Results show that the stand-off distance is one of the most important geometrical parameters of the Butt welded joints to end by good mechanical properties. It is found that the optimum stand-off distance was about 1 mm (shows the highest hardness results), but still there were some defects in some spots in the molten metal zone which caused a decrease in the hardness values in these locations. The 2 mm stand-off distance shows reasonable results, and the worst case was recorded for the 0 mm stand-off distance condition. Generally the hardness values of the heat affected zone in all conditions were the highest when compared to both metal welding zone and the base metal zone.

Mechanical properties of welded joints of the pressed aluminum-magnesium 1565Ch alloy at low and high temperatures

2019 ◽  
pp. 57-67
Author(s):  
S. A. Zykov ◽  
V. I. Pavlova ◽  
E. P. Osokin
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperature ◽  
Low Temperature ◽  
Base Metal ◽  
Welded Joints ◽  
Arc Welding ◽  
Cryogenic Temperature ◽  
Actual Strength ◽  
Temperature Hardening ◽  
Consumable Electrodes

The paper studies structure and mechanical properties of welded joints of hot-pressed panels and profiles manufactured by JSC Arkonik SMZ from aluminum-magnesium 1565ch alloy at the temperature range of –165 to 150°C. It is established that the nature of changes in the properties of welded joints of pressed panels and profiles of 1565ch alloy made by manual argon-arc welding with non-consumable electrodes of ArDS with filler material SwAMg-61 at various test temperatures is similar to changes of welded joints of rolled sheets. When the test temperature is lowered, low-temperature hardening of the welded joints takes place – at a cryogenic temperature (–165°C), 20–30% of strength is gained comparing to 20°C. The prolonged aging of welded joints at an elevated temperature (150°C) leads to strength decrease by 25–30% compared to that of 20°C. The coefficient of strength of welded joints with reinforced joint is not less than 0.9 of the actual strength of the base metal at all test temperatures.

scholarly journals INFLUENCE OF THE CHEMICAL COMPOSITION AND METHOD OF SMELTING ON THE PROPERTIES OF THE METAL OF WELDED JOINTS OF ECONOMICALLY ALLOYED CHROMIUM-MANGANESE-NICKEL STEELS

2021 ◽  
pp. 69-73
Author(s):  
O. P. Bondareva ◽  
E. V. Sedov ◽  
O. B. Kryuchkov ◽  
I. L. Gonik
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Chemical Composition ◽  
Grain Growth ◽  
Base Metal ◽  
Welded Joints ◽  
Austenitic Steels ◽  
Welding Cycle ◽  
Thermal Welding ◽  
Positive Effect

The results of studies on the influence of the chemical composition on mechanical properties of the base metal and the metal of the near-seam zone of welded joints of ferrite-austenitic steels are presented. The positive effect of microalloying of steels with calcium and cerium on the resistance to embrittlement of the metal after exposure to the thermal welding cycle is shown. It is established that alloying ferrite-austenitic steels with molybdenum and vanadium reduces the tendency to grain growth during welding heating, and doping with nitrogen leads to the stabilization of the phase composition of steels under the influence of elevated welding and operating temperatures.

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