scholarly journals Properties of Welded Joints on Superheater Coils Made from New Generation High Alloy Martensitic Steels Connected to Austenitic Creep-Resisting Steels and Supper Alloy Grades, for Supercritical Parameters

2011 ◽  
Vol 278 ◽  
pp. 466-471 ◽  
Author(s):  
Jerzy Pasternak ◽  
Janusz Dobrzanski
Keyword(s):  
Welded Joints ◽  
Base Material ◽  
Implementation Process ◽  
Steam Superheater ◽  
Austenitic Steels ◽  
Martensitic Steels ◽  
Operation Process ◽  
Supercritical Parameters ◽  
Steel Grades ◽  
Creep Resistant Steels

The continuously developing power generation sector, including boilers with supercritical parameters, requires applications of new creep-resistant steel grades for construction of boilers steam superheater components. Therefore, this paper contains selected information, results of the research and implementation process including: - evaluation, comparison of requested properties of base material and welded joints, such as tensile strength, impact strength and technological properties, - destructive examinations with evaluation of welded joints and HAZ structure and hardness distribution, - influence of manufacturing process in large boilermaker conditions and after simulated operation. A new creep-resistant steels to be used, in order to comply with the operational requirements, as to assure the appropriate reliability and safety of the boiler equipment in operation process. This document presents a simplified analysis of martensitic steels from group 9-12% Cr (T91, T92, HCM12A, VM12) and austenitic steels Cr-Ni (TP347FG, SUPER 304H, HR3C), having the chemical composition as presented in tables 1 and 2, which are to be applied for steam superheater components.

Reliability and Safety of the Power Equipment in Respect of Properties Evaluation of Welded Joints Made From New Generation Creep-Resisting Steels

2009 ◽  
Author(s):  
Janusz Dobrzanski ◽  
Jerzy Pasternak
Keyword(s):  
Welded Joints ◽  
Technology Implementation ◽  
Base Material ◽  
Implementation Process ◽  
Steam Superheater ◽  
Operating Process ◽  
Creep Resistant Steels ◽  
Corrosion Mechanisms ◽  
Working Parameters ◽  
New Generation

The modernisation of power generation sector has involved the construction of new power units, having supercritical parameters e.g. 580/ 600°C with 280bar, and calculated efficiency of approx. 43%. The new boilers are supercritical ones of capacities 440MW and 840MW. Their investors expect that new creep-resistant steels to be used in order to comply with the operational requirements, as well as to assure the appropriate reliability and safety of the boiler equipment in operation. Authors describe a co-operating process has been made with RAFAKO S.A. the Institute for Ferrous Metallurgy in Gliwice, the Institute of Welding and the Silesian Technical University in Katowice, for several years now, initiating research and development programmes. This paper contains selected information, test results and their evaluation before implementation of the new creep-resistant steels, including evaluation of: - working parameters and temperature conditions of main boiler components, which influence reliability and safety procedures, - base material, welded joints and HAZ structure by means of LM and SEM methods in the welding technology implementation process, - the requested level of mechanical properties, including corrosion mechanisms, - corrosion and creep-resistance results, - loss of service life for selected evaporator and steam superheater components, as crucial elements in evaluation of reliability and safety of boiler equipment.

scholarly journals Crash Response of Laser-Welded Energy Absorbers Made of Docol 1000DP and Docol 1200M Steels

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2808
Author(s):  
Paweł Prochenka ◽  
Jacek Janiszewski ◽  
Michał Kucewicz
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Welded Joints ◽  
Impact Loading ◽  
High Strain ◽  
Mechanical Energy ◽  
Base Material ◽  
Strain Rates ◽  
Loading Conditions ◽  
Steel Grades

