oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Effect of Quenching Temperature on Microstructure and Mechanical Properties of Q1030 Steel  [PDF]
Jianjing Wang, Yonglin Kang, Hao Yu, Wenying Ge
Materials Sciences and Applications (MSA) , 2019, DOI: 10.4236/msa.2019.1010047
Abstract: In this paper, the law of austenitic grain growth gfg is studied under different heating temperature and insulation time, the suitable grain growth model is established, and the regression calculation method is introduced to verify the correctness of the model. The effect of quenching temperature on the microstructure and strength of steel was studied, and it was proved that the quenching temperature had a significant effect on the microstructure and mechanical properties of Q1030 steel. At the quenching temperature of 880°C - 950°C, with the increase of austenitizing temperature, the hardness and strength of Q1030 steel gradually increased, reaching the maximum value at 950°C. During quenching at 950°C - 1100°C, the hardness and strength of Q1030 steel gradually decreased with the increase of austenitic temperature.
Effect of Degree of Deformation on the Mechanical Properties of High Temperature Thermomechanically Treated Steel  [PDF]
J.A. Omotoyinbo,O.E. Olorunniwo,O. Ogundare,O.O. Oluwole
Journal of Applied Sciences , 2006,
Abstract: The development of high strength materials, coupled with good formability, has always been the aim of material scientists. The effect of degree of deformation on the mechanical properties of high temperature themomechanically treated steel (HTMT) has been investigated in this study. It has shown that an increase in percent deformation results in improvement in mechanical properties. In order to have maximum strengthening, heavy deformation and low finishing temperature should be chosen.
Mechanical Proprieties of Steel at High Temperatures  [PDF]
Ana-Diana Anca?,D. Gorb?nescu
Bulletin of the Polytechnic Institute of Jassy, Constructions, Architechture Section , 2005,
Abstract: The experimental test results obtained in the study of steel mechanical proprieties variation in case of high temperatures (fire) are presented. The proprieties are referring to: Young’s modulus, E, the elastic limit, σe, and the characteristic diagram of the material (the rotation stress-strain). Theoretical laws that the model the steel behaviour at high temperature have been elaborated based on the most significant studies presented in the literature.
Theoretical models to predict the mechanical behavior of thick composite tubes
Tita, Volnei;Caliri Júnior, Mauricio Francisco;Massaroppi Junior, Ernesto;
Materials Research , 2012, DOI: 10.1590/S1516-14392011005000092
Abstract: this paper shows theoretical models (analytical formulations) to predict the mechanical behavior of thick composite tubes and how some parameters can influence this behavior. thus, firstly, it was developed the analytical formulations for a pressurized tube made of composite material with a single thick ply and only one lamination angle. for this case, the stress distribution and the displacement fields are investigated as function of different lamination angles and reinforcement volume fractions. the results obtained by the theoretical model are physic consistent and coherent with the literature information. after that, the previous formulations are extended in order to predict the mechanical behavior of a thick laminated tube. both analytical formulations are implemented as a computational tool via matlab code. the results obtained by the computational tool are compared to the finite element analyses, and the stress distribution is considered coherent. moreover, the engineering computational tool is used to perform failure analysis, using different types of failure criteria, which identifies the damaged ply and the mode of failure.
Computer simulation of mechanical properties of quenched and tempered steel specimen  [PDF]
B. Smoljan,D. Iljki?,N. Toma?i?
Journal of Achievements in Materials and Manufacturing Engineering , 2010,
Abstract: Purpose: The computer simulation of mechanical properties of quenched and tempered steel was investigated. The established method of computer simulation was applied in prediction of mechanical properties of workpiece with complex form.Design/methodology/approach: The method of computer simulation of mechanical properties of quenched and tempered steel was established by theoretical analysis of relevant properties which have influence on hardness of quenched and tempered steel, and by regression analysis based on experimental results.Findings: The new method of prediction of mechanical properties of quenched and tempered steel was established. Proposed method of computer simulation of mechanical properties of quenched and tempered steel is based on predicted steel hardness. Hardness distribution of quenched and tempered workpiece of complex form was predicted by computer simulation of steel quenching using a finite volume method. It was found out that mechanical properties of quenched and tempered steel can be successfully predicted by proposed method.Research limitations/implications: The investigation was done on carbon and low alloyed steel. The further experimental investigations are needed for final verification of established model.Practical implications: The established method could be applied in industrial practice.Originality/value: As-quenched hardness distribution is predicted by involving the results of simple Jominy-test in numerical modelling of steel quenching. Estimation of hardness distribution is based on time, relevant for structure transforma- tion, i.e., time of cooling from 800 to 500°C (t8/5). The distribution of mechanical properties in quenched and tempered steel workpiece is estimated based on as-quenched steel hardness, tempering temperature and Jominy-test results.
EFFECTS OF TEST TEMPERATURE AND STRAIN RATE ON THE MECHANICAL PROPERTIES IN AN INTERCRITICALLY HEAT-TREATED BAINITE-TRANSFORMED STEEL
ZLi,DWu,
Z. Li
,and D. Wu The State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang,China Institute of Aeronautical Engineering,Shenyang,China

