高强度一体化铸造桥壳的开发

介绍了驱动桥壳的分类及一体化桥壳的结构,并阐述了高性能一体化铸造桥壳生产工艺为采用树脂砂造型、制芯,一型2件。对于原工艺的工艺出品率低,通过采用发热冒口工艺,降低造型难度,取消边冒口,使工艺出品率由原来的60%~68%上升到80%以上;对于铸件变形,经过多次试验,确定起模3 h后方可浇注,浇注4 h后打箱,可以使铸件变形量小于1 mm;对于铸件偏芯,将原来使用的M5、M10芯撑改为自行设计制造的3联M12芯撑,最终使铸件偏芯不超过1mm。     

气锤砧铁座的铸造

在生产气锤砧铁座时，采用无缝钢管春砂制芯铸造盲孔；涂料中加水玻璃，确保涂层厚度和强度，提高铸件表面质量，放内冷铁，加快铸件冷却速度，确保铸件内部质量，采用浇口通过冒口的浇注方法，提高冒口的补缩效率和铸件工艺出口率。     

耐热球铁深入煤斗铸件浇口冒口工艺设计

箱体类耐热球铁深入煤斗铸件,轮廓尺寸1 920 mm×890 mm×330 mm,璧厚25 mm,材质RQTSi-5.5,重740 kg。粘土砂干型,内腔顶面分型,铸件主要在下型,浇注系统座在芯头上。采用大孔出流理论进行充填设计:1只直浇道φ69 mm,位于横浇道中间,横浇道截面44 mm/54 mm×56 mm,6只内浇道110 mm/130 mm×6 mm。在浇注系统对面设2只溢流补缩耳冒口。用均衡凝固收缩模数法设计计算冒口,直径70 mm,高100 mm。批量生产,生产结果,没有工艺缺陷,生产稳定可靠,工艺出品率93.7%。证明采用大孔出流设计浇注系统,均衡凝固收缩模数法设计耐热球铁箱体类铸件的补缩系统是可靠的。     

铸钢支架熔模铸造工艺优化

通过对冒口大小和内浇道位置分析,采用正交实验法,以浇注温度、浇注速度和模壳预热温度为主要影响因素,以支架(133-9105)铸件的缩松、缩孔为评价指标,利用Pro CAST软件对支架铸件的熔模铸造工艺进行了优化。结果表明,支架铸件适宜的熔模铸造工艺为:浇注温度为1 480℃,模壳预热温度为400℃;最优化熔模铸造工艺下得到的支架缩孔缩松率为0.67%。     

箱体类铸件的生产与质量控制

1箱体类铸件的生产条件及技术要求我公司生产的箱体类铸件是大型农用车辆重要部件,外形尺寸普遍在1 400 mm×400 mm×450 mm左右,材质HT250,铸件本体硬度170~240 HB。采用树脂自硬砂造型、制芯,7 t/h冲天炉熔化铁液。2箱体类铸件的工艺设计2.1浇注系统设计采用半开放半封闭式浇注系统,先开放后封闭有利于挡渣。内浇道分散开设,避开铸件厚大部位,避免铁液冲击砂芯,从而使铁液能够顺利地进入型腔并平稳地充满型腔,浇注位置上部设置出气针和补缩冒口,铁液最后充填部位设溢流冒口。2.2工艺参数设计(1)铸件收缩率:长度方向取1%,由于砂芯或者砂…     

湿型铸造球墨铸铁转子座缩松缺陷的防止

球铁转子座铸件轮廓尺寸φ560×190 mm,主要壁厚45 mm,重量97kg,采用气冲造型.最初采用环形浇注系统底注,顶部设溢流冷冒口,铸件加工后发现有肉眼可见缩松;然后改为顶注,同时采用热压边冒口和冷压边冒口,缩松仍旧未能解决.最后加大热压边冒口压边宽度,减薄与其连接的内浇道,撤除冷压边冒口,终于消除了缩松缺陷.     

