Influence of Weld Oxides on Ductility and Fracture Toughness of Electric Resistance Welded Joint

1994 ◽  
Vol 80 (4) ◽  
pp. 324-329
Author(s):  
Tetsuya TAGAWA ◽  
Syuuhei YAMAMOTO ◽  
Takashi MIYATA
2020 ◽  
Vol 35 (14) ◽  
pp. 1790-1802
Author(s):  
Yuan Gao ◽  
Chendong Shao ◽  
Haichao Cui ◽  
Ninshu Ma ◽  
Fenggui Lu

Abstract


2020 ◽  
Vol 52 (8) ◽  
pp. 1732-1741
Author(s):  
Xiangqing Li ◽  
Zhenyu Ding ◽  
Chang Liu ◽  
Shiyi Bao ◽  
Hao Qian ◽  
...  

2013 ◽  
Vol 791-793 ◽  
pp. 346-349
Author(s):  
Bo Lin He ◽  
Ying Xia Yu ◽  
Si Yong Lei ◽  
Li Xing Huo

It is important for the design engineer to realize that scatter and variability of materials properties are inevitable and must be dealt with appropriately. On occasion, data must be subjected to statistical treatments and probabilities determined. The fracture toughness of pipe steel has great effect on the safety of welded pressure pipe. The fracture toughness test of circumferential welded joint was carried out in this paper for X65 pressure pipe steel. The fracture toughness experimental results were analyzed by using computer program developed by ourselves. The distribution of weld fracture toughness of X65 pressure pipe steel which may accord with normal distribution, lognormal distribution or weibull distribution can be determined by calculating the results only one time. The program, which plays an important role in structure reliability analysis, can be used to determine the probability statistic distribution of the mechanical properties. The calculated results indicate that the weld fracture toughness of the X65 pressure pipe steel can either accord with normal distribution, lognormal distribution or weibull distribution, but the optimum fitting distribution of the fracture toughness is weibull distribution.


Author(s):  
Satoshi Igi ◽  
Takahiro Kubo ◽  
Masayoshi Kurihara ◽  
Fumiyoshi Minami

Recently the Weibull stress is used as a fracture driving force parameter in fracture assessment. The Weibull stress is derived from a statistical analysis of local instability of micro cracks leading to brittle fracture initiation. The critical Weibull stress is expected to be a critical parameter independent of the geometrical condition of specimens. Fracture toughness test using 3-point bending and tensile tests of welded joint specimens with geometrical discontinuity were conducted in order to study the applicability of fracture assessment procedure based on Weibull stress criterion. Steel plates prepared for this study had tensile strength of 490 MPa for structural use. Two kinds of welded joint specimens, “one-bead welded joint” and “multi-pass welded joint” were prepared for fracture toughness test by using gas metal are welding. In tensile test specimen, corner flaws were introduced at the geometrical discontinuity part at where stress concentration is existed. Three dimensional elastoplastic finite element analyses were also carried out using the welded joint specimen models in order to calculate the Weibull stress. The critical loads for brittle fracture predicted by the Weibull stress criterion from CTOD test results of one-bead and multi-pass welded joint specimens show fairly good agreement with experimental results of welded joint specimens with geometrical discontinuity.


Author(s):  
Masahito Mochizuki ◽  
Masao Toyoda ◽  
Masayuki Inuzuka ◽  
Hidehito Nishida

Mechanical properties and fracture toughness in friction stir welded joint of vessels of structural aluminum alloy type A5083-O are investigated. Welded joint from 25 mm-thick plate is fabricated by one-side one-pass friction stir. Charpy impact energy and critical crack-tip opening displacement (CTOD) in friction stir weld are much higher than those of base metal or heat-affected zone, whereas mechanical properties such as stress-strain curve and Vickers hardness do not have a conspicuous difference. Effects of microstructure on crack initiation and propagation are studied in order to clarify the difference of fracture toughness between stir zone and base metal. Both tensile test and bending test show that the fine-grained microstructure in stir zone induces to increase ductile crack initiation and propagation resistance by analyzing fracture resistance curves and diameter of dimples in fracture surface. It is found that high fracture toughness value in stir zone is affected fine-grained microstructure by friction stirring.


2009 ◽  
Vol 23 (3) ◽  
pp. 166-172 ◽  
Author(s):  
Walter Jesus Paucar Casas ◽  
Sérgio Luiz Henke ◽  
Nilceu Novicki

2015 ◽  
Vol 638 ◽  
pp. 240-250 ◽  
Author(s):  
Qian Guo ◽  
Fenggui Lu ◽  
Xia Liu ◽  
Renjie Yang ◽  
Haichao Cui ◽  
...  

Author(s):  
Akira Shimamoto ◽  
Keitaro Yamashita ◽  
Hirofumi Inoue ◽  
Sung-mo Yang ◽  
Masahiro Iwata ◽  
...  

Destructive tests are generally applied for evaluating fixed strength of spot welding nuggets on zinc plating steel, which is swidely used as the primary automobile structural material. Destructive tests, however, are expensive and time consuming. This paper discusses a non-destructive method for evaluating of welded joints fixed strength by utilizing surface electric resistance. A nugget tester has developed by authors for this purpose. The non-destructive method focuses on surface electric resistance decreasing rate; α, and effect of the corona bond. Nugget diameter is estimated by RQuota calculated from variation of resistance and constant representing the area of the corona bond. Since maximum tensile strength is correlated with the nugget diameter, it is inferred from the estimated nugget diameter.


2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Bin Wang ◽  
Hongxia Lan ◽  
Bobo Lei

The fracture toughness of the weld and heat-affected zone (HAZ) of the L360QS/N08825 composite pipe welded joint was evaluated by a crack tip opening displacement (CTOD) test. The fracture morphology, microstructure, and inclusion near fracture zones were observed by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive spectroscopy (EDS). The grain size and grain orientation of the crack propagation zone in the weld were investigated by electron back-scattered diffraction (EBSD). The results revealed that the average CTOD values of the weld and HAZ samples were relatively high, and a greater dispersion of CTOD values of the HAZ samples is due to the pop-in phenomenon in the P–V curve. The fracture surfaces of the weld and HAZ samples showed the characteristics of ductile fracture to a certain extent, whereas the fracture of the CTOD sample with the pop-in phenomenon exhibited a quasicleavage feature. High-density dislocation and a large number of inclusions were observed in the near fracture zone of the weld and HAZ samples. The stress concentration, caused by hindering the dislocation slip, was the main reason for microcrack formation. The existence of large-size grains and large-scale small-angle grain boundary in the weld implies that the cracks propagate toward the weld.


1995 ◽  
Vol 61 (588) ◽  
pp. 1707-1712 ◽  
Author(s):  
Keiichi Hasegawa ◽  
Kiyoshi Ando ◽  
Shouji Kitade ◽  
Mitsumasa Sakamoto ◽  
Yukio Fukushima ◽  
...  

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