Microstructural, mechanical and nondestructive characterization of X60 grade steel pipes welded by different processes (original) (raw)
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The International Conference on Materials Science, Mechanical and Automotive Engineerings and Technology in Cappadocia (IMSMATEC 2019), 2019
In this work, various welding procedures including shielded metal arc welding and/or tungsten inert gas welding were applied to 24'' diameter API 5L X60 steel pipes used in natural gas and crude oil pipelines. The welding plans were considered to be 4 passes in total which were root pass, hot pass, fill pass and cap pass. The root and hot passes were made as one bead, whereas the fill and cap passes were implemented as two and three beads, respectively. After the welding applications, the welded samples were subjected to tensile, hardness and notch impact tests. Moreover, the macro and microstructural analyses were carried out to examine heat effected zone and grain morphology.
Examination Of Mechanical Properties And Weld Zone Of X70 Pipe Steel After Welding
International Journal of Scientific & Technology Research, 2017
The demand for large diameter pipes in terms of their strength and toughness properties is increasing day by day. The quality and mechanical strength values of the steels, used in new gas pipeline projects, are gradually increasing. Today, high strength steels are used instead of the steels with low yield values. In this study, the micro-structure mechanical properties of the high strength X70 steel, used in the Trans Anatolian Gas Pipeline Project (TANAP), were investigated before and after the welding process and the weld zone was examined. The submerger arc welding process has been employed for the weld process. While the mechanical properties were determined by tensile, notched bend impact, bend and hardness measurements, the microstructures were examined by using optical microscope and scanning electron microscope (SEM). The radiographic and ultrasonic methods were employed in the non-destructive test of the weld zone.
MATEC Web of Conferences, 2019
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 in...
INVESTIGATION OF THE MECHANICAL AND MICROSTRUCTURAL PROPERTIES OF WELDED API X70 PIPELINE STEEL
The mechanical properties of pipelines particularly those in marine environments are influenced by corrosion activity of seawater throughout their service lives. The degree to which these properties are influenced in seawater compared to those exposed to air needs to be better understood. In this study, the chemical composition of API X70 pipeline steel plate, microstructure and mechanical properties of the welded joints of same steel plates exposed to ambient air and seawater respectively were investigated. It was found that the base metal consisted of manganese (0.51wt% Mn), low carbon content (0.051 wt% C) and small quantities of alloying elements such as vanadium (0.021wt% V), molybdenum (0.118 wt% Mo), chromium (0.240 wt% Cr), copper (0.002 wt% Cu), and a carbon equivalent (CE IIW) of 0.38. Scanning Electron Microscope (SEM) showed that the microstructure of base metal sample has large grains formed in packets which have certain crystallographic orientation but contain submicron grains arranged in a chaotic interlocking manner. The tensile tests performed using a UNITED type universal testing machine confirmed that the yield strength of the base metal was 573.045MPa which conforms to API standard for X70 steel pipe. The manual metal arc (MMA) welding technique was applied to produce the welded joints. For the welded joints exposed to ambient air at room temperature, the yield strength was 680.624MPa while the compressive strength was 1500.2MPa, and the impact energy at-10°C was 112.68J. Air tests referred to tests conducted in the laboratory at room temperature. For the welded joints exposed to seawater for 12 weeks, the yield strength was 609.154MPa while the compressive strength was 1219.34MPa, and the impact energy at-10°C was 61.48J. The above results for air and seawater exposures were used to determine the environmental reduction factors of the two environments. Hardness tests conducted using Vickers hardness tester revealed variations in hardness across the base metal, the HAZ and the weld, with the weld having the highest average Vicker's hardness value (223.8HV) followed by the base metal (217.3HV) and the HAZ had the least (214.5HV)
2021
In this work, the influence of welding parameters on macrostructure, microstructure and mechanical properties in Gas Tungsten Arc Welding (GTAW) orbital pipe welding was investigated. The aim of this study was to evaluate the effect of GTAW orbital pipe welding parameters on macrostructure, microstructure and tensile strength. This experiment using A36 mild steel pipe material with a thickness of 0.6 mm and an outer diameter of 114.3 mm. The joining method used is the V-groove join without gaps with the ER70-S 6 wire feeder. Welding results were analyzed in macro and micro graphs, as well as analysis of tensile strength. Macro-graphic analyses revealed the depth of weld penetration that occurs as well as the boundaries of each welding area. The micro-graphic analysis shows structural changes that occur in the welding area. Welding parameters with a welding current of 170 A, a welding speed of 0.9 mm/s and a welding position of 0° have a Ultimate Tensile Strength (UTS) increase of 11...