浇注系统和冒口联合补缩消除球铁镶圈铸件缩孔缺陷

锻压机用球铁镶圈铸件,牌号QT450-10,外径φ2 364mm,内径φ2020mm,厚120mm,重995kg。为了防止铸件产生铸造缺陷,运用均衡凝固理论,采用顶注、内浇道分散引入、浇注系统和冒口联合补缩工艺。直浇道φ80mm;双向梯形横浇道,上底35mm,下底45mm,高50mm;内浇道宽50mm,厚8mm,长10mm,共24只。在浇注系统的对面安放侧冒口1只,直径φ180mm,高350mm;冒口颈宽220mm,厚20mm,长10mm,用于溢流和补缩。经批量生产验证,铸件内无缩孔、缩松缺陷,上表面无渣孔、气孔缺陷,工艺出品率81%。实际证明：采用均衡凝固理论设计球铁圈形铸件的补缩系统是可靠的。     

大型轴承底座铸造工艺设计优化

介绍了轴承底座的铸件结构及技术要求。利用数值模拟软件,对工艺方案一可能产生的缩松问题进行模拟分析。之后,对方案一的工艺进行了改进:将方案一的卧置造型、卧置浇注工艺改为卧置造型、竖直浇注工艺;采用底注式浇注系统;更改冒口位置,并将原来的1个φ150 mm的发热冒口改为2个尺寸分别为φ150 mm和φ60 mm的冒口。生产结果显示,铸件没有缩松缺陷,满足了客户要求。     

球铁油缸浇注系统补缩无冒口工艺设计

球铁油缸,材质QT500-7,铸件重101 kg,外径φ270 mm,内径φ220 mm,壁厚25 mm,高750 mm,一端球面封口。采用立浇工艺,封口向上。原工艺为阶梯浇注系统,在铸件上部安放1个φ120 mm×200 mm冒口,因冒口下缩孔、浇口引入处缩松,缸壁气孔、夹渣,渗漏废品率54%。为了消除铸造缺陷,新工艺根据均衡凝固原理,采用以顶注为主的浇注系统补缩无冒口工艺,用收缩模数法设计直浇道、横浇道、内浇道尺寸,经批量生产验证,消除了缩孔、缩松、气孔、夹渣缺陷。机加工后经250 MPa×5 min水压试验无渗漏。工艺出品率从77%提高到88%。表明采用收缩模数法计算浇注系统尺寸,用浇注系统补缩的无冒口工艺是可靠的。     

球铁滑轨铸件浇注系统和冒口联合补缩工艺设计

滑轨铸件材质QT450-10,重3 020 kg,轮廓尺寸为长5 800 mm,宽550 mm,高180 mm,热节截面尺寸为180 mm×165 mm。为了防止铸件产生铸造缺陷,采用均衡凝固技术,浇注系统和冒口联合补缩工艺,沿长度方向开设10个内浇道,在浇注系统的对面一侧安置4个补缩-溢流冒口。用收缩模数法设计浇冒口尺寸:1个浇口盆,2个直浇道φ56 mm,双向横浇道44/56 mm×80 mm,内浇道40 mm×10 mm。冒口尺寸φ105/φ200 mm×160 mm,冒口颈厚15 mm,宽200 mm,长20 mm。用此工艺连续生产76件,总重230 t,铸件加工后,没有缩孔、缩松、气孔、渣孔缺陷,全部合格。证明采用均衡凝固工艺生产大型球铁铸件是可靠的。     

锭模斜度及浇注工艺对钢锭质量影响的数值模拟研究

采用THERCAST模拟软件,模拟35 t钢锭的浇注和凝固过程,分析钢锭内部缺陷形成的原因。模拟计算锭模斜度、浇注温度和浇注速度对缺陷分布的影响,得出材料为30Cr Ni Mo8的35 t钢锭最佳浇注工艺方案。     

