八辊矽钢片轧机简介

八辊轧机(MKW 轧机)是西德施劳曼公司的专利,该公司从1952年开始设计制造此类轧机,到目前已生产不同规格的轧机五十多台。我国1968年从西德引进安装在太钢的 U—MKW112—1400轧机,就是该公司最新设计制造的大型八辊轧机。近几年,我国八辊轧机发展很快,有些轧钢厂把四辊轧机或六辊轧机,十二辊轧机改造成八辊轧机。开始是小型的,辊身长200～300毫米,后来义发朕中型的,辊身长有500～700毫米。使用结果证明,这类轧机对轧制特薄带钢优越于四辊轧机。1970年第一     

轧机的命名

轧机的命名是按轧制品种、轧机形式及公称尺寸来称呼。“公称尺寸”对型材轧机来说,以齿轮座人字齿轮节圆直径命名;初轧机则以轧辊公称直径命名;板带轧机是以工作辊辊身长度命名;钢管轧机以生产最大管径命名。有时也以轧机发明者的名字来命名。如森吉米尔轧机、斯特格尔轧机及狄塞尔穿孔机等。还有的以外语名字的字头来称呼,如MKW轧机、PPM扎机、CPE轧机等。     

中小轧机十项新工艺新技术简介

一、高刚度轧机高刚度轧机可分为预应力和短应力线轧机两大类。如北京钢铁学院设计的GY型短应力线轧机,威远钢铁厂的高刚度轧机,河北省冶金厅、邯郸冶金机械厂研制的HB型无牌坊轧机,鄂城钢铁厂采用的预应力轧机以及长城钢厂引进的P500无牌坊轧机等均为高刚度轧机。现简介如下:     

我国中小型轧机改造设想

我国小型轧机的工艺装备布置,除少数几套为连续式、半连续式、跟踪式类型外,其余均为横列式轧机。在横列式轧机中,二列式轧机约占小型轧机总数的1/2,单列式轧机约占2/7。在这些轧机中,除部分装备水平较齐全外,大部均装备水平低,轧机结构陈旧,轧辊弹跳大,生产不稳定。有的轧机精整工序     

支承辊的热裂原因分析及防止措施

复合铸钢支承辊具有耐磨性好、抗剥落能力强、综合使用性能优良等特点,广泛用于热带连轧机、冷带连轧机、平整轧机、中厚板轧机及炉卷轧机等四辊或六辊板带钢轧机[1].     

我国热带需求预测

热带轧机是钢材生产中的主力轧机之一,也是薄板生产最主要的设备.约有50%的钢材是经热带轧机轧制而成,其中的60%以上供冷带作为原料,不足的30%以热轧板交货,还有10%作为焊管和冷弯型钢用的原料.一般生产宽度>1000mm带钢的轧机称为热轧宽带钢轧机,简称为热带轧机;生产宽度450～1000mm带钢的轧机称为中宽带钢轧机;生产带钢宽度<450mm的轧机称为窄带钢轧机.     

大型轧钢机机架加工发展概况

1.国内外轧钢设备简况我国已建成各种轧机约900套,形成轧材生产能力3000×10~4t以上。70年代我国自行设计制造的最大轧机——4200mm特厚板轧机,1700、2300、2450mm轧机,宝钢2050mm轧机,以及引进的1300、1700mm轧机等均属当代水平的轧机。而我国正在使用的大部分轧机仅属50年代左右的装备水平。轧机生产能力相当于炼钢生产能力的75％左右。而世界主要产钢国的炼钢与轧钢的生产能力一般     

专利

连轧机的形状控制方法及装置,张力减径轧机及其运行方法,多层复合板、其制造方法以及专用设备,多辊轧机、操作这些轧机的方法以及采用这些轧机的轧制设备,行星式轧机用的轧辊头[编者按]     

DWG-Ⅰ型轧机的研制及应用

1.前言DWG-Ⅰ型轧机综合了短应力线、预应力轧机的优点。将国外用偏心套进行轧机压下调整的原理及国内小型材轧机的优点集中于一体,并在轧机结构、调整等方面进行新的探索,使轧机强度、刚度、重量、应力线长度、调整等方面均优于其它类型的轧机。     

