scholarly journals Investigation of penetrator defect formation during high frequency induction welding in pipeline steels

2021 ◽  
Vol 349 ◽  
pp. 04002
Author(s):  
Christos Sofras ◽  
Marianthi Bouzouni ◽  
Nikolaos Voudouris ◽  
Spyros Papaefthymiou
Keyword(s):  
Chemical Composition ◽  
High Frequency ◽  
Defect Formation ◽  
Welding Process ◽  
High Strength ◽  
Chemical Compositions ◽  
Oxide Formation ◽  
Pipeline Steels ◽  
The Impact ◽  
High Frequency Induction

The aim of this study is to investigate the formation of oxide defects known as penetrators during high frequency induction welding process of high strength low alloy pipeline steels and to correlate their formation with the steel chemical composition. Penetrators formed during the welding process can be detrimental for the impact properties of the weld seam. For this purpose, three different samples, with different chemical compositions, were intentionally produced with penetrator-type oxides and investigated. In order to characterize the oxide defect and correlate their formation with the chemical composition of the steel, optical microscopy and scanning electron microscopy paired with energy dispersive spectroscopy were employed. In addition, thermodynamic calculations were performed in order to examine whether the chemical composition of pipeline steels is prone to oxide formation. The results showed that oxides with pancake type morphology were found alongside the fusion zone of the samples. They mainly consisted of manganese and silicon. First findings on the the Mn/Si ratio showed that the lower ratio is less susceptible to oxide formation.

Investigation on the effects of the joint type on the driven out bead in the welded pipes produced by high-frequency induction welding

2020 ◽  
pp. 146442072097343
Author(s):  
M Ghaffarpour ◽  
D Akbari ◽  
H Moslemi Naeini
Keyword(s):  
Mechanical Properties ◽  
Weld Joint ◽  
High Frequency ◽  
Weld Zone ◽  
Welding Process ◽  
Solid Material ◽  
Outer Diameter ◽  
Metallurgical Properties ◽  
Semi Solid ◽  
High Frequency Induction

In this paper, the effects of the joint type on the driven-out bead of the roll-formed pipes, welded by high-frequency induction welding process are studied. The main goal is to predict and reduce the volume of the bead driven out in the weld seam. Moreover, it aims to move the semi-solid bead during welding to the outer diameter of the pipe. This study has two prior aims: to produce a defect-free joint and to improve the mechanical and metallurgical properties. In order to optimize the weld joint, various joint types have been investigated by experimental tests and simulation. Lastly, destructive tests were used to determine if the desired mechanical properties of the weld joint were obtained. The metallurgical properties and the derivation of the semi-solid material in the weld zone have both been investigated in terms of microstructure. According to the results, the proper joint type improves the mechanical properties by 5% and reduces the volume of the weld bead about 45%.

Austenite Decomposition Kinetics in Laser-Hybrid Welding of Steel of Strength Class K52

2019 ◽  
Vol 946 ◽  
pp. 950-955 ◽  
Author(s):  
A.I. Romantsov ◽  
M.A. Fedorov ◽  
D.G. Lodkov
Keyword(s):  
Welded Joints ◽  
Strength Class ◽  
Defect Formation ◽  
Welding Process ◽  
Decomposition Kinetics ◽  
Hybrid Welding ◽  
Austenite Decomposition ◽  
Laser Hybrid Welding ◽  
Laser Hybrid ◽  
The Impact

A modern technology for joining materials welding is commonly used in various industries. It is a process of interaction of thermal, mechanical and metallurgical properties and behaviors. Complex phenomena, such as solidification, microstructural changes and defect formation, have a great impact on the quality of welded joints. This article presents the results of studying the features of the austenite decomposition kinetics in the application of laser-hybrid welding technology, in a combination with multi-arc automatic submerged arc welding. The cooling rates are determined, affecting the change in properties of HAZ of welded joints on pipe steel of strength class K52. Using the dilatometric method, studies were conducted and thermo-kinetic and structural diagrams were constructed. Analysis of diagrams and microstructures showed that, as a result of the impact of the laser-hybrid welding process in the area of HAZ, the decomposition of austenite occurs mainly in the martensitic zone, followed by the formation of a bainite-perlite structure, due to recrystallization from the heat generated by the facing seams.

