Zhang Q.,Jiangsu Ship Metallice Materials Quality Supervision and Testing Center |
Wang S.-Q.,Jiangsu Ship Metallice Materials Quality Supervision and Testing Center |
Bao X.-J.,Jiangyin Xingcheng Special Steel Co Ltd |
Gan M.-L.,Jiangsu Ship Metallice Materials Quality Supervision and Testing Center |
And 2 more authors.
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2015
Effect of different heat treatment on fracture toughness of new type R5 mooring chain steel was investigated by crack tip opening displacement (CTOD) test. Microstructure and fracture of the crack propagation zone in CTOD samples were analyzed by SM, OM and SEM. The -20℃ low-temperature mechanical properties of R5 mooring chain steel were tested by high-low temperature tension tester. The results indicate that CTOD fracture toughness of R5 mooring chain steel is greatly influenced by tempering temperatures. The microstructure keeping lath martensite phase direction, the flake and long strip carbides are not evenly distributed on the original austenite grain boundary, the original martensite boundaries and inter martensite lathes when tempering at the range of 570-600℃. It is easy to cause local stress concentration and larger crack growth rates, the CTOD characteristic value approach zero under the action of stress. With the increasing tempering temperature, the carbides of the sample at the range of 600-690℃ gradually aggregate and spheroidize, and distribute uniformly in matrix. It is not easy to cause local stress concentration, crack propagating path deflects and prolongs, crack propagating inhibit, the CTOD characteristic value increasing constantly. After quenching at 950℃ and tempering at the range of 600-690℃, R5 mooring chain steel has high strength and good CTOD fracture toughness. ©, 2015, Editorial Office of Transactions of Materials and Heat Treatment. All right reserved.
Cheng H.-J.,University of Science and Technology Beijing |
Wang F.M.,University of Science and Technology Beijing |
Li C.-R.,University of Science and Technology Beijing |
Tan Y.-P.,University of Science and Technology Beijing |
Wang J.-J.,Jiangyin Xingcheng Special Steel Co Ltd
Jinshu Rechuli/Heat Treatment of Metals | Year: 2010
The continuous cooling transformation curves for 45 steels with varied contents of arsenic were examined by use of thermal dilatometer and metallography. And the microstructure obtained at different cooling rates was analyzed. The room temperature tensile strength and the impact energy of the tested steels were measured and the fractography was observed using SEM. The results show that the ferrite contents increase and the intragranular ferrite phase is easily formed with the increase of amount of As in 45 steel. The addition of As shortens the incubation period of bainite transformation and makes the CCT curve of 45 steel shift to left. At the same time, Ms point is decreased by increasing the As content. When the As content is less than 0. 25%, arsenic has no significant effect on the strength and toughness of 45 steel.
Ji L.,Jiangyin Xingcheng Special Steel Co Ltd |
Shao S.-Y.,Jiangyin Xingcheng Special Steel Co Ltd
Kang T'ieh/Iron and Steel (Peking) | Year: 2011
42CrMo bars with φ45 mm diameter were treated through induction heating, quenching-and-tempering in electron furnace. The effects of heating temperature, cooling intensity and soaking time on the mechanical property and microstructure were analyzed through the comparison of three different processes. The results show that 42CrMo bars which were quenching after induction heat at 900°C for 60s, followed by tempering at 570°C, have finer grain size, more tempered sorbite and good over-all mechanical properties.
Bai L.-G.,University of Science and Technology Beijing |
Liu H.-Y.,Jiangyin Xingcheng Special Steel Co Ltd |
Zhang Y.-L.,University of Science and Technology Beijing |
Miao X.-D.,Jiangyin Xingcheng Special Steel Co Ltd |
Ruan X.-J.,Jiangyin Xingcheng Special Steel Co Ltd
Beijing Keji Daxue Xuebao/Journal of University of Science and Technology Beijing | Year: 2011
The temperature filed of 22CrMoH billets in continuous casting was simulated by using a moving boundary method. Based on a CAFE (cellular automaton-finite element analysis) approach, the microstructure of 22CrMoH billets was obtained and it agrees reasonably well with experimental data. The effects of alloying elements such as Cr, Mo, Si and Mn on the microstructure of 22CrMoH billets were studied. The results suggested that within the specified scope of the 22CrMoH grade, with the contents of Si and Mn increasing, the proportion of equiaxed grains increased, and the number of grains raised, hence the average radius reduced. The increased content of Mo tends to enhance the formation of nuclei, and a proper decrease of Cr element is conducive to raise the ratio of equiaxed grains while has little influence on the number and average radius of grains. Finally, the contents of Cr, Mo, Si and Mn in 22CrMoH steel was optimized, and the simulated results show that the microstructure of 22CrMoH billets is greatly improved: the proportion of equiaxed grains becomes near double, the number of grains increases by 19.96%, and the average grain radius decreases by 9.20%.
Zhang J.,Jiangyin Xingcheng Special Steel Co Ltd |
Zuo J.,Jiangyin Xingcheng Special Steel Co Ltd |
Meng M.,Jiangyin Xingcheng Special Steel Co Ltd |
Lu M.,Jiangyin Xingcheng Special Steel Co Ltd
Jinshu Rechuli/Heat Treatment of Metals | Year: 2015
A 38CrMoAl steel boring bar was suddenly broken during service. The chemical composition, microstructure, mechanical properties and impact properties of the steel were investigated. The results show that the chemical composition meets the requirements, the fracture surface is brittle failure, microstructure is abnormal, and the impact energy is very low, and the impact fracture is also brittle one, which indicates that the main breaking reason is the upper bainite existing in the boring bar, and coarse grains, results from high austenitizing temperature and low cooling speed during quenching. The countermeasures are given according to this analysis result. ©, 2015, Chinese Mechanical Engineering Society of Heat Treatment. All right reserved.