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2012年, 第19卷, 第2期 刊出日期:2012-02-15
  

  • 全选
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    工艺
  • WANG Li-tao,DENG Chen-hong,DONG Mei,SHI Li-fa,ZHANG Jian-ping
    中国钢铁期刊网. 2012, 19(2): 1-6.
    摘要 ( )   可视化   收藏
    The development of continuous casting technology of electrical steel was analyzed. The technologies and products characteristics of conventional continuous casting, thin slab continuous casting and rolling, middle thin slab continuous casting and rolling and twin-roll thin strip were compared. Conventional continuous casting technology was widely adopted in producing electrical steel; thin slab continuous casting and rolling and middle thin slab continuous casting and rolling technology industrialized electrical steel; and study of twin-roll thin strip casting technology was focused on fundamental experiments.
  • FENG Jun-xiao,XIE Zhi-yin,CHEN Yan-mei
    中国钢铁期刊网. 2012, 19(2): 7-11.
    摘要 ( )   可视化   收藏
    The temperature distribution of iron ore pellet bed in grate has a significant effect on pellet production and quality control, but the related work is scarce. A well-designed test was successfully carried out by means of tracking measurement and the temperature distribution and variation in pellet layers were obtained. The effects of blast temperature, blast velocity and oxidation reaction on the pellet layer temperature were studied. According to the analysis, the inlet air temperature in the up-draught drying zone (UDD) and blast temperature in the Preheating I (PH I) zone should be raised, and the length of the down-draught drying zone (DDD) should be properly increased.
  • ZHANG Jian-liang,REN Shan,SU Bu-xin,LIN Yin-he,LONG Shi-gang
    中国钢铁期刊网. 2012, 19(2): 12-16.
    摘要 ( )   可视化   收藏
    In order to study the combustion characteristics of waste tire particle (WTP), pulverized coal (PC) and their mixture, the contents of CO, CO2 and O2 of off-gas during the combustion of WTP, PC and mixture under the condition of rich oxygen by 0-4% in blast and at 1250 ℃ were measured simultaneously using synthetically infrared analyzer, and then the corresponding combustion ratio was calculated and compared. The results showed that the burning rate of WTP reached approximately 57%, which is much higher than that of PC (only about 18%) in the initial 650 s in fresh air, and then the increase of combustion rate of PC is faster than that of WTP; the combustion rate of PC improved remarkably with the addition of WTP. Meanwhile, the combustion rates of all these materials improved with the increase of oxygen content.
  • LIU Wei,SUN Liang-liang
    中国钢铁期刊网. 2012, 19(2): 17-21.
    摘要 ( )   可视化   收藏
    For steel-making and continuous/ingot casting are the key processes of modern iron and steel enterprises, this paper proposes a batch splitting schedule policy to solve continuous and ingot casting schedule of mixed whole/half charging plan for steel making. First establish the model of continuous and ingot casting schedule of mixed whole/half charging plan according to the complex constraints. Then solve this model by heuristic algorithm. Finally use actual data to prove the proposed algorithm′s validity and analyze the application result in steel plant.
  • WANG Dong-cheng,LIU Hong-min
    中国钢铁期刊网. 2012, 19(2): 22-27.
    摘要 ( )   可视化   收藏
    The shape of strip is calculated by iterative method which combines strip plastic deformation model with rolls elastic deformation model through their calculation results, which can be called results coupling method. Because the shape and rolling force distribution are very sensitive to strip thickness transverse distribution′s variation, the iterative course is rather unstable and sometimes convergence cannot be achieved. In addition, the calculating speed of results coupling method is low, which restricts its usable range. To solve the problem, a new model coupling method is developed, which takes the force distribution between rolls, rolling force distribution and strip′s exit transverse displacement distribution as basic unknowns, and integrates strip plastic deformation model and rolls elastic deformation model as a unified linear equations through their internal relation, so the iterative calculation between the strip plastic deformation model and rolls elastic deformation model can be avoided. To prove the effectiveness of the model coupling method, two examples are calculated by results coupling method and model coupling method respectively. The results of front tension stress, back tension stress, strip′s exit gauge, the force between rolls and rolling force distribution calculated by model coupling method coincide very well with results coupling method. However the calculation course of model coupling method is more steady than results coupling method, and its calculating speed is about ten times as much as the maximal speed of results coupling method, which validates its practicability and reliability.
