由搅拌铸造方法制备SiC增强铝基复合材料,再通过搅拌摩擦加工(FSP)对其内部组织进行重构,结果表明,材料致密度提高,铸造缺陷大幅减少,复合材料的基体组织被显著细化,且SiC颗粒在FSP处理后分布更加均匀,材料的抗拉强度和延伸率均得到了显著提升,摩擦磨损性能也得到了改善.

介绍了某球墨铸铁件在冒口颈处出现的较为严重的渣眼缺陷,分析了球墨铸铁件冒口颈处产生渣眼的主要原因,认为铁液在内浇道处因流速较快,喷溅形成的二次氧化渣聚集在铸件冒口颈处形成渣眼缺陷,并制定了相应的改进措施:通过优化浇注系统,将封闭式改为半开放式浇注系统,确定了合适的浇注系统分配比例,更改内浇道的主入水位置,将冒口颈处的入铁速度由原来的63 cm/s降至41 cm/s.生产结果显示:累计生产的4000多件铸件表面光滑,未发现铸件冒口颈附近的渣眼问题.

采用正交试验分析了温度、保温时间和冷却速率对QT400-18 AL低温冲击韧性和抗拉强度的影响,研究了Cr等强碳化物元素导致其低温冲击韧性下降的机理,并采用热处理技术降低晶界偏析并提高晶粒度等级,从而提升材料的低温冲击韧性和抗拉强度.结果 表明:Cr等强碳化物形成元素超标,使韧性大幅降低.通过超高温均匀化退火,低温冲击韧性在提升的同时晶粒粗大导致抗拉强度有所下降.采用细晶强韧化热处理工艺可以同时提升抗拉强度和低温冲击韧性.

采用扫描电镜(SEM)、X射线衍射仪(XRD)和透射电镜(TEM)等测试手段,研究了La、B元素联合变质对Al-Si合金中初生相形核的影响.结果表明,在亚共晶Al-Si合金熔体中,LaB6的形成对凝固过程中初生α-Al相具有细化作用,但这种作用会因Ti与B生成TiB2而受到抑制.在过共晶Al-Si合金熔体中,LaB6的形成对初生Si相以及共晶Si相形核存在促进作用;TEM分析显示,LaB6相的{110}晶面与初生Si相的{111}晶面有着良好的晶体学位相关系,可作为初生Si相的非均质形核核心.

文章通过分析和总结立体光固化技术在机车零部件设计开发和铸造产业中的应用,阐述了以SLA为代表的3D打印技术与现代制造业的紧密结合,给机车零部件设计开发和铸造工艺的制定提供了新的思路和快捷途径.

SLS and SLA technologies of 3D-printing were applied to developing the railway coupler casting. A good combination between the 3D-printing and the traditional casting process was realized. With the help of 3D-printing technology, the coupler casting with good internal and external quality was developed rapidly.

在工程机械领域,工况不同,对材料的要求也不同.为了满足中等冲击条件下较高的耐磨性能需要,研制了低合金贝氏体钢.对低合金贝氏体材料的成分和热处理工艺进行设计,并与其它耐磨材料(低合金钢,高锰钢,高铬铸铁)的力学性能、金相组织、耐磨性能等进行了比较.试验证明:低合金贝氏体材料在中等冲击条件下,具有较高的硬度和耐磨性能,具有优良的综合机械性能.

中间车钩原铸造工艺采用酯硬化水玻璃砂生产的坭芯易导致铸件内腔皱纹缺陷超标.为了解决此问题,采用了3D打印技术制作覆膜砂坭芯的新工艺.结果表明,使用3D打印的覆膜砂坭芯后,车钩体内腔表面质量得到显著改善,解决了车钩内腔皱纹超标的问题,铸件质量符合JIS-G0588标准规定.

磁轭铸钢件在铸造试制过程中,铸件底部法兰面出现了裂纹缺陷,顶部梅花孔面加工过程中有气孔缺陷显现.文章从铸造冷铁工艺、造型工艺和熔炼浇注方面分析了缺陷产生的原因,提出改进措施并优化了铸造工艺,消除了裂纹和气孔缺陷,保证了产品的质量.

以HXD1D型机车为平台,展开对客运机车制动盘和闸片的技术研究,并开发了适合160 km/h及以上速度等级客运电力机车的铸钢制动盘和粉末冶金闸片.经过大量的1∶1型式试验验证,其满足相关的技术要求.装车考核结果显示,机车铸钢制动盘和粉末冶金闸片完全满足160 km/h及以上速度等级客运电力机车的实际使用要求.

The centrifugal melting technology is studied for taking the steel backing duplex metal sliding bearing as the subject. It can obtain steel backing and duplex alloy composites with high strength and homogeneous by reasonable structure design of steel backing and centrifugal melting parameters. The analysis of alloy microstructures show that,lead is dispersed in the matrix as the single substance,the steel backing and the inner and outer alloy are metallurgical bonded well by atomic diffusion.

