Advanced Materials Research Vols. 602-604

Abstract: The microstructure of metal material would change with temperature, the roughness of the metal fracture would also vary. The mechanical properties of materials closely related to roughness of fracture. In this paper, after high temperature the crack strain fatigue fracture roughness and fatigue mechanical properties were analyzed for 16MnR steel. Further, relationships between roughness of fatigue fracture and temperature were also discussed.

Abstract: The effects of controlled rolling and controlled cooling parameters on the microstructure and mechanical properties of 550MPa grade engineering mechanism steel were investigated in the industrial trial conditions. The results show that the mechanical properties of 550MPa grade engineering mechanism steel are obviously improved by controlling finishing rolling temperature ranged from 780°Cto 850°C, and by using accelerate cooling after rolling, ferrite grains are refined markedly of the steel which possess excellent strength and toughness behaviors.

Abstract: Influence of different heat treatment on microstructure and mechanical properties of mining machinery steel Plate containing molybdenum niobium was investigated. As-rolled steel plate was processed by normalizing and normalization-tempering respectively. Mechanical properties of as-rolled steel plate, normalizing steel plate and normalizing-tempering steel plate and their microstructures was made a contrast. The experiment result showed that formation of coarse ferrite grain in as-rolled state leads to lower impact toughness. Normalizing treatment can refine coarse ferrite formed in hot rolling process but formation of carbon oversaturation induced new dislocation and distortion. Processing of proper normalizing-tempering can eliminate coarse ferrite in as-rolled state and relieve new dislocation and distortion formed in normalizing process, and therefore made the mechanical properties of the as-rolled plate be the best state.

Abstract: Based on the phenomenon of fracture lamination of 10CrNiCu steel, micro-analysis and Scanning Electron Microscope are applied, and results show that there is a lot of MnS inclusions near the fractures of 10CrNiCu steel，and the banded Structure caused by continuous cast is serious. The improve means is mentioned.

Abstract: In cognizance of the problems of low desulphurization rate for hot metal, large sulfur-recovery in converter, as well as high sulfur content in products when producing non-oriented electrical steel with vanadium-content hot metal, countermeasures have been carried out. Sulfur content in non-oriented electrical steel is decreased obviously with the study on technologies of desulphurization for hot metal with vanadium & titanium, sulfur-recovery control in converter, and desulphurization in RH refining process as well. The results of industrial tests show that the rate of w（S）≤0.008 % is as high as 100 %, and the rate of w（S）≤0.005 % reaches 91.43 %. And besides, sulfur mass fraction is 0.004 2 % on average (0.001 9 %~0.006 9 %).

Abstract: The research in the cryogenic treatment of tool steels and other alloy steels is important as it causes substantial increase in the wear characteristics of alloy and tool steels. The present day research of this technology indicates precipitation of submicroscopic carbides referred to as eta carbides. This work comprises of reviewing the carbide types that form during heat treatment of high speed steels and presenting the results of the experiment for finding eta carbide in the cryogenically treated AISI T42 high speed steels using advanced microscopy. The results of this work indicate the contribution from the other secondary carbides (other than eta carbides) in the enhancement of wear characteristics in high speed steels.

Abstract: The thermodynamics and kinetics factors about ladle vanadium extraction are introduced firstly. According to the real production in the resources comprehensive utilization test pilot of Pangang, the causes of temperature controlling, shortage of oxygen supply as well as the difficult for slag skimming are all analyzed in detail and the solutions are put forward at the same time. Under the real production conditions, if controlling the temperature of molten pool between 1450～1500°C,keeping the bottom blowing smoothly, meeting the oxygen supply of 1400 Nm3/h and adding adequate coolant at better time it will get good vanadium extraction results

Abstract: A new method of the estimation of influence of the iron ore materials and coke metallurgical properties on the efficiency of blast furnace smelting is developed. It consists in the following stages: the laboratory tests with the definition of the iron ore materials and coke metallurgical properties; the analytical study of the influence of these characteristics on the efficiency of blast furnace smelting using by mathematical models; the experimental industrial and industrial tests. The developed methodological basis allows to obtain improved criteria for evaluating the metallurgical characteristics of the raw materials and to explain the mechanism of their effect on the reaction of the direct and indirect recovery in the blast furnace. Therefore it allows to formulate recommendations to improve the blast furnace smelting technology.

Abstract: The anodic polarization curves of 2Cr13 stainless steel with various RE contents in 3.5% NaCl neutral solutions have been measured by electrochemical methods. The effect of Ce on pitting corrosion resistance of 2Cr13 stainless steel has been studied by the metallographic examination. The results show that sulfide and other irregular inclusions are modified to round or oval-shaped Ce2O2S and CeS after adding Ce to 2Cr13 stainless steel.Ce makes sulfide, and other irregular inclusions change to dispersed round or oval-shaped Ce inclusions, effectively inhibits the occurrence of pitting corrosion, thereby enhancing the corrosion resistance of 2Cr13 stainless steel.

Abstract: The microstructure evolution characteristics and those effects on microhardness of HSLA (high strength low alloy) 100 steel secondary quenched in the two-phase region were investigated. The results show that the mixed microstructure of ferrite and the M-A（mastenite-austenite）islands can be obtained in the intercritical quenching region. A small amount of island structure distributing along the lath ferrite quenched at 700°C is observed by transmission electron microscope (TEM). With the quenching temperature increasing, the island structure increases in quantity and coarsens in shape, at the same time, the ferrite gradually transform from single lath morphology to polygonal shape with the dislocation density lowing. When quenched at 820°C, the microstructure reverts to lath bainite. There is a good correlation between Vickers hardness value and the volume fraction of martensite or bainite HSLA100 steel quenched in the two-phase region. The microhardness value of the steel continually increase from 240HV to 320HV quenched at the range of 700°C to 820°C, and then keep a very small fluctuation around 320HV when the temperature exceeds to 820°C.