  • XIANG Jin-zong,,ZHANG Yin,FAN Wen-jun,WANG Ping,HE You-duo
    中国钢铁期刊网. 2012, 19(2): 28-35.
    摘要 ( )   可视化   收藏
    Analysis on the deposition behavior of spray on deposition surface was made and an optimization method for the movement parameters (u, ω) of substrate was obtained. Simultaneously, a mathematical model of growth of tubular preform, specifically aimed at the kind of atomizer that is fixed and with a tilt angle was established. By integrating the optimization method and the mathematical model, the growth process and shape of preform were simulated. The results show that the tilt angle of atomizer plays an important role on the dimensions and shapes of tubular preforms and it can provide a guidance for the development of spray forming equipment.
  • 材料
  • LIU Sheng-fa,CHEN Yang,CHEN Xin,MIAO Hua-ming
    中国钢铁期刊网. 2012, 19(2): 36-42.
    摘要 ( )   可视化   收藏
    Austempered ductile iron (ADI) has several advantages of replacing cast steel and forged steel in many engineering fields. A new Mn-Cu alloyed ADI with excellent mechanical properties has been developed in order to cut the cost and enlarge the application of ADI. The helical bevel gears were made of the new-developed Mn-Cu alloyed ADI. The microstructure and mechanical properties of the standard sample were investigated by optical microscope (OM), scanning electron microscope (SEM) and performance measurement. The results showed that after a series of treatments, the mechanical properties (Rm 10074 to 1200 MPa, A 52% to 88%, HRC 32 to HRC 35, αK 70 to 120 J/cm2) of the Mn-Cu alloyed ADI standard sample could reach European standard EN1564-97/ EN-CJS-1000-5. The surface hardness after helical bevel gears meshing was significantly increased due to the formation of martensite. The bench test and traffic running testing results suggested that the new Mn-Cu alloyed ADI with ultimate life and median life respectively exceeding 30×104 and 50×104 times could replace 20CrMnTi forged steel for manufacturing the EQ140 helical bevel gears.
  • XING Shu-qing,CHEN Zheng-zong,MA Yong-lin,,LI Hui-qin
    中国钢铁期刊网. 2012, 19(2): 43-49.
    摘要 ( )   可视化   收藏
    The effect of refined precipitations and dispersed phases on the toughness of SS400 steel was investigated by rapid tempering with thermomechanical simulation tester, and the electromagnetic induction rapid tempering process was simulated. The conventional tempering and rapid tempering process were proceeded respectively, and both samples were quenched in 10% of agitated iced brine. The tempering temperatures were designed as 560, 620 and 680 ℃, respectively. Rapid tempering specimens were heated at a heating rate of 20 ℃/s, and all samples of these three tempering temperatures were maintained 30, 40 and 50 s with the Gleeble1500-D tester, respectively. The impact test at -40 ℃ were carried out on a Charpy impact machine (CBD-300) with a maximum measurement range of 300 J and the microstructures were analyzed in detail using optical microscope (OM) and scanning electron microscope (SEM). The experiment results show that the upper bainite, martensite and small amount of austenite were obtained in the rapidly quenched samples. In comparison to the conventional process, the matrix microstructure was changed from the larger size and bulk ferrite to the refined banding structure, and the cementites were obviously refined and precipitated inside the grains and along the grain boundaries. The cryogenic impact test implies that the maximum values of impact toughness with holding time of 30 or 50 s are achieved at tempering temperature of 620 ℃. Furthermore, a favorite value of impact toughness with holding time of 40 s is available.
  • JIANG Da-wei,GE Chang-sheng,ZHAO Xiang-juan,LI Jun,SHI Lu-lu,XIAO Xue-shan
    中国钢铁期刊网. 2012, 19(2): 50-56.
    摘要 ( )   可视化   收藏
    A new family of economical duplex stainless steels in which N or Mn was substituted for Ni with composition of 22Cr-80Mn-xNi-10Mo-07Cu-07W-03N (x=05-20) have been developed by examining the microstructure, mechanical and corrosion properties of these alloys. The results show that these alloys have a balanced ferrite-austenite relation. In addition, the alloys are free of precipitation of sigma phase and Cr-nitride when solution-treated at 750 to 1300 ℃ for 30 min. The yield strength, tensile strength and fracture elongation values of experimental alloys solution-treated at 1050 ℃ for 30 min are about 500, 750 MPa and 400%, respectively. Low-temperature impact properties can be improved distinctly with the increase of nickel content. Among the designed DSS alloys, the alloy with Ni of 20% is found to be an optimum alloy with proper phase proportion, better low-temperature impact properties and higher pitting corrosion resistance compared with those of other alloys. The mechanical and corrosion properties and lower production cost of the designed DSSs are better than those of AISI 304.
