冷床上卸钢液压系统分析改造

本文对冷床上卸钢液压系统存在的问题进行了分析,找出了产生问题的原因,并对原液压系统进行了改造,减少了油液的泄漏,提高了系统的稳定性,减小了维修强度,降低了维修成本,提高了系统的工作效率。     

导向筒挤压成形工艺及模具设计

探讨了导向筒挤压的可行性,对几种工艺方案进行了分析,选择了最优方案并制定了工艺流程,在此基础上设计了导向筒挤压模具。采用冷挤压工艺加工后,提高了零件精度和表面质量,改善了强度和韧性,减少了切削加工量,节约了原材料,提高了生产效率,也改善了零件的组织性能。     

带内螺纹的望远镜镜身注塑模具设计

分析了望远镜镜身的结构,提出了塑件成型及模具设计的关键点,设计了模具的整体结构。设计了可相对运动的组合式型芯,以增加内抽芯机构的运动空间,通过塑件推出时带动螺纹滑块的移动实现了内侧抽芯。设计了矩形型芯镶块、加工了避空结构,采用螺钉固定,解决了狭小空间安装小型芯的问题,避免了模具干涉。采用了锥面配合,提高了模具的定位精度,减小了配合件的摩擦。经生产验证,该模具生产的塑件质量满足图纸要求。     

轧钢加热炉改造

针对轧钢加热炉加热能力不足,炉墙冒火,自动化控制水平落后的情况,对加热炉进行了改造,延长了加热炉的长度,更换了单蓄热式空气烧嘴,并对自动控制系统进行了升级改造,从而消除了炉墙冒火的现象,提高了加热能力和自动控制水平,降低了煤气消耗,取得了良好的经济效益。     

拖拉机导向轮自动焊专机的研制

为加大拖拉机导向轮合件的生产规模, 开发研制了一台自动焊专机, 实现了拖拉机导向轮合件的全自动焊接, 提高了劳动生产率, 满足了规模生产的需求; 还实现了该零件的自动焊接工艺参数的一元化控制, 减小了人为因素对产品质量的影响, 保证了产品的质量, 减轻了工人的劳动强度, 降低了生产成本。     

基于STEP-NC的数控铣削仿真系统的研究

STEP-NC是STEP向数控领域的扩展.STEP-NC使CNC与其它CAX系统之间实现了信息的双向流通,丰富了数控程序的信息含量,提高了CNC的智能化水平.文章利用Visual C 编程语言及OpenGL图形库实现了一个基于STEP-NC的数控铣削仿真系统,构建了基于STEP-NC的软件,规划了其体系结构,论述了STEP-NC类库的设计过程.随后,给出了系统各功能模块的实施细节,分析了各模块实现的关键技术,着重介绍了系统各功能模块的设计与实现,并给出了程序算法及相关流程图.验证了STEP-NC数据模型的可行性.     

型内孕育消除薄壁铸件裂纹

本文通过生产实践,提出了拖拉机变速箱体产生裂纹的原因是内应力超过了抗拉强度所致。采用型内孕育,改善了铸件的组织结构,提高了抗拉强度,抵消了冷却不均匀所产生的内应力,消除了裂纹,提高了经济效益。     

余热锅炉自动上水装置简介

我厂锻工车间的六台余热锅炉安装了自动给水装置,实现了远距离集中控制,避免了干锅和满锅的不安全因素,提高了锅炉效率,减轻了工人的劳动强度,改善了劳动环境,节省了劳动力,原分散管理需24人,现集中管理仅需5人。     

汽车驱动桥U形导向杆座冲侧孔模具设计

对导向杆座零件进行了工艺分析,通过对不同冲孔方法的对比以及考虑零件的适应性,确定了合理的冲孔工艺,并阐述了冲孔模的结构特征,总结了模具设计的要点。经生产验证,该冲孔工艺合理,规避了侧向冲孔工艺模具零件强度不足的风险,简化了模具结构,保证了零件冲孔质量,降低了生产成本。     

床身铸造工艺设计及仿真模拟

研究了床身铸件的铸造工艺方法。比较了几种传统的工艺方案,针对床身铸件导轨长而厚大、壁厚较薄,内腔结构复杂的特点,采用平做立浇工艺。结果表明,该工艺降低了造型高度,简化了模样制作,方便了内腔型芯的制作和安放,同时将导轨部位放置在下型,保证了导轨的质量。在设计中按大孔出流理论设计浇注系统,保证了足够的流速,在导轨的端部设计了独特的阻流和过渡浇口,减少了紊流,改善了热平衡条件。通过对基本工艺的仿真模拟,分析了工艺的可行性,确定了整套完整、合理的工艺方案。     