Numerical Simulation of Macrosegregation in Steel Ingot CastingEI北大核心CSCD

Many key forging components of heavy equipment are manufactured by large steel ingots. Macrosegregation in steel ingots is a key defect formed during the solidification process. Over the past few decades, numerical modeling has played a more and more important role in the study of macrosegregation. Various models have been developed and applied to different ingot casting processes. This paper focused on the application of macrosegregation models to the steel ingot. Firstly, the formation mechanism and influencing factors of macrosegregation were introduced. Then, the existing macrosegregation models and their recent development were summarized. Macrosegregation models accounting for such mechanisms as solidification shrinkage- induced flow and mushy zone deformation were analyzed, respectfully. To model macrosegregation due to solidification shrinkage, the key was to solve the free surface. A simple derivation showed that the multi-phase (including gas phase) models were equivalent to the VOF-based segregation models in dealing with the shrinkage-induced flow. Finally, our recent research work on numerical modeling of macrosegregation in steel ingots was illustrated, including application of the developed multi-component and multi-phase macrosegregation model to a 36 t steel ingot, and numerical simulation of multiple pouring process. The carbon and sulphur concentrations at about 1800 sampling points, covering the full section of a 36 t ingot, were measured. By detailed temperature recording, accurate heat transfer conditions between the ingot and mould were obtained. Typical macrosegregation patterns, including the bottom-located negative segregation and the pushpin-like positive segregation zone in the top riser, have been reproduced both in the measurements and the predictions, The carbon and sulphur concentrations predicted by the three dimensional multi-component and multi-phase macrosegregation models agreed well with the measurements, thus proving that the model can well predict the macrosegregation formation in steel ingots. As for the multi-pouring process simulation, the results show a high concentration of carbon at the bottom and a low concentration of carbon at the top of the mould after the multi-pouring process with carbon content high in the first ladle and low in the last ladle. Therefore, the multiple pouring process could get the initial solute distribution with the opposite form of segregation. Such carbon concentration distribution would reduce the negative segregation at the bottom and the positive segregation at the top of the solidified ingot, thus proving the ability of the multiple pouring process for the control of macrosegregation.     

Numerical simulation of central shrinkage crack formation in a 234-t steel ingot

Central shrinkage crack is a common defect encountered in steel ingot casting. It is necessary to limit the degree of crack in case of further propagation in forging. A 234-t steel ingot was dissected to check the internal quality, and a central shrinkage crack band of 1,400 mm in height and 120 mm in width, was found at a distance of 450 mm under the riser bottom line. Then, thermo-mechanical simulation using an elasto-viscoplastic finite-element model was conducted to analyze the stress-strain evolution during ingot solidification. A new criterion considering mush mechanical property in the brittle temperature range as well as shrinkage porosity was used to identify the shrinkage crack potential, where the degree of shrinkage porosity is regarded as a probability factor using a modified sigmoid function. Different casting processes, such as pouring speed, mould preheating and riser insulation, were optimized with the simulation model. The results show that fast pouring, proper mould preheating and good riser insulation can alleviate shrinkage crack potential in the ingot center.     

顶注浇注系统在消失模筒形铸件中的应用

在金属铸造工艺设计中,优先顶注是多数金属铸件所遵循的铸造原则。简要介绍真空消失模铸造采用顶注工艺批量生产管件、大型电机壳和钢锭模产品的实践应用。采用顶注工艺,浇注系统简单、工艺出品率高、浇注温度低,节约生产成本。     

E型磨煤机钢球消失模铸造工艺及数值模拟

用消失模工艺铸造E型磨煤机用耐磨空心钢球,设计了侧注、顶注两种工艺方案,并用华铸CAE分析系统对两种方案进行充型和凝固模拟,并对两种方案的模拟结果进行分析和对比。另将试验结果和模拟结果作对比。分析了在铸造大型空心钢球方面,用消失模工艺方法生产的优势和劣势。     

水冷锭盘的铸造工艺

为满足水冷锭盘的性能要求,对其材质进行了选择,设计了冷却管的管形及布置,计算了冷却管的长度,着重分析了冷却管防渗碳技术,确定了水冷锭盘造型及熔炼浇注工艺.防渗碳、无热阻水冷锭盘的冷却降温性能显著,可实现铸锭定向凝固,改善其微观品质,提高铸锭出品率,降低模耗.     