The crushing response of a laser-welded square tube absorber made of two commercial steel grades, Docol 1000DP and Docol 1200M, is presented in the paper. Crush experiments are performed at two different loading conditions, namely, quasi-static loading at 0.5 mm/s deformation speed and impact loading at 25–28 m/s. A new approach has been proposed to study the square tube absorber under impact loading using a direct impact Hopkinson (DIH) method. To characterize the mechanical properties of the tested steels, tensile quasi-static and high strain rate testing are also performed with the use of specimens with a 7 mm gauge length. The applied strain rates are 10−3, 100, and above 103 s−1. The laser-welded joints are also characterized by microhardness test involving the base material, heat-affected zone, and fusion zone. The crashworthiness of model square tube absorbers is estimated based on the following parameters: absorbed energy, mean force, crushing force efficiency factor, and specific energy absorbed. It has been found that the square tube absorbers made of Docol 1200M steel show a higher potential in mechanical energy absorption capacity than Docol 1000DP absorber. Moreover, crushing tests prove that laser-welded joints in 0.6 mm sheets made of Docol 1000DP and Docol 1200M steels reveal high cracking toughness. In turn, strength testing at different strain rates confirms the higher strain rate sensitivity of Docol 1000DP steel than in the case of Docol 1200M steel as well as an increase in the high ductility properties of both steel grades under the high strain rate loading conditions.

scholarly journals Microstructural and Mechanical Characterization of Electron Beam Welded Joints of High Strength S960QL and Weldox 1300 Steel Grades

2017 ◽  
Vol 62 (2) ◽  
pp. 627-634 ◽  
Author(s):  
S. Błacha ◽  
M.S. Węglowski ◽  
S. Dymek ◽  
M. Kopyściański
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Welded Joints ◽  
Base Material ◽  
Steel Grade ◽  
Fusion Line ◽  
Bending Test ◽  
Metallographic Examination ◽  
Steel Grades ◽  
The Impact

Abstract The paper shows the results of metallographic examination and mechanical properties of electron beam welded joints of quenched and tempered S960QL and Weldox 1300 steel grades. The aim of this study was to examine the feasibility of producing good quality electron beam welded joints without filler material. Metallographic examination revealed that the concentrated electron beam significantly affects the changes of microstructure in the weld and the adjacent heat affected zone (HAZ) in both steel grades. The microstructure of the welded joints is not homogeneous. The four zones, depending on the distance from the weld face, can be distinguished. Basically, the microstructure of the weld consists of a mixture of martensite and bainite. However, the microstructure of HAZ depends on the distance from the fusion line. It is composed of martensite near the fusion line and a mixture of bainite and ferrite in the vicinity of the base material. Significant differences in mechanical properties of the welded joints were observed. For a butt welded joint of the S960QL steel grade the strength is at the level of the strength of the base material (Rm = 1074 MPa). During the bending test the required angle of 180° was achieved. The impact strength at −40°C was 71,7 J/cm2. In the case of the Weldox 1300 steel grade butt welded joints exhibit high mechanical properties (Rm = 1470 MPa), however, the plastic properties are on the lower level than for the base material.

scholarly journals Microstructure and Mechanical Properties of Modern 11%Cr Heat-Resistant Steel Weld Joints

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3430
Author(s):  
Grzegorz Golański ◽  
Jacek Słania ◽  
Marek Sroka ◽  
Paweł Wieczorek ◽  
Michał Urzynicok ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Welded Joints ◽  
Martensitic Steel ◽  
Base Material ◽  
Hardness Measurement ◽  
Power Industry ◽  
Strength Properties ◽  
Typical Structure ◽  
Δ Ferrite ◽  
The Impact

In addition to good high-temperature creep resistance and adequate heat resistance, steels for the power industry must have, among other things, good weldability. Weldability of such steels is one of the criteria determining whether or not the material is suitable for applications in the power industry. Therefore, when materials such as martensitic steel Thor 115 (T115) are introduced into the modern power industry, the quality and properties of welded joints must be assessed. The paper presents the results of metallographic and mechanical investigations of T115 martensitic steel welded joints. The analysis was carried out on joints welded with two filler metals: WCrMo91 (No. 1) and EPRI P87 (No. 2). The scope of the investigations included: microstructural investigations carried out using optical, scanning and transmission electron microscopy and mechanical testing, i.e., Vickers microhardness and hardness measurement, static tensile test and impact test. The macro- and microstructural investigations revealed correct structure of the weld, without welding imperfections. The microstructural investigations of joint No. 1 revealed a typical structure of this type of joint, i.e., the martensitic structure with numerous precipitates, while in joint No. 2, the so-called Nernst’s layers and δ-ferrite patches were observed in the weld fusion zone as well as the heat affected zone (HAZ). The mechanical properties of the test joints met the requirements for the base material. A slight influence of the δ-ferrite patch on the strength properties of joint No. 2 was observed, and its negative effect on the impact energy of HAZ was visible.