超大截面钢管坯结晶器优化设计

针对国内超大截面钢管坯结晶器主要依靠进口，同时市场对超大截面特殊钢管坯的旺盛需求，对超大截面钢管坯结晶器进行了研究和开发，优化结晶器总成的结构形式，促进钢管坯连铸技术的发展。     

镁合金ZK60-RE半固态坯的微观组织演变

采用常规铸造法和等径道角挤压分别制备了镁合金ZK60-RE半固态坯;用金相显微镜研究了2种半固态坯料在等温热处理过程中的微观组织演变。结果表明：与传统铸造方法制备的半固态坯相比,采用等径道角挤压制备的半固态坯的晶粒细小、圆整,适合于半固态成形。在等温热处理过程中,2种坯料晶粒粗化的机制是合并长大和Ostwald长大。铸态坯料晶粒液相来源于非平衡凝固时在晶内产生的共晶组织,以及在随后的合并长大过程中晶粒所包裹的液相。随着保温时间的延长,铸态坯料的晶粒尺寸变化情况是：增大、减小然后又增大;而挤压态坯料的晶粒尺寸呈单一增大趋势。     

Effect of original microstructures on microstructural evolution of A2017 semi-solid alloy billets during reheating

The microstructural evolution of the A2017 semi-solid alloy billets provided with rheocasting and extruding/extending forming by shearing-cooling-rolling(SCR) technology during reheating in semi-solid state was investigated. The microstructural differences and their generation causes for both billets were also analyzed. The results show that during reheating, the grains of rheocasting billets grow up and spheroidize gradually with the prolongation of isothermal holding time, the eutectic liquid phase at low melting point forms mainly among the grains. However, the grains of the extruding/extending forming billets grow up abnormally through grain coalescence in the initial stage of the reheating, the entrapment of large amount of liquid within grains occurs, and the grain sizes in the reheating billets are coarse and inhomogeneous. Compared with extruding/extending forming billets, rheocasting billets have smaller and uniform grains in reheating microstructure and can rapidly form liquid phase among grains. Therefore, rheocasting billets are more suitable for the semi-solid forming than the extruding/extending forming billets.     

改善小方坯内部质量的措施

九钢炼钢厂因二次冷却工艺和连铸设备存在问题,小方坯时常产生角部裂纹、中间裂纹、压下裂纹和中心疏松。通过工艺优化和设备改进,使小方坯内部缺陷率降到较低水平。     

半固态A356合金的流变压铸充填性与组织分布

试验研究了压射比压和压射速度对半固态A356铝合金流变压铸充填性的影响。试验结果表明：压射比压和试片的壁厚对新型方法制备的半固态A356合金浆料的充填性影响较大，试片壁厚越大，压射比压越大，型腔越容易充满；为了保证充满型腔，对于10mm的试片，压射比压应≥15MPa，而对于5mm的试片，压射比压应≥20MPa。压射速度对半固态L356合金浆料充填性也具有较大的影响，较高的压射速度有利于半固态A356铝合金浆料的充填；为了保证充满型腔，对于10mm，的试片，压射速度应≥0．384m／s，而对于5mm的试片，压射速度应≥1．152m／s。流变压铸试片的组织分布很均匀，利于获得高质量的半固态A356合金压铸件.     

Semisolid casting with ultrasonically melt-treated billets of Al-7mass%Si alloys

The demand for high performance cast aluminum alloy components is often disturbed by increasing impurity elements,such as iron accumulated from recycled scraps.It is strongly required that coarse plate-like iron compound of β-Al5FeSi turns into harmless form without the need for applying refining additives or expensive virgin ingots.The microstructural modification of Al-7mass%Si alloy billets with different iron contents was examined by applying ultrasonic vibration during the solidification.Ultrasonically melt-treated billets were thixocast right after induction heating up to the semisolid temperature of 583 oC,the microstructure and tensile properties were evaluated in the thixocast components.Globular primary α-Al is required to fill up a thin cavity in thixocasting,so that the microstructural modification by ultrasonic melt-treatment was firstly confirmed in the billets.With ultrasonic melt-treatment in the temperature range of 630 oC to 605 oC,the primary α-Al transforms itself from dendrite into fine globular in morphology.The coarse plate-like β-Al5FeSi compound becomes markedly finer compared with those in non-treated billets.Semisolid soaking up to 583 oC,does not appreciably affect the size of β-Al5FeSi compounds;however,it affects the solid primary α-Al morphology to be more globular,which is convenient for thixocasting.After thixocasting with preheated billets,eutectic silicon plates are extremely refined due to the rapid solidification arising from low casting temperature.The tensile strength of thixocast samples with different iron contents does not change much even at 2mass% of iron,when thixocast with ultrasonically melt-treated billets.However,thixocast Al-7mass%Si-2mass%Fe alloy with non-treated billets exhibits an inferior strength of 80MPa,compared with 180MPa with ultrasonically melt-treated billets.The elongation is also improved by about a factor of two in thixocastings with ultrasonically melt-treated billets for all iron contents of Al-7mass%Si alloys,for example,the elongation of 11% in thixocast of Al-7mass%Si-0.5mass%Fe alloy with ultrasonically melt-treated billets,5% in that with non-treated billets.     

