Papers by Keyword: Structural Steel

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Authors: Kazutaka Mukoyama, Koushu Hanaki, Kenji Okada, Akiyoshi Sakaida, Atsushi Sugeta, Izuru Nishikawa, Akira Ueno, Tatsuo Sakai
Abstract: The aim of this study is to develop a statistical estimation method of S-N curve for iron and structural steels by using their static mechanical properties. In this study, firstly, the S-N data for pure iron and structural steels were extracted from "Database on fatigue strength of Metallic Materials" published by the Society of Materials Science, Japan (JSMS) and S-N curve regression model was applied based on the JSMS standard, "Standard Evaluation Method of Fatigue Reliability for Metallic Materials -Standard Regression Method of S-N Curve-". Secondly, correlations between regression parameters and static mechanical properties were investigated. As a result, the relationship between the regression parameters and static mechanical properties (e.g. fatigue limit E and static tensile strength σB) showed strong correlations, respectively. Using these correlations, it is revealed that S-N curve for iron and structural steels can be predicted easily from the static mechanical properties.
1639
Authors: Bum Yean Cho, Heung Youl Kim, Seung Cho Yang, Seung Un Chae
Abstract: This research is to show the microstructure of fracture parts of structural steels by welding at the high temperature. Discontinuity of mechanical and chemical property at HAZ of welding parts is the cause of decreasing structure safety. Therefore, this study was determined the effect of the welding of steels through a high temperature tensile tests and fracture portion of the microstructure. The results showed that does not cause destruction until temperature reached 600°C.
397
Authors: Harshad K.D.H. Bhadeshia
39
Authors: Can Dong Zhou, Jun Fei Fan, Hai Rong Le, Guo Chang Jiang, Jing Guo Zhang
Abstract: A structural steel, 35CrMoV steel, has been attempted firstly by explosive powder compaction followed by sintering (EPC-sintering). The nitrogen content of the steel was 0.15wt%, which was accordant with the definition of high nitrogen steel (HNS). The final density of the EPC-sintering steel was only about 6.9g/cm3, which indicated that the processing parameters must be modulated further. In the sample of this steel, some radial cracks were found around the center of the cross-section of the steel, resulting in no mechanical tests carrying out. Observing the majority of the rim region of the sample of this steel, the microstructures were very tight, suggesting that it was possible and successful to manufacture HNS through EPC-sintering. The characteristics of the EPC-sintering high nitrogen 35CrMoV steel were that the cementites in the pearlites were found to be extremely fine. There were many (Cr,Mo)23(C,N)6 carbonitrides precipitates in the matrix. Some precipitates were round and others were needle-like. Some were distributing orderly in matrix and crossing over the dislocations. The dislocation density in the EPC-sintering steel remained high.
265
Authors: Li Sha He, Nobusuke Hattori
Abstract: The present investigation attempts to evaluate the improvement of working by bolt on the fatigue limit of structural steel sheets with drilling a circular hole. The material used in this study is structural steel (JIS SM400A). And the specimens are identified to two types of the non-worked specimen and the worked specimen. The results obtained in this study can be summarized as follows: (1) The fatigue limit of worked specimens increases than that of non-worked specimen. Futhermore, there has a suitable value of the torque for improving the fatigue limits. (2) The reasons of enhancing the fatigue strength of the worked specimens are due to the elastic deformation, the plastic deformation and the changing of stress concentration part. Our investigations confirm the advantages of this working method which repaired the structural steel sheets by bolt.
25
Authors: Gong Ting Zhang, Shu Hui Deng, Zhi Wang Zheng, Qin Chun Liu
Abstract: The mechanical properties, optical microstructure and textures of a continuously-annealed cold-rolled high strength structural steel were evaluated. The results show that the experimental steel has good balance of high strength and ductility, and the microstructure is composed of uniform, fine-grained ferrite and a little pearlite. The textures after recrystallization annealing are weak. The intensity of the strongest textures such as {114}<110> and {223}<110> are no more than 4. And the main {114}<110> and {223}<110> components are originated from the hot-rolling process and cold-rolling process, respectively, and preserved after annealing. The application of the experimental steel indicates that it can perfectly satisfy the stamping of some complicated structural parts in the automobile industry.
373
Authors: Marcela Karmazínová, Jindrich Melcher
Abstract: The paper is generally focused on yield and ultimate strengths of structural steels. The attention is mainly paid to the testing and subsequent determination of steel strengths, especially from the viewpoint of the statistical evaluation aimed to obtain the strength values leading to the reliable structural design, in the meaning of general rules given by the European Standard for the structural design of civil engineering constructions. The presented paper deals with the actual yield and ultimate strengths obtained from material tests and their characteristic and design values based on the test results evaluation, versus nominal and design values considered according to European Standard rules and used for the structural design in the usual cases if the steel grade is known. But in the case of existing constructions, sometimes there are no information about the material that the actual steel properties shall be determined using the material tests and their statistical evaluation to obtain such steel properties values which can lead to the reliable structural design. However, approaches of the determination of characteristic and design steel strengths using actual test results are different from the determination of the nominal and design steel strengths given by standard rules. As an illustration the paper summaries the results and evaluations of tests of structural steel performed on the specimens taken from the load-carrying roof structure of the sport stadium aged about 40 years, within the steel construction diagnostics.
585
Authors: Vladimir Ivancivsky, Kristina Parts, Vyacheslav Popov
Abstract: Quenching of steel 45 using high-frequency induction-heating (440000 Hz) with simultaneous shower water cooling was studied. The possibility of liquid-phase creation in the bulk (appr. 0.2 mm) in the material being treated in the absence of melting on the surface was clearly demonstrated by both numerical simulation of the temperature field in the material during hardening and experimental results
129
Authors: Min Li Wang, Zhi Wang Zheng, Gong Ting Zhang
Abstract: The salt-bath annealing was used to study the recrystallization of structural steels as well as the effect of chemical compositions on the microstructure and properties of structural hot dip galvanized steel sheets was investigated in term with the production condition of the No.2 hot dip galvanizing line in Pangang. The optimum annealing temperature range was determined. Experimental results show that the recrystallization temperature of Grade40 and Grade33 is approximately 720°C and 680°C, respectively. Considering the stability of mechanical properties, their optimum annealing temperature are determined to be approximately 720°C. The recrystallization temperature of Grade50 is above 700°C. In order to ensure the margin of strength and the stability of properties of Grade50, the optimum annealing temperature is approximately 780°C.
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