Mechanical Properties of Vanadium Microalloyed High-Strength ASTM A694 Forgings

2017 ◽  
Author(s):  
K. C. Baker ◽  
R. M. Thompson ◽  
T. C. Gorrell
Keyword(s):  
Chemical Composition ◽  
Oil And Gas ◽  
Charpy Impact ◽  
High Strength ◽  
Oil And Gas Industry ◽  
Heat Treating ◽  
Manganese Steel ◽  
Material Test ◽  
Shear Area ◽  
The Impact

Recent upstream oil and gas industry experience has raised attention to substandard properties with high strength carbon steel forgings manufactured to the requirements of ASTM A694 and MSS-SP-44. As part of an internal investigation into quality of commodity pipeline flanges, three flanges certified as ASTM A694 grade F60 to F70, were purchased off-the-shelf from three different manufacturers for microstructural and mechanical property investigation. All three flanges were supplied with material test certificates indicating acceptable material properties. Tensile and Charpy impact specimens were extracted from various locations and orientations in each flange. All three flanges failed to meet yield strength requirements for the specified grade. The impact energy and shear area values were well below those reported on the material test certificates. The discrepancy between the sacrificial testing results and the material test certificates is attributed to the use of separately forged test blocks for quality testing instead of integral prolongations or a sacrificial production part, which is permitted by ASTM A694 and MSS-SP-44. Further investigation was made into the chemical composition and heat treating practices. The chemical composition can be characterized as high strength, low alloy steel (HSLA) by virtue of 0.05–0.08 wt. pct. vanadium added to a carbon-manganese steel with CE(IIW) ranging from 0.43 to 0.45. Advanced microscopy showed that the morphology of the vanadium precipitates was inadequate as a strengthener and deleterious to Charpy impact properties for the size of the flanges and the heat treatment practices applied.

scholarly journals Two-time Calibration at Both Ends for Sulfur Measurement by Using High Frequency Induction Infrared Absorption Method

2022 ◽  
Vol 2160 (1) ◽  
pp. 012005
Author(s):  
Jianhuan Wei
Keyword(s):  
Infrared Absorption ◽  
High Frequency ◽  
Measurement Method ◽  
Absorption Method ◽  
High Temperature Alloy ◽  
Accuracy And Precision ◽  
Time Calibration ◽  
Low Sulfur ◽  
The Impact ◽  
High Frequency Induction

Abstract High frequency induction heating infrared absorption method is a relative measurement method, and it requires calibrating the analyzer during the measurement process. Usually, one-time calibration on an analyzer is made for high sulfur value by using standard substances. The method proposed by this paper calibrates carbon-sulfur analyzers with a method of two-time calibration at both ends, which eliminates the impact of sulfur blank and thus improves the accuracy and precision of ultra-low sulfur measurement. The method extents the lower limit of measurement of sulfur in high temperature alloy, to 0.00005%, namely, 0.5ppm.

scholarly journals Influence of the Welding Process on the Mechanical Characteristics and Fracture of the S700MC High Strength Steel under Various Types of Loading

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5249
Author(s):  
Tadeusz Szymczak ◽  
Katarzyna Makowska ◽  
Zbigniew L. Kowalewski
Keyword(s):  
Fracture Toughness ◽  
Welding Process ◽  
High Strength ◽  
Mechanical Tests ◽  
Parent Material ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Joint Stress ◽  
Characteristic Features ◽  
The Impact

This paper focuses on the mechanical properties analysis of the high strength S700MC steel applied in welding joints. The research comprised mechanical tests for checking what the changes of tensile characteristics, mechanical parameters, resistance to impact, and fracture toughness look like in selected regions of the welding joint. Stress-strain curves have shown significant differences in the tensile characteristic shape and the values of Young’s modulus, yield stress, ultimate tensile strength, and ductility due to the welding process applied. In the case of Charpy tests, the courses of the accumulated energy, force, deflection, and project velocity are presented, indicating the maximum value of absorbed energy, the same level of force during the first contact of the projectile with the specimens, and the significant variation of the velocity for the impact energy ranging from 50 J up to 300 J. On the basis of the fracture toughness tests, the distributions of the CTOD (Crack Tip Opening Displacement) values are presented for the parent material, HAZ (Heat Affected Zone) and weld. Moreover, the characteristic features of the fatigue pre-crack, transient and crack propagation zones are identified and discussed.

Development of High Strength Center-pillar by High Frequency Induction Heating

2008 ◽  
Vol 32 (6) ◽  
pp. 533-539 ◽  
Author(s):  
Jin-Hyug Son ◽  
Young-Jin Yum ◽  
Won-Hyuck Kim ◽  
Jung-Bok Hwang ◽  
Sun-Ung Kim ◽  
...  
Keyword(s):  
Induction Heating ◽  
High Frequency ◽  
High Strength ◽  
High Frequency Induction

Mechanical Behaviour of Intercritically Reheated Coarse-Grained Heat Affected Zone in High Strength Line Pipe Steels