  • HUANG Fu-xiang,WANG Xin-hua,WANG Wan-jun
    中国钢铁期刊网. 2012, 19(2): 57-61.
    摘要 ( )   可视化   收藏
    The microstructures of austenitic stainless steel strip were studied using color metallographic method and electron probe micro analysis (EPMA). In the cast strips, there are three kinds of solidification structures: fine cellular dendrite in the surface layer, equiaxed grains in the center and fine dendrite between them. The solidification mode in the surface layer is the primary austenite AF mode because of extremely high cooling rate, with the retained ferrite located around the primary cellular austenite. In the fine dendrite zone, the solidification mode of molten stainless steel changes to FA mode and the residual ferrite with fish-bone morphology is located at the core of the dendrite. The retained ferrite of equiaxed grains in the center is located in the center of broken primary ferrite dendrite with vermicular morphology.
  • WANG Xiao,WANG Zuo-cheng,WANG Xie-bin,WANG Yi-ran, GAO Jun-qing,ZHAO Xiu-ling
    中国钢铁期刊网. 2012, 19(2): 62-66.
    摘要 ( )   可视化   收藏
    Microstructures and critical phase-transformation temperature of boron-nickel added Nb-treated high strength low alloy (HSLA) H-beams cooled at different cooling rate, with different deformation were investigated. Continuous cooling transformation (CCT) diagram of this new type of steel was obtained by using Gleeble 1500 thermomechanical simulator. Microstructures and hardness, especially micro-hardness of the experimental steel were investigated by optical microscopy (OM), scanning electron microscope (SEM), Rockwell and Vickers hardness tests. Phase analysis was also studied by X-ray diffraction (XRD). The results indicated that with increase of cooling rate, microstructures of continuous cooled specimens gradually transformed from polygonal ferrite and pearlite, grain boundary ferrite and bainite, bainite and martensite to single martensite. The CCT diagram revealed that slow cooling was needed to avoid austenite-bainite transformation to ensure toughness of this steel. By plastic deformation of 40%, austenite-ferrite transformation temperature increased by 46 ℃, due to deformation induced ferrite transformation during continuous cooling, but Rockwell hardness has little change.
  • M Safavi,S M Abbasi,R Mahdavi
    中国钢铁期刊网. 2012, 19(2): 67-72.
    摘要 ( )   可视化   收藏
    The influence of 001% to 025% of Aluminum content (in mass percent) on the mechanical properties and cold workability of low thermal expansion Fe-33Ni-15Co sheets in the annealed and hot rolled condition was investigated. Addition of Al up to 015% resulted in the increase of ductility and toughness and improvement of workability. Besides, achievement of fine grain structure and increase in the amount of annealing twins caused ductility to improve. Addition of Al higher than 015% led to the increase in oxidation reaction during melting process and to refine under argon atmosphere. This caused the volume fraction of Al containing inclusions to increase and consequently the ductility and toughness to decrease.
  • ZHENG Lei,YUAN Ze-xi,SONG Shen-hua,XI Tian-hui,WANG Qian
    中国钢铁期刊网. 2012, 19(2): 73-78.
    摘要 ( )   可视化   收藏
    Austenite grain sizes in the heat affected zone (HAZ) of a high heat input welded Zr-Ti bearing microalloyed steel are measured under different welding conditions simulated by a Gleeble-1500 thermal-mechanical simulator. The austenite grain growth is divided into two regimes in terms of temperature. When the temperature is lower than 1250 ℃ where the pinning effect of precipitates is strong, the austenite grain size increases slowly with increasing peak temperature, but it increases drastically when the temperature is higher than 1250 ℃ where the pinning effect of precipitates is weak. Based on the experimental measurements, an analytical model for predicting the austenite grain size in the heat affected zone is derived. Model predictions indicate that the initial grain size has little effect on the final one, and the grain growth depends mainly on heat input and peak temperature as well as growth activation energy and exponent. With the use of the model, the width of coarse grained heat affected zone (CGHAZ) for a thick plate is predicted.