Failure During Fabrication of an Armature Because of Lamellar Tearing

2019 ◽  
Keyword(s):  
Lamellar Tearing

Lamellar Tearing Observations Regarding the Application of European Standards in the Field of Welded Steel Constructions

2018 ◽  
Vol 69 (6) ◽  
pp. 1352-1354
Author(s):  
Anamaria Feier ◽  
Oana Roxana Chivu
Keyword(s):  
Bearing Capacity ◽  
Brittle Failure ◽  
Engineering Practice ◽  
Steel Bridge ◽  
Railway Bridge ◽  
Welded Steel ◽  
Direct Replacement ◽  
Lamellar Tearing ◽  
European Standards ◽  
Comprehensive Study

The problem of corrosion for old steel bridges in operation is often solved by direct replacement of elements or structure. Only a few studies have been done to determine the efforts influenced by corrosion in those elements. In general, it is considered that a corroded element has exceeded the bearing capacity and should be replaced, but if the corroded element is secondary it could be treated and kept. A factor in the rehabilitation of an old steel bridge in operation is the aspect of structure. If the structure is corroded, rehabilitation decision is taken is easier. Lamellar tearing describes the cracking that occurs beneath the weld and can be characterized as a brittle failure of steel, in the direction perpendicular to the plane of rolling. The paper presents a comprehensive study on lamellar tearing and summarizes some conclusions about the prevention of them. The conclusions will be exemplified in the case of a railway bridge, with a main truss girder. The paper presents also some observations regarding the stress analysis in fillet welds, resulting from the engineering practice.

State Analysis and Integrity of Welded Structures of the Upper Ring of the Turbine Runner Guide Vane Apparatus of Hydroelectric Generating Set A6 on Hydro Power Plant Djerdap 1

2013 ◽  
Vol 814 ◽  
pp. 7-18 ◽  
Author(s):  
Miodrag Arsić ◽  
Zoran Odanovic ◽  
Srdjan M. Bošnjak ◽  
Mladen Mladenović ◽  
Zoran Savić
Keyword(s):  
Welded Joints ◽  
Transverse Direction ◽  
Magnetic Particle ◽  
Guide Vane ◽  
Base Material ◽  
Metallic Inclusions ◽  
Crack Type ◽  
Turbine Runner ◽  
Lamellar Tearing ◽  
Non Destructive

During the refurbishment of the hydroelectric generating set A6 on HPP Djerdap 1, for the state analysis and assessment of the level and causes of degradation of the structure of the vertical Kaplan turbine runner guide vane apparatus non-destructive tests and inspections, as well as destructive tests of base material and welded joints, have been carried out after 40 years of service. Results of non-destructive tests performed on welded joints are presented in this paper (magnetic particle and ultrasonic inspection), as well as results of destructive tests of the base material and welded joints (testing of tensile properties, impact testing, metallographic analyses of the structure). A large number of crack type line indications were detected by magnetic particle inspections, while the occurrence of partial penetration in roots of welded joints was detected by ultrasonic inspections, as well as lamellar tearing of the base material. Tensile properties of tested samples taken in longitudinal and transverse direction fulfilled the requirements of the standard with certain deviations, which does not stand for samples taken in z-direction with significantly lower values of contraction of the cross-section than minimum prescribed values, which proves that base material is not resistant to the occurrence of lamellar cracks. Metallographic tests performed on specimens taken from the base material in longitudinal and transverse direction showed that the microstructure is stripe-shaped and ferrite-pearlite with non-metallic inclusions of oxide, sulphide, silicate and aluminate type, while metallographic tests performed on specimens taken from welded joints showed that their microstructure is stripe-shaped and ferrite-pearlite with non-metallic inclusions of oxide type. A large number of micro-and macro-cracks were detected in the microstructure as well. Experimental tests enabled the determination of the causes of occurrence of lamellar tearing in base material and crack type defects in welded joints, while analytical calculation that refers to the stress state enabled integrity of welded structure of the upper ring of the turbine runner guide vane apparatus.