Influence of Heat Treatments on the Microstructure of Welded Api X70 Pipeline Steel
2017
Welding is one of the most important technological processes used in many branches of industry such us industrial engineering, shipbuilding, pipeline fabrication among others. Generally, welding is the preferred joining method and most common steel are weldable. This investigation is a contribution to some scientific works which have been done on welding of low carbon steel. This work, presents some heat treatments were used to alter the microstructure of base metal (BM), heat affected zone (HAZ) and weld metal (WM) in the welded pipe steel of grade API X70. It presents the microstructures obtained after three heat treatments at 200°C, 400°C and 600°C for 30 min. Scanning electron microscopy and X-ray diffraction have been used as characterization techniques to observe the WM microstructures, in addition the Vickers hardness test are also achieved. The results revealed that the isothermal heat treatment caused grain growth and coarsening reactions in the weld zone and the hardness o...
Analysis of Welding Procedure Specifications for steel line pipe material
SINERGI
This study proposes the welding process steel line pipe material of API5L Grade X52 diameter Ø8 inch SCH80 type, subjected to the good quality of the product by following the Welding Procedure Specifications (WPS). The purpose of welding using WPS is to ensure that the welding process follows the correct stages because the steps are proper. The weld results will be free from defects and safe for line pipes. In order to confirm the WPS quality, the characterisations of macrostructure, microstructure, and mechanical properties were analysed. The welding process results by following the procedure specifications, from macrostructure shown no porosity, and sample without following the welding procedure specifications shown porosity at weld metal position. The tensile test sample following the welding procedure specifications showed high strength and ductility compared with the samples without welding procedure specifications. This phenomenon occurs due to the grain size of the martensiti...
2013
This report is presents about the investigation towards mechanical properties property of dissimilar welding by using different welding technique and processes. The objective of this research is investigate the weld joint quality of aluminium AA6061 and galvanized iron with different types of joining those are butt and lap joint and with different of welding processes, namely Metal Inert Gas (MIG) and Tungsten Inert Gas (TIG). The experiments carried out along this research such as non-destructive test (NDT), Vickers hardness test, tensile test and microstructure optical analysis. Based on the result of experiment, there are a few defects on weld appearances such as porosity, crack, and incomplete penetration. Butt joint of TIG welding (TBAG) shows a better weld appearance compared to other groups. Microstructure analysis showed that joint of TBAG has thinner brittle intermetallic compound layer (IMC) than the other group which shows thicker IMC, indicating a weaker joint. Based on ...
Materials Today: Proceedings, 2020
Joining of materials with the help of submerged arc welding machine is widely used in the concerned industries. The quality of the weld is identified by several welding output parameters like weld width, reinforcement height, depth of penetration, hardness, impact strength and tensile strength etc. The input welding parameters on which outputs depend are welding current, voltage, feed rate, speed of welding, electrode extension, diameter of electrode and electrode angle etc. All the researchers try to optimize these parameters according to the concerned requirement. In this review paper it was tried to consider different research papers containing the research and analysis made on input output parameters of submerged arc welding process. This paper also focused on analysis of some research papers containing heat input rate, cooling rate of weld, micro structure of weld and heat affected zone and their effect on the performance of the joint. Total 28 research papers were selected for our consideration after a thorough investigation of several such papers. After the analysis of the research papers the future scope of research was also suggested.
Advances in Materials Science
Welding is an indispensable manufacturing process in the shipbuilding industry. The fierce competition involved often necessitates a cost-effective and reliable welding method. In this study, the weldabilities, microstructures and some mechanical properties of ASTM A131 (Grade A) steel joints fabrication by submerged arc welding (SAW), metal active gas (MAG) welding and plasma arc welding (PAW) have been investigated. The microstructures of the welds were examined by optical microscopy. The mechanical properties of the joints were determined by microhardness measurements, tensile and impact tests. The results showed that tensile strength of the joints reached a tensile strength of up to 462 MPa. The locations of the fractures were always adjacent to the base metal. The Charpy impact energy of the weld metal reached a value of 72.5 J, which was 25 % higher than that of the base metal at 57.7 J. A relatively high hardness of 221 HV was obtained in the PAW method compared to 179 HV in ...