The invention discloses an insulating and exothermic riser for metal-mould low pressure casting and the manufacturing method and application thereof. The insulating and exothermic riser comprises a riser bush and a breaker core, wherein a heat insulating material and/or an exothermic agent is arranged in the riser bush, the breaker core is coaxially arranged at the lower end of the riser bush, and a feeding cavity is formed between the breaker core and the lower end of the riser bush. The insulating and exothermic riser is characterized in that an annular precoated sand sleeve is formed on the periphery of the bonding surface of the riser bush and the breaker core through sand blowing. According to the insulating and exothermic riser, the annular precoated sand sleeve is additionally arranged on the periphery of the bonding surface of the riser bush and the breaker core through sand blowing of a hot box. When the insulating and exothermic riser is applied to the metal-mould low pressure field, the problem of looseness of a local thermal center can be solved simply by embedding the insulating and exothermic riser in a local loose piece, the cost and time for developing a die are saved greatly, efficiency is improved, feeding efficiency is high, and aluminum materials are saved.

以HXN5B机车双金属止推轴承为研究对象,通过合理优化化学成分、钢坯模具等设计,对其采用离心熔铸一次成型工艺制作毛坯,并进行化学成分和组织性能检测.实际结果表明,双金属止推轴承止推面处径向和轴向的化学成分基本无偏差,钢背与合金层出现了Fe与Cu和Sn原子的互扩散,界面结合良好,金相组织达到2级以上标准,碾平试验中合金层表面有裂纹但未出现合金层与钢背分离现象,双金属层间实现了良好的冶金结合,获得了性能优良的合格铸件.

研究了高强度铝合金AlSi7MgA的流动性和热裂倾向,分析了导温率、收缩率以及外部压力对凝固补缩行为的影响.以机车齿轮箱产品为例,通过充型流动、凝固补缩模拟计算以及缺陷产生原因分析,阐明了低压铸造工艺的特点.

G20Mn5是一种广泛使用的低碳低合金铸钢,具有可焊性好、裂纹倾向小、综合力学性能优异等特点.该材质铸件的力学性能与化学成分选择、热处理工艺和铸造工艺密切相关.本文以G20Mn5在国外新型转向架支架中的应用作为实例,研究了上述工艺环节的具体参数选择对铸钢件力学性能的影响规律.

借助SINOVATION软件对磁轭进行三维实体建模及铸造工艺设计,采用MAGMA软件对磁轭铸造工艺进行模拟分析,并对该工艺方案下的铸件进行了实体浇注及质量检测。结果表明:在合理设计浇注系统和冷铁等工艺参数条件下,采用SINOVATION软件计算的模数大小和冒口尺寸能满足铸造工艺要求,为实际生产提供指导。

The adaptor is an important structural component between bogie and shaft in diesel locomotive.Comparing with domestic counterparts,EMD adaptor has more complicated structure,which blocks the feeding channel.Besides,request of appearance and internal quality of this component is strict.All locations of the casting should be level 3 radiographic testing according to ASTM E446/E186.To achieve the technical request,casting process should be investigated.In this paper,Magmasoft is used to calculate the hotspot in the casting and porosity defects are estimated.The casting process is designed and optimized according to the rule of progressive solidification.The results show with semicircular allowance and insulated riser,the internal quality of casting was assured and reaches the customer's request.

采用模拟软件Magma对铝合金轴箱前盖铸造工艺方案的充型及凝固进行模拟,分析对比了2种方案各自的优缺点。综合考虑,确定采用水平压边胃口顶注方式,并在此基础上采取保温砂套、局部冷却水管激冷等改进工艺,实现了冒口的圆满补缩,铸件获得了良好内部质量。同时在压边冒口下方增设内浇道以及使用过滤片,确保了铸件外观质量。

B+级铸钢(ZG25 MnCrNi)是广泛应用于生产摇枕、侧架的重要材料,热处理工艺一般为900℃固熔3～4h后吹风冷却,其金相组织为均匀细小的等轴铁素体+珠光体组织.近期一些生产厂家发现铁素体与珠光体基体中出现了一定比例的大块状珠光体组织.通过对该类异常组织的金相、元素分布与力学性能的分析,发现形成大块状珠光体的原因主要是由于热处理局部温度不均匀引起的残余铸态组织和遗传影响,但这类组织对B+级钢的力学性能没有显著影响.试验还表明通过在正火处理前施加1次高温退火可以消除该类异常组织.

The influence of different pouring temperatures and Sr additions on the flowability of AlSi7Mg alloy is studied with a concentric triple helix device.Testing findings indicate that the flowability of the alloy increase dramatically with the increase of the pouring temperature.In terms of large sized thin - walled casting,a too low pouring temperature could result in a decrease of alloy fluidity and consequently casting defects,such as cold shuts and misrun.As the pouring temperature goes up,the tree - like crystalα-Al grows thicker and Si phase becomes aggregated,which is unfavorable to the alloy structure.A not too high pouring temperature,therefore,can improve the fluidity with the increase of Sr addition,although the improvement is not so much.