Effect of Finish Rolling Process on Improvement of Lamellar Tearing Resistance of High-Rise Building Steel

2014 ◽  
Vol 1049-1050 ◽  
pp. 460-463
Author(s):  
Xin Cheng Li ◽  
Yu Ting Luo ◽  
Wei Xing Zhu ◽  
Xiao Li Wang ◽  
Yi Chen
Keyword(s):  
Rolling Process ◽  
Coiling Temperature ◽  
High Rise ◽  
High Rise Building ◽  
Finish Rolling ◽  
Phase Size ◽  
Lamellar Tearing ◽  
Average Size ◽  
Tearing Resistance ◽  
Precipitation Phase

A process of finish rolling was researched to enhance lamellar tearing resistant of the high-rise building steel EH36. Experimental results indicate that gain size decreased with the decrease of finish temperature. When the finishing temperature on 840/810/780/750°C respectively, microstructure is finest with the size of 11.4μm. Moreover, the size of TiC precipitation turned ideal as the coiling temperature decreased. When coiling temperature is 550°C, the average size of TiC precipitation is only 0.09μm, refined by 40% relative to the conventional process. The microstructure and precipitation phase size of test steel are both effectively controlled because of the improved process. Therefore, high-rise building steel EH36 is finally prepared, and the lamellar tearing resistance reaches up to 78.2%.

Microstructure and Properties of Q345E Lamellar Tearing Resistant Steel SAW Welding Joints

2014 ◽  
Vol 628 ◽  
pp. 48-52
Author(s):  
Xiao Qing Si ◽  
Hong Yun Zhao ◽  
Yi Xuan Zhao ◽  
Xiao Guo Song ◽  
Xiao Tian
Keyword(s):  
Resistant Steel ◽  
Microstructure And Properties ◽  
Dispersion Degree ◽  
Average Grain Size ◽  
Two Samples ◽  
Welding Thermal Cycle ◽  
Lamellar Tearing ◽  
Grains Refinement ◽  
Submerged Arc

The Q345E lamellar tearing resistant steel with 140mm thickness was welded by submerged arc welding (SAW). The microstructure and properties of the welded joints were investigated. Affected by the long-term welding thermal cycle, microstructure at different thickness has great differences. The hardness in the weld center is higher about 55 HV than the base metal. Due to the grains refinement of the microstructure at 1/2 thickness was more obvious, the microhardness of this zone has a more obvious dispersion degree. The average grain size of ferrite at the 1/4 thickness is about 10 μm, which resulted in two samples at this thickness obtain a higher tensile strength (496.568 MPa and 496.36 MPa). Moreover, part of the pearlite lamellar in the HAZ at 1/4 thickness had been fragmented and spheroidized.

scholarly journals On the Lamellar Tearing in Multirun Fillet Welds

1972 ◽  
Vol 41 (5) ◽  
pp. 578-586 ◽  
Author(s):  
Yasuhiro Nishio ◽  
Yoshihiro Yamamoto ◽  
Katsuya Kajimoto ◽  
Tsuneto Hirozane
Keyword(s):  
Fillet Welds ◽  
Lamellar Tearing

FINELINE and FINELINE DOUBLE-O FIVE ASTM A 633C PLATE

Alloy Digest ◽  
1988 ◽  
Vol 37 (3) ◽  
Keyword(s):  
Fracture Toughness ◽  
Physical Properties ◽  
Tensile Properties ◽  
Heat Treating ◽  
Steel Company ◽  
Product Lines ◽  
Wide Range ◽  
Steel Grades ◽  
Lamellar Tearing ◽  
Plate Steels

Abstract FINELINE and FINELINE DOUBLE-O FIVE plate steels are carbon and alloy steel grades produced to 0.010 and 0.005% maximum sulfur levels. They have improved through-thickness ductility with resultant reduction in the possibility of lamellar tearing in fabricated structures. While data herein refer specifically to ASTM A633C plate the improved product lines are applicable to a wide range of plate steels. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on forming, heat treating, machining, and joining. Filing Code: SA-429. Producer or source: Lukens Steel Company.

An Evaluation of Factors Significant to Lamellar Tearing

1982 ◽  
Vol 14 (1) ◽  
pp. 12
Author(s):  
E. J. Kaufmann ◽  
A. W. Pense ◽  
R. D. Stout
Keyword(s):  
Lamellar Tearing
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