金属学报(英文版) , 2004,
Abstract: Larger amount of austenite could be retained in an intercritically heat-treated bainitetransformed steel. The elongation and the strength-ductility balance of the steel could be enhanced considerably due to strain-induced martensite transformation and transformationinduced plasticity (TRIP) of retained austenite. The effects of test temperature and strain rate on the mechanical properties and strain induced transformation behavior of retained austenite in the steel were investigated. Total elongation and strength-ductility balance of the specimen reached maximum when it strained at a strain rate of 2.8×10-4s-1 and at 350℃. The relation between test temperature and tensile properties showed the same tendency at three kinds of strain rates. Flow stress increased considerably with decreasing the strain rate.
The Mechanical Threshold Stress model for various tempers of AISI 4340 steel  [PDF]
Biswajit Banerjee
Physics , 2005,
Abstract: Numerical simulations of high-strain-rate and high-temperature deformation of pure metals and alloys require realistic plastic constitutive models. Empirical models include the widely used Johnson-Cook model and the semi-empirical Steinberg-Cochran-Guinan-Lund model. Physically based models such as the Zerilli-Armstrong model, the Mechanical Threshold Stress model, and the Preston-Tonks-Wallace model are also coming into wide use. In this paper, we determine the Mechanical Threshold Stress model parameters for various tempers of AISI 4340 steel using experimental data from the open literature. We also compare stress-strain curves and Taylor impact test profiles predicted by the Mechanical Threshold Stress model with those from the Johnson-Cook model for 4340 steel. Relevant temperature- and pressure-dependent shear modulus models, melting temperature models, a specific heat model, and an equation of state for 4340 steel are discussed and their parameters are presented.
Effects of carburization time and temperature on the mechanical properties of carburized mild steel, using activated carbon as carburizer
Aramide, Fatai Olufemi;Ibitoye, Simeon Ademola;Oladele, Isiaka Oluwole;Borode, Joseph Olatunde;
Materials Research , 2009, DOI: 10.1590/S1516-14392009000400018
Abstract: due to the complexity of controlling parameters in carburization, there has been relatively little work on process variables during the surface hardening process. this work focuses on the effects of the carburizing temperature and time on the mechanical properties of mild steel carburized with activated carbon, at 850, 900 and 950 oc, soaked at the carburizing temperature for 15 and 30 minutes, quenched in oil, tempered at 550 oc and held for 60 minutes. prior carburization process, standard test samples were prepared from the as received specimen for tensile and impact tests. after carburization process, the test samples were subjected to the standard test and from the data obtained, ultimate tensile strength, engineering strain, impact strength, youngs' moduli were calculated. the case and core hardness of the carburized tempered samples were measured. it was observed that the mechanical properties of mild steels were found to be strongly influenced by the process of carburization, carburizing temperature and soaking time at carburizing temperature. it was concluded that the optimum combination of mechanical properties is achieved at the carburizing temperature of 900 oc followed by oil quenching and tempering at 550 oc.
Improvement of Mechanical Properties of Martensitic Stainless Steel by Plasma Nitriding at Low Temperature

YT Xi,DX Liu,D Han,ZF Han,

金属学报(英文版) , 2008,
Abstract: A series of experiments were carried out to study the influence of low temperature plasma nitriding on the mechanical properties of AISI 420 martensitic stainless steel. Plasma nitriding ezperiments were carried out for 15 h at 350℃ by means of DC-pulsed plasma in 25%N2 75%H2 atmosphere. The microstructure, phase composition, and residual stresses profiles of the nitrided layers were determined by optical microscopy and X-ray diffraction. The microhardness profiles of the nitridied surfaces were also studied. The fatigue life, sliding wear, and erosion wear loss of the untreated specimens and plasma nitriding specimens were determined on the basks of a rotating bending fatigue tester, a ball-on-disc wear tester, and a solid particle erosion tester. The results show that the 350℃ nitrided surface is dominated by ε-Fe3N and αN, which is supersaturated nitrogen solid solution. They have high hardness and chemical stabilities. So the low temperature plasma nitriding not only increases the surface hardness values but also improves the wear and erosion resistance. In addition, the fatigue limit of AISI 420 steel can also be improved by plasma nitriding at 350℃ because plasma nitriding produces residual compressive stress inside the modified layer.
受火后钢-混凝土组合梁材料性能试验研究
Experimental analysis of the mechanical performance of steel-concrete girder under fire loading
 [PDF]

姚伟发,黄侨,张娟秀
- , 2015, DOI: 10.11835/j.issn.1674-4764.2015.03.001
Abstract: 为研究火灾高温后组合梁桥的基本材料力学性能与特征,共制作3片具有代表性的缩尺梁模型:简支T形梁、简支箱形梁及连续箱形梁,利用火灾试验炉进行局部三面受火试验,并给出详细的试验方案。通过受火后取样试件与未受火试件的材性试验结果对比,可以发现受火(最高温度在700~900 ℃)对钢板材料的屈服强度及极限强度均有一定程度的降低,降低幅度为10%~20%;而钢板材料弹性模量随温度升高略有变化,但变化值不大。火灾对混凝土强度材性的影响可以忽略不计,但对其冷却后的材料强度有一定影响,相对于常温混凝土其强度会降低5%左右。
In order to investigate the basic mechanical performances of the composite girder under the fire loads, three typical experimental models including simple-support T-section girder, simple-support box-section girder, and continuous box-section girder, were built. After establishing a detailed experimental plan, a fire experiment loaded on three sides was conducted in a laboratory fire furnace. The comparative study on the material characteristics of steel between the models before and after the fire loads showed that the yield and limit strengths decreased by 10%~20 % after fire loads with the 700~900 ℃.The elastic modulus of the steel girder only slightly changed with the increase of temperature. The influence on the concrete material during the fire could be almost ignored; however, 5% decrease of the concrete material strength could be found after cooling off. The results provided good experimental and theoretical foundation for determining the basic material characteristics in the anti-fire design of the composite girders.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.