一种新型宽板轧机的开发及应用

瑞典Oxelsund钢厂3700型轧机是欧洲最早在四辊轧机的出口处装有立辊轧机的板带轧机,立辊轧机显著地提高了板材的宽度精度,从而进一步提高了板材的产量。     

THE SEEPAGE CHARACTERISTICS OF HETEROGENEOUS BODY WITH DIFFERENT SPREADING SOLUTION MODES AND ITS APPLICATIONS

As the dump was a typically heterogeneous body, the seepage was different with varied spreading solution modes. The phenomenon of lamination that occured in the site was simulated using three layers in an indoor experiment, and the seepage effect comparison experiment of the inside spreading solution model and the top spreading solution model have been carried out. In the inside spreading solution mode, the phreatic planar flew without infiltration and the parallel layer motion model was used to calculate the seepage coefficient and equivalent seepage coefficient of each state respectively. In the top spreading solution model, the phreatic planar flew with an even infiltration on the surface, and the vertical layer motion model was adopted to calculate the above coefficient. The results showed that the seepage coefficient of the inside model was larger than the top model in the heterogeneous body, The ratio of them was between 1.42 and 3.07. On the basis of these results, the following new technologies were discussed: installing a few small diameter mechanical pore sand piles with every lamination in the using dump; drilling some holes one-off in the unused dump. These two methods could changed the top spreading solution into the inside model, thus the seepage in the dump was improved.     

DYNAMIC COMPACTION OF PURE COPPER POWDER USING PULSED MAGNETIC FORCE

The compaction of pure Cu powder was carried out through a series of experiments using dynamic magnetic pulse compaction, and the effects of process parameters, such as discharge energy and compacting direction, on the homogeneity and the compaction density of compacted specimens were presented and discussed. The results indicated that the compaction density of specimens increased with the augment of discharge voltage and time. During unidirectional compaction, there was a density gradient along the loading direction in the compacted specimen, and the minimum compaction density was localized to the center of the bottom of the specimen. The larger the aspect ratio of a powder body, the higher the compaction density of the compacted specimen. And high conductivity drivers were beneficial to the increase of the compaction density. The iterative and the double direction compaction were efficient means to manufacture the homogeneous and high-density powder parts.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

LASER CLADDED TiCN COATINGS ON THE SURFACE OF TITANIUM

Laser cladded coatings of TiCN were produced on the surface of titanium. To obtain the optimal techniques, several conditions were tested by varying the laser scanning rate. The choice of shielding gas was also studied. The cladded coatings were then evaluated from the surface mechanics point of view based on their microhardness. The microstructure of some interesting samples was investigated by optical micrographs (OM). The results showed that under the condition of fixed pulse frequency and pulse width, the laser scanning rate and the shielding gas are the main factors influencing the components of coatings. TiCN coatings were decompounded and oxidized during the cladding process in the condition of no shielding gas of N2. X-ray diffraction results indicated that the composite coatings composed of TiCN, TiC, Ti2N, and TiO2 were produced using appropriate techniques. The results indicated that the best condition in terms of the surface microhardness is obtained when the scanning rate is 1.5mm / s, the pulse frequency is 15Hz, the pulse width is 3.0ms, and N2 is chosen as the shielding gas. The microhardness of the composite coatings is about 1331kg · mm - 2, which is about 4 times that of the substrate. The optical micrographs indicated that the cladding zone is made up of TiCN, TiO2, and some interdendritic Ti, but the diffusion zone mainly consists of the dendrites phase, and the cladded depth is about 80m, which is more than 2 times that of the laser nitrided sample. There were no microcracks or air bubbles in the cladded sample, which was cladded using the above optimal techniques.     

PRECIPITATION AND GROWTH OF PEROVSKITE PHASE IN TITANIUM BEARING BLAST FURNACE SLAG

The effects of transformation of slag composition and additive agents on the morphology, the precipitation behavior, the crystal growth, and the volume fraction (VF) of perovskite (CaO·¤TiO_2) crystal in the Ti-bearing blast furnace slags were investigated. As the morphology of perovskite is dispersed in molten slags, the crystal growth mechanism of the melting of fine dendrites and the coarsening of large grains exist throughout the solidification of molten slags. With the increase of CaO and Fe_2O_3 content, VF of perovskite obviously increases. However, high basicity leads to the viscosity of slag, which results in the reduction of the average equivalent diameter (AED). The experimental results showed that the presence of the additives CaF_2 and MnO efficiently decreased the viscosity of the slags, and obviously improved the morphology of perovskite and promoted its growth.     

STUDY ON PROPERTIES OF PULSE ELECTRODEPOSITED RE-Ni-W-P-SiC COMPOSITE COATINGS

The effects of pulse frequency f and duty cycle r on the deposition rate, composition, morphology, and hardness of pulse electrodeposited RE （rare earth）-Ni-W-P-SiC composite coatings have been studied. The results indicate that pulse current can improve the deposition rate of RE-Ni-W-P-SiC composite coatings; W, P, and SiC contents in the coating decrease with the increase of pulse frequency and reach the lowest value at f = 33Hz, whereas the RE content in the composite coatings increases with the increase of pulse frequency. SiC content decreases with the increase of duty cycle, W content reaches the lowest value, and P content reaches the highest value at r = 0.4; pulse current and RE can lead to smaller size of the crystalline grains; however, the effects of different pulse frequency and duty cycle on the morphologies of RE-Ni-W-P-SiC composite coatings are not obvious. The hardness of RE-Ni-W-P-SiC composite coatings is the highest when the duty cycle is at 0.6 and 0.8 and pulse frequency is at 50Hz. At the same pulse frequency, the hardness of RE-Ni-W-P-SiC composite coatings at r= 0.8 is higher than that at r= 0.6.     

