Papers by Keyword: Plate Thickness

Abstract: Single point incremental forming is a major process in a number of different industrial applications. Blank are easily found around us from furniture and household equipment to industrial machinery and equipment. To ensure high-quality sheet metal, it is vital to consider the influence of parameters. Accordingly, in this paper, the parameters affecting product quality are analyzed. Through the testing process, we obtain the parameters that help the product achieve high quality in terms of mechanics, which is an important first step for the process of developing the technology.

Abstract: Based on the powerful finite element analysis software-ANSYS Workbench co-simulation platform, boom buckling instability capability has been studied by using the seamless interface of DM(Geometry Modeler),Mechanical(Structure Analysis)and DX(Optimization Design)module. Firstly, the trend figure that the thickness of each plate increasing has influenced on the overall buckling limit has been got. Applying the rule, the actual structure was optimized and the optimal combination of thickness was found. Under the condition of the buckling limit, the weight of the crane arm has a significant reduction compared with the actual structure. Finally, this result which is reasonably practicably provides a reference method for engineering mechanism design including large-scale crane arm in the future.

Abstract: Residual stresses are generated as a result of non-uniform temperature distribution during welding and particularly cooling process during fabrication of the welded parts. Residual stresses have a major effect on the overall performance of a component in service. In this instant, the residual stress in the form of angular distortion is primarily caused by shrinkage on longitudinal and transversal direction. Several single v-butt joints on structural steel plates of SS400 are investigated by using different plate thickness and welding positions (1G and 3G). GMAW method was used in the welding process. Measurement of residual stress was carried out on a plate with the thickness of 16 mm on longitudinal, transversal and normal direction by using neutron diffraction method. Results showed that the angular distortion of the welded plates increase with the increase of plate thickness. Welding by vertical position (3G position) resulted in a bigger angular distortion compared to flat position (1G position). The distribution of residual stress varied between tension and compression residual stress along welded area with the range of -10 mm to 10 mm. Measurement of residual stress on the longitudinal direction has the greatest value among two other directions.

Abstract: The curved box-girders of Hefei Xinqiao International Airport Terminal were taken as a background of this article. Aiming at the type of the cross section, thickness of the steel plates and curvature of the beam axis, parametric analysis was carried out to evaluate the ultimate bearing capacity of this kind of curved box-girder. Using the finite element analysis software ANSYS, the effects of former three parameters was calculated. From the results, it could be found out that the ultimate bearing capacity increases as the section aspect ratio grows, and it increases linearly as the thickness of the flange and web plate grows. In addition, the ultimate bearing capacity increased and decreased with the increment of the curvature of the beam axis R. The finite element results provided a theoretical basis for experimental research and analysis of the local models provided reasonable suggestions for design as well.

Abstract: This paper investigates hardness, toughness and microstructures of A572 Gr.50 steel built-up box-section welds jointed by electroslag welding (ESW). The welding heat from ESW, for example, is considered one of the main factors reducing steel toughness and causing the connections to fracture. The result of the investigation indicates that the 25- and 50-mm plates have small difference in hardness, toughness and grain sizes. The A572 Gr.50 steel absorbs energy more than 105J, satisfying the code requirement of 27J at 0°C in the Charpy impact tests. However, the welding heat increases the size of coarse grain and hardness in the heat affected zone (HAZ), reducing the Charpy value to 14.9 J. The HAZ absorbs much less energy than the base material, and this difference is more significant in the weld of 50-mm plates. Based on the investigation, it can be suggested that to enhance the seismic performance of welded steel structures, not only the toughness of base material, but also welding heat need further controlling.

Abstract: After the mechanisms of laser peen forming (LPF) were analyzed, the effect of sheet metal’s thickness on LPF was discussed in theory. The analysis model that residual stresses brought sheet bending was established, and the relationship between thickness and arc height of sheet metal was obtained. The process of laser shock wave loading during LPF was modeled, and then the residual stresses and deformation of the peened sheet were simulated by ABAQUS software. The results indicated that LPF use bending moments caused by residual stress to induce deformation, which was agreed with the theory analysis. The curvature of sheet metal induced by LPF decreased as the thickness increased, the arc height formed by bending was inversely proportional to thickness square of sheet metal on the whole. This research also has significance for the control of LPF and the investigation of further experiment

Abstract: In this study, the effect of thickness on the fracture toughness of the steel plate with the thickness of 80mm has been investigated by the wide plate tensile test and ESSO test. The fracture toughness for crack initiation and propagation was evaluated quantitatively for the full thickness specimen. It was found that EH-36 grade steel with the thickness of 80mmt showed the KIC value of 164kgf/mm1.5 at -145°C. Also, large-scale ESSO test result showed that the steel with the thickness of 80mm had 520kgf/mm1.5 at -10°C. Although it was known that the fracture toughness decreases with the increase of the plate thickness, EH-36 grade steel with the thickness of 80mm had enough values of fracture toughness to prevent the crack initiation and arrest the brittle crack propagation.

Abstract: Effect of the severe deformation by multi-pass rolling on microstructure and tensile properties was analyzed in terms of rolling temperature, plate thickness, and cooling rate for a modified API X65 steel containing B. The plates, 80 and 50 mm thickness, were rolled six times by 20%/pass (total 75%) to 20 and 12 mm, at 1023 K of unrecrystallized γ region or 973 K of intercritical (α+γ) region, and then quenched in water or oil. All specimens except one oil-quenched condition showed relatively high UTS 700-830 MPa and the continuous yielding(YR～0.6), typical mode of the (ferrite + martensite (bainite)) dual phase microstructure. In contrast, one oil-quenched specimen with the 973 K-20 mm condition, exhibited the discontinuous yielding (YR～0.8), indicating that the microstructure basically consists of ferrite plus pearlite, as well as a relatively low UTS 660 MPa. The degree of deformation really occurring within materials, i.e., strain hardening seems to be enhanced with a decrease in deformation temperature. As the degree of deformation increases, the remaining austenite, not dynamically transformed to fine ferrite, becomes increasingly unstable. A lower hardenability of this remaining austenite thus would lead to a higher possibility to transform into the (ferrite + pearlite) structure of lower strength rather than the (ferrite + martensite (bainite)) of higher strength.

Abstract: The mechanical properties of a bainitic microstructure with slender ferrite plates (20-65 nm in thickness) in a matrix of carbon-enriched retained austenite were characterized. The microstructure is generated by isothermal transformation at temperatures in the range 200-300°C. A yield strength as high as 1.5 GPa and an ultimate tensile strength between 1.77 to 2.2 GPa was achieved, depending on the transformation temperature. Furthermore, the high strength is frequently accompanied by ductility (£ 30%) and respectable levels of fracture toughness (< 45 MPa m0.5). This unusual combination of properties is attributed to the exceptionally fine scale of the carbidefree bainitic microstructure and the associated retained austenite.