Mechanical Behaviour of Welded Joints Achieved by Multi-Wire Submerged Arc Welding

2017 ◽  
Vol 1143 ◽  
pp. 52-57
Author(s):  
Elena Scutelnicu ◽  
Carmen Catalina Rusu ◽  
Bogdan Georgescu ◽  
Octavian Mircea ◽  
Melat Bormambet
Keyword(s):  
Mechanical Behaviour ◽  
Welded Joints ◽  
Arc Welding ◽  
Base Material ◽  
High Strength ◽  
Submerged Arc Welding ◽  
Steel Plates ◽  
Wire Saw ◽  
Api 5L X70 Steel ◽  
Submerged Arc

The paper addresses the development of advanced welding technologies with two and three solid wires for joining of HSLA API-5l X70 (High-strength low-alloy) steel plates with thickness of 19.1 mm. The experiments were performed using a multi-wire Submerged Arc Welding (SAW) system that was developed for welding of steels with solid, tubular and cold wires, in different combinations. The main goal of the research was to assess the mechanical performances of the welded joints achieved by multi-wire SAW technology and then to compare them with the single wire variant, as reference system. The welded samples were firstly subjected to NDT control by examinations with liquid penetrant, magnetic particle, ultrasonic and gamma radiation, with the aim of detecting the specimens with flaws and afterwards to reconsider and redesign the corresponding Welding Procedure Specifications (WPS). The defect-free welded samples were subjected to tensile, Charpy V-notch impact and bending testing in order to analyse and report the mechanical behaviour of API-5l X70 steel during multi-wire SAW process. The experimental results were processed and comparatively discussed. The challenge of the investigation was to find the appropriate welding technology which responds simultaneously to the criteria of quality and productivity. Further research on metallurgical behaviour of the base material will be developed, in order to conclude the complete image of the SAW process effects and to understand how the multi-wire technologies affect the mechanical and metallurgical characteristics of the API-5L X70 steel used in pipelines fabrication.

The Properties of Welded Joints Made by 6082-T6 Aluminium Alloy and their Behaviour under Cyclic Loading Conditions

2015 ◽  
Vol 812 ◽  
pp. 375-380 ◽  
Author(s):  
D. Pósalaky ◽  
János Lukács
Keyword(s):  
Cyclic Loading ◽  
Automotive Industry ◽  
Welded Joints ◽  
Structural Engineering ◽  
Physical Simulation ◽  
Base Material ◽  
Point Of View ◽  
Test Results ◽  
Structural Elements ◽  
Effective Use

The magnitude of different aluminium alloys, especially the ones with higher strength, are increasing in the structural engineering, not just the usual applications (like the aerospace industry) but more likely in the automotive industry. There are more assumptions of the effective use of aluminium; we should highlight two important factors, the technological and the applicability criterions. The technological criterion is the joining of structural elements, frequently with welding thus the technological criterion ultimately is the weldability. The assumption of applicability comes from the loading capability of these structures, which is typically cyclic loading so the key issue from the point of view of applicability is the resistance to fatigue. This article represents physical simulation and fatigue test results both on the base material and on the welded joints.

scholarly journals Laser Welding Of Finned Tubes Made Of Austenitic Steels

2015 ◽  
Vol 60 (3) ◽  
pp. 1807-1812
Author(s):  
M. Stolecki ◽  
H. Bijok ◽  
Ł. Kowal ◽  
J. Adamiec
Keyword(s):  
Laser Welding ◽  
Austenitic Steel ◽  
Technological Process ◽  
Welded Joints ◽  
Austenitic Steels ◽  
Tube Production ◽  
High Quality ◽  
Manufacturing Costs ◽  
Finned Tubes

Abstract This paper describes the technology of welding of finned tubes made of the X5CrNi1810 (1.4301) austenitic steel, developed at Energoinstal SA, allowing one to get high quality joints that meet the requirements of the classification societies (PN-EN 15614), and at the same time to significantly reduce the manufacturing costs. The authors described an automatic technological line equipped with a Trumph disc laser and a tube production technological process. To assess the quality of the joints, one performed metallographic examinations, hardness measurements and a technological attempt to rupture the fin. Analysis of the results proved that the laser-welded finned tubes were performed correctly and that the welded joints had shown no imperfections.

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