基于铜包铝复层圆坯水平连铸的数值模拟与试验研究

利用Fluent TM模拟软件研究芯部铝液浇注温度、拉坯速度等工艺参数对水平连铸铜/铝复层铸坯温度场、液相率及流场的影响,并进行试验验证。结果表明,芯部铝液浇注温度越高,与铜管接触的铝液温度越高,液穴深度越深,铝铜之间越易发生反应;拉坯速度越快,铝液液穴深度越深,液态铝与铜管壁接触时间越长。铝液浇注温度控制在710~730℃,拉坯速度为200mm/min时可以获得优质的铜/铝复层铸锭,模拟结果与试验结果具有较好的一致性。     

基于均衡凝固理论的锌锭模铸造工艺数值模拟

基于铸件均衡凝固理论,拟定锌锭模铸件的浇注方案及浇注系统的设计计算;然后利用Pro/E和Procast软件,模拟锌锭模铸件的浇注工艺过程.对比结果表明,两者基本吻合.通过模拟可以预知铸件可能产生的铸造缺陷,优化铸造工艺.     

Formation mechanism of shrinkage and large inclusions of a 70t 12Cr2Mo1 heavy steel ingot简

Shrinkage cavities and large inclusions are serious internal defects of heavy steel ingot and influence the quality of subsequent forgings.In order to remove these two types of defects,a 70 t 12Cr2Mo1 heavy ingot fabricated by vacuum carbon de-oxidation process was sectioned and investigated by means of structure observation and EDS analysis.To further study the forming mechanism of shrinkage and inclusion defects and find possible solutions,simulation on pouring and solidification processes was also carried out using Fluent and ProCAST software,respectively.Results show that the shrinkage defects do not appear in the middle-upper part of the ingot.The critical value of shrinkage cavity criterion is ascertained as 0.013 on the basis of sectioning investigation and simulation results,which can be used in computer simulation to predict and avoid shrinkage defects in production of 12Cr2Mo1 ingots with different weights.However,large inclusions are found at the bottom of the ingot body.The bad thermal conditions of the ingot surface and large amount of entrained slag are the main origin of the large inclusions.The simulation result of the pouring process shows that large inclusions may be eliminated by combined measures of improving the top thermal condition and controlling the height of rudimental molten steel in the ladle to above 300 mm.     

采用高炉铁液生产大高径比灰铸铁钢锭模

介绍了大高径比钢锭模的铸件结构及技术要求,详细阐述了生产该铸件的铸造工艺:采用横做横浇工艺,封闭式浇注系统,浇口比为ΣF直:ΣF横:ΣF内=1.4:1.2:(1.1~1.0),选用尺寸为φ50 mm的出气冒口;呋喃树脂砂造型,将球铁芯骨固定在芯盒内,砂层厚度为40~50 mm;大高径比钢锭模采用高炉铁液浇注,出铁温度控制在1 400±20℃,在出铁过程中,向流铁槽内加入粒度为3~6 mm的75SiFe及65MnFe,加入量分别为0.3%~0.5%、0.5%~1.0%,铁液最终成分为w(C)4.1%~4.6%、w(Si)0.6%~1.0%、w(Mn)0.7%~1.0%、w(P)≤0.10%、w(S)≤0.03%;浇注前扒渣3~5次,浇注温度控制在1 260~1 300℃,浇注速度2~3 t/min。最终生产的铸件内壁平直度公差为3~5 mm,内壁光滑,抗拉强度也符合技术要求。