Structure and mechanical properties of AZ31 magnesium alloy billets by different hot-top semi-continuous casting technology

AZ31 alloy billets of 200 mm in diameter were produced by three different processes of conventional direct chill(DC) casting,low-frequency electromagnetic casting(LFEC) and low-frequency electromagnetic vibration casting(LFEVC),respectively.The effect of LFEC and LFEVC on the microstructures,macrosegregation and mechanical properties of AZ31 alloy billets was investigated.In conventional DC casting,the AZ31 alloy billets exhibited coarse grains(about 370 μm) and severe segregation of Al and Zn.In the presence of a solo low-frequency alternating magnetic field or a low-frequency electromagnetic vibration field applied during DC casting of φ200 mm AZ31 billets,grains in the AZ31 alloy billets were effectively refined(about 210 μm) and the macrosegregation of Al and Zn in the billets was greatly decreased.Furthermore,the tensile strength,fracture elongation and hardness of the as-cast AZ31 alloy billets were improved by the processes of LFEC and LFEVC relative to that cast by the process of conventional DC casting.     

超声熔体处理Al-7%Si合金坯料的半固态铸造

由于从循环利用的废料中不断累积增加Fe元素等杂质元素,所以铸造铝合金零部件高性能的要求往往很难实现。要求合金中粗大板条状的含铁化合物β-Al5FeSi在不使用变质剂和昂贵的纯铝锭条件下转变成无害的形貌结构。在凝固过程中通过利用超声振动来检测分析其对具有不同铁含量的Al-7%Si合金坯料的显微组织的变质效果。在感应加热至半固态温度583℃后,立即对超声熔体处理的坯料进行触变铸造,然后对触变铸造的铸件进行微观组织和拉伸性能检测分析。在触变铸造时,要求球形的初生α-Al相充填合金组织中的微小孔洞中,以便首先确定在坯料中通过超声熔体处理使合金显微组织产生变质效果。在605~630℃温度范围内进行超声熔体处理时,初生α-Al相从树枝状晶转变为细小的圆球形形貌。与未进行超声熔体处理的坯料相比,坯料超声熔体处理后合金中的粗大板条状β-Al5FeSi化合物相变得明显细小。升至583℃后进行半固态铸造不会明显改变β-Al5FeSi化合物的尺寸大小,可是却会使初生α-Al相的形貌变得更圆整,这有利于触变铸造。经预先加热的坯料进行触变铸造后,由于低的铸造温度,产生了快速凝固效果,使得合金中的共晶硅层片变得特别细小。在对超声熔体处理的坯料进行触变铸造时,具有不同铁含量的触变试样的抗拉强度变化并不大,即使合金含铁量达到2%。然而,用未处理的Al-7%Si-2%Fe合金坯料进行触变铸造时,其强度较差,仅为80 MPa,而用超声熔体处理的同种合金坯料,其抗拉强度达180 MPa。用超声熔体处理的不同含铁量的Al-7%Si合金坯料进行触变铸造时,其伸长率也提高了约一倍,例如触变铸造超声熔体处理的Al-7%Si-0.5%Fe合金坯料时,试样的伸长率为11%,而未进行超声熔体处理的同种合金触变铸造试件,其伸长率只有5%。     

φ76mm无缝钢管机组使用连铸坯制管的试验

在φ76mm 无缝钢管机组上采用连铸坯制管可降低生产成本。对水平连铸圆坯、弧形连铸方坯所轧圆坯和325kg 钢锭所轧圆坯进行了较全面的质量检查和热塑性模拟试验以及制管试验。结果表明,圆断面连铸坯直接制管是可行的,用连铸方坯所轧管坯制管比用钢锭所轧管坯制管可提高成材率6%左右。     

8011铝合金箔坯退火工艺的优化

通过试验,确定了3.8mm8011铝合金箔坯的最佳均匀化退火工艺为4h升温至540℃,保温16h,降温至350℃出炉空冷,既能达到箔材均匀化退火的目的,又缩短了退火周期,降低了能耗。