Coupled Influence of Temperature and Strain Rate on Tensile Deformation Characteristics of Hot-Extruded AZ31 Magnesium Alloy

To explore the coupled effect of temperature T and strain rate_e on the deformation features of AZ31 Mg alloy,mechanical behaviors and microstructural evolutions as well as surface deformation and damage features were systematically examined under uniaxial tension at T spanning from 298 to 523 K and_e from 10-4to 10-2s-1. The increase in T or the decrease in_e leads to the marked decrease in flow stress, the appearance of a stress quasi-plateau after an initially rapid strain hardening, and even to the occurrence of successive strain softening. Correspondingly, the plastic deformation modes of AZ31 Mg alloy transform from the predominant twinning and a limited amount of dislocation slip into the enhanced non-basal slip and the dynamic recrystallization(DRX) together with the weakened twinning. Meanwhile, the cracking modes also change from along grain boundaries(GBs) and at twin boundaries(TBs) or the end of twins into nearby GBs where the DRX has occurred. The appearance of a stress quasi-plateau, the formation of large-sized cracks nearby GBs, and the occurrence of continuous strain softening, are intimately related to the enhancement of the non-basal slip and the DRX.     

FORMULAS OF TENSION OF CONTINUOUS ROLLING PROCESS

The development of computer controlled continuous rolling process calls for a mathematical expression that can express the inequality condition of "constant flow". Tension is the link of the continuous rolling process. From the condition of dynamic equilibrium, a differential equation of tension is given out. On the basis of the physical rules established from the industrial practice and experimental studies, the law of volume constancy, the linear relation of forward slip and tension, the state equation of continuous rolling, the formula of dynamic tension, and the formula of static tension have been obtained. These formulae reflect the functional relations between tensions, thickness, roll velocity, and time in the continuous rolling process. It is implied that the continuous rolling process is a gradually steady, controllable, and measurable dynamic system. An assumption of predicting the thickness of a steel plate using these tension formulae is also put forward.     

Effects of Welding and rotational speeds on the Microstructure and Hardness of Friction Stir Welded Single-Phase Brass

This study focuses on the effects of rotational and welding speeds on the microstructure and hardness of joints in friction stir welded single-phase brass. Welds were achieved under low heat input conditions at rotational and welding speeds of 400-800 r/min and 100-300 mm/min, respectively. In order to characterize the obtained welds, optical microscopy and Vickers hardness measurements were taken on the weld cross sections. According to the obtained results, increasing the welding speed and/or decreasing the rotational speed caused the grain size of the stir zone to decrease and, hence, improved the average hardness of this region. These results are discussed with respect to the interplay between the welding parameters and the peak temperature in the weld thermal cycle.     

Properties of Mechanically Milled Nanocrystalline and Amorphous Mg–Y–Ni Electrode Alloys for Ni–MH Batteries

Nanocrystalline and amorphous Mg2Ni-type Mg20-xYxNi10(x = 0,1,2,3 and 4) electrode alloys were fabricated using mechanical milling.The effects of the Y content and milling time on the microstructures and electrochemical performances of the alloys were investigated in detail.X-ray diffraction and transmission electron microscopy analyses revealed that the substitution of Y for Mg yields an obvious change in the phase composition and micro morphology of the alloys.When the Y content x B 1,the substitution of Y for Mg does not change the major phase Mg2 Ni,but with a further increase in the Y content,the major phase of the alloys transforms into the YMg Ni4 YMg3 phase.A nanocrystalline and amorphous structure can be obtained by mechanical milling,and the amorphisation degree of the alloy visibly increases with increased milling time.Electrochemical measurements indicate that the discharge capacity of the alloys first increases and then decreases with increasing Y content and milling time.The substitution of Y for Mg dramatically ameliorates the cycle stability of the as-milled alloys,and the mechanical milling more or less impairs the cycle stability of the alloys.Furthermore,the high rate discharge ability,electrochemical impedance spectrum,Tafel polarisation curves and potential step measurements indicate that the electrochemical kinetic properties of the as-milled alloys first increase and then decrease with increasing Y content and milling time.