2018 ◽  
Author(s):  
Madhumanti Mandal ◽  
Warren J. Poole ◽  
Thomas Garcin ◽  
Matthias Militzer ◽  
Laurie Collins
Keyword(s):  
Impact Toughness ◽  
Heat Affected Zone ◽  
Welding Process ◽  
Charpy Impact ◽  
High Strength ◽  
Coarse Grained ◽  
Fracture Mechanisms ◽  
Line Pipe ◽  
Secondary Cracks ◽  
The Impact

Multipass welding of high strength steels used for fabrication and joining of transmission pipelines presents a number of metallurgical challenges. A key concern is both the strength and toughness of the heat affected zone (HAZ) adjacent to both seam and girth welds. In this work, a systematic study has been conducted on regions of the heat affected zone in the base metal where the first welding pass produces a thermal excursion which results in a coarse-grained heat affected zone (CGHAZ). The subsequent weld pass involves intercritical annealing of this region, i.e. a microstructure associated with intercritically reheated coarse grain heat affected zone (ICCGHAZ). The small ICCGHAZ region is often identified as being particularly susceptible to crack initiation. This work was undertaken to understand microstructure development in this zone and how the ICCGHAZ may affect the overall performance of the HAZ. Gleeble thermomechanical simulations have been conducted to produce bulk samples representative of different welding scenarios. Charpy impact tests and tensile tests have been performed over a range of temperatures. It was found that when a continuous necklace of martensite-austenite islands form on the prior austenite grain boundaries (i.e. for a M/A fraction of ≈10%), the Charpy impact toughness energy is dramatically decreased and the ductile brittle transition temperature is significantly raised. Detailed studies on the secondary cracks have been conducted to examine the fracture mechanisms in the different microstructures. The results show that the lower bainite microstructures obtained after the 1st thermal treatment, representative of CGHAZ have excellent impact properties. The impact toughness of the microstructures typical of ICCGHAZ is strongly dependent on the composition as well as morphology and spatial distribution of the resulting martensite-austenite (M/A) islands transformed from inter-critically formed austenite. This zone can play a significant role in fracture initiation and thus needs to be considered in alloy and welding process designs.

Manufacturing of 25mm Heavy-Wall Linepipe Using the High Frequency Induction (HFI) Welding Technique: A Challenge for a Pipe Manufacturer

2010 ◽  
Author(s):  
Athanasios S. Tazedakis ◽  
Nikolaos G. Voudouris ◽  
Mike Musslewhite
Keyword(s):  
Weld Seam ◽  
Hsla Steel ◽  
Welding Process ◽  
High Strength ◽  
Thick Wall ◽  
Hot Strip ◽  
Hot Rolled ◽  
Inspection Techniques ◽  
Welding Technique ◽  
High Frequency Induction

The current thickness limit of the HFI technique is about 20,6mm for grades up to X80. It is mainly governed by the necessary forming load, the coil edge formability and above all the optimisation of the power/heat input requirements on the weld seam area. The availability of hot rolled coils in thicknesses up to 25mm has made possible the exploitation of the HFI limits to such thicknesses. Following the successful industrial HFI welding production of 609,6mm (24″) × 25mm thick wall pipes at the CPW-Thisvi mill, the current paper deals with the development of the process regarding forming, welding, process automation and NDE inspection techniques for thicknesses up to 25mm. The latter made possible the broadening of the HFI process limits, currently for grades up to X60. Details of the technology used are described along with the investigation of the influence of welding and post-weld heat treatment (PWHT) cycles on the microstructure of the welding zone (WZ) and heat affected zone (HAZ) of the hot-strip micro-alloyed high strength low alloyed (HSLA) steel chosen. Mechanical testing of the pipe body and weld seam was used to characterise their performance. The dimensional tolerances of the pipe products are also described. Results of the study showed properties which were uniform and satisfied API 5L requirements. The above research demonstrates that the HFI technique has a clear potential to provide the energy market with lower cost-options for the construction of heavy wall pipes.

Investigations Into the Microstructure–Toughness Relation in High Frequency Induction Welded Pipes

2010 ◽  
Author(s):  
O¨. E. Gu¨ngo¨r ◽  
P. Yan ◽  
P. Thibaux ◽  
M. Liebeherr ◽  
H. K. D. H. Bhadeshia ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
High Frequency ◽  
Welding Process ◽  
Post Weld Heat Treatment ◽  
Weld Microstructure ◽  
Weld Properties ◽  
Linepipe Steel ◽  
High Frequency Induction ◽  
Weld Heat

In the present paper, investigations performed on ArcelorMittal X65 linepipe steel in order to understand the effects of high frequency induction (HFI) welding process and in-line post-weld heat treatment on weld properties are described. The factors that potentially can affect weld toughness, such as microstructure, grain size, precipitates, hardness, inclusions, and texture, are evaluated and discussed systematically in order to correlate weld microstructure with toughness of the HFI welded pipes.

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