共查询到20条相似文献,搜索用时 687 毫秒
1.
2.
3.
4.
介绍了MKJ水冷灰铸铁排气管的铸件结构及技术要求,并详细阐述其生产工艺:覆砂铁型铸造,采用带有过滤网和集渣包的半开放式浇注系统;型腔覆砂层为8~10 mm;在砂芯中安放芯骨,芯头以相连的方式来加强砂芯结构强度;孕育剂为75%的SiCaBa+25%的75SiFe,包内加入,加入量为0.4%,处理温度为1 500~1 515℃,浇注温度为1 410~1 440℃。最终生产的MKJ排气管无裂纹、漏气等现象发生;金相组织为:石墨全部为A型,石墨长度为4级,基体组织为95%的珠光体;抗拉强度为275 MPa,硬度为202 HB。 相似文献
5.
6.
研究了水基涂料和环境湿度对三乙胺法冷芯盒砂芯强度的影响,并利用扫描电镜分析了砂芯断口。结果表明:(1)水基涂料使砂芯24h终强度显著下降,下降幅度随树脂加入量的增加而减少;存放1~6h后浸涂的砂芯强度低于即时浸涂强度和24h浸涂的砂芯强度。(2)在常温高湿环境下,随着砂芯存放时间的延长,砂芯强度出现显著的下降;在40℃、RH100%的环境下,砂芯的强度在5h达到最大值,随后砂芯的强度随放置时间的延长迅速下降。(3)低湿环境树脂粘结桥断口为以内聚断裂为主的复合断裂;而高湿环境里存放的砂芯,水分使树脂粘结桥出现裂纹、砂芯呈附着断裂。 相似文献
7.
8.
9.
《铸造》2015,(8)
以磷酸和氧化锌为主要原材料,合成了一种锌基磷酸盐粘结剂,通过加热硬化,可获得较高的强度,但吸湿性很强。因此,采用氧化镁、氢氧化钙和D剂进行了复合改性,取得了良好的效果。本文以砂芯的抗拉强度为考核指标,通过正交试验优化了各组分的比例,即磷酸溶液∶氧化锌∶氧化镁∶氢氧化钙∶D剂=200∶52∶3∶1∶8。在粘结剂加入量3%的情况下,得到砂芯的初始抗拉强度为3.03 MPa,抗吸湿性也得到明显的改善。在湿度30%~40%环境下,24 h抗拉强度为2.53 MPa;在湿度60%~70%环境下,24 h抗拉强度为1.64 MPa;发气量(850℃×3 min)为10.5 m L/g,高温残留强度(800℃×30 min)为0.12 MPa,能够满足一般铸造生产的要求。 相似文献
10.
《特种铸造及有色合金》2016,(6)
采用电阻炉熔炼了Al-7.2Zn-2.2Mg-1.8Cu-0.2Zr和Al-7.2Zn-2.2Mg-1.8Cu-0.2Sc-0.2Zr两种铝合金,在700~720℃挤压铸造成形,并经过465℃×24h+475℃×8h水淬+120℃×24h时效热处理。结果表明,Sc、Zr的复合添加能明显细化α-Al基体和晶间第二相;通过多级固溶和时效处理,显著提高了合金的力学性能,铸件的抗拉强度达到613MPa,屈服强度达到528 MPa,伸长率为6%。 相似文献
11.
介绍发动机缸体、缸盖铸件生产的总体工艺路线.目前大多数汽车发动机铸件生产企业都采用冲天炉-电炉双联熔炼,为防止铁液晶核减少、过冷度增加、白口化倾向较大,应控制电炉熔炼温度,避免长时间过热和保温;为确保铸件尺寸精度,铸型宜采用高密度造型,也可以采用呋喃树脂砂型或PEP-SET树脂砂型.根据国内目前情况,建议主体砂芯采用冷芯工艺,而水套等部位的砂芯采用覆膜砂工艺更为稳妥可靠. 相似文献
12.
介绍了采用AM60B镁合金和液态挤压铸造技术成形摩托车轮毂,对该铸件的成形工艺进行了试验并加以分析。结果表明,铸型温度为240~280℃,浇注温度为680~700℃,反挤压比压为82~100MPa,保压时间为20~25s、充型速度为0.91m/s时,反挤压铸造AM60B合金的力学性能达到:σb=218~227MPa,硬度(HBS)为66~71,δ5=9.8%~10.7%,αk=(17.5~18.7)×104J/m2。 相似文献
13.
热型连铸准单晶铜杆的工艺及性能 总被引:2,自引:0,他引:2
利用现有的水平连铸设备,改冷铸型为加热铸型,并在此基础上对电解铜(纯度99.95%)进行了水平连铸试验。在纯铜热型连铸过程中,当铸型出口温度为1135℃、拉铸速度为74mm/s、冷却距离为20mm时,能够拉铸出准单晶铜棒材。试验后对准单晶铜的电阻率和力学性能进行了测试分析,结果表明:与国家标准纯铜线T2M相比,准单晶铜的电阻率与国家标准相当;准单晶铜的抗拉强度与国家标准相比降低了26.6%,伸长率最大增加了76%。因此,准单晶铜具有较优异的塑性加工性能和较低电阻率,并且生产率较高。 相似文献
14.
介绍铸态QT850-3曲轴的生产工艺.采用低磷、硫炉料,感应炉熔炼,加入(质量分数)0.3%铜和0.02%锑进行合金化,并采用随流孕育强化孕育效果.为提高铸件致密度和尺寸精度,采用覆砂铁型铸造工艺.从曲轴不同部位取样测试性能结果,抗拉强度和伸长率分别都超过850 MPa和3%.曲轴样品已通过运转试验,情况良好. 相似文献
15.
采用砂型铸造AlSi7Cu2Mg铝合金阶梯形铸件,对不同部位试样进行等静处理,研究了不同热等静压压力(80~120 MPa)、时间(1~3h)对不同壁厚铸件缺陷及性能的影响。结果表明,随着热等静压压力增大和保压时间延长,不同壁厚铸件孔洞减少、密度提升,抗拉强度相应增大。铸件壁厚越大,密度和抗拉强度提升越明显;在热等静压温度(490℃)、压力(100 MPa)不变条件下,保温时间超过2h,铸件密度增加幅度较小;而在热等静压温度(490℃)、时间(2h)不变条件下,当热等静压压力超过临界值(100MPa)后,铸件抗拉强度提升不明显。 相似文献
16.
水平连铸直接复合成形铜包铝复合材料的组织与性能 总被引:1,自引:0,他引:1
研究了水平连铸直接复合成形铜包铝棒材的制备工艺和组织性能及退火处理对界面层塑性的影响。结果表明,采用水平连铸直接复合成形法在芯管长度L=210mm、铜铸造温度tCu=1230℃、铝铸造温度tAl=770~850℃、一次冷却水流量Q1=600L/h、二次冷却水流量Q2=600~800L/h、平均拉坯速度v=60~87mm/min的可行工艺窗口下能够制备出直径为30mm、铜包覆层厚度为3mm、质量良好的铜包铝复合棒材。在退火温度为530℃、保温时间为50min的工艺条件下,退火处理后可明显改善界面层的塑性。铜包铝复合棒材的抗拉强度和伸长率分别为80~94MPa和18%~31%。 相似文献
17.
Homogeneous melting without any nuclei was performed using the cold copper nozzle arc casting furnace and ladle arc-melt type furnace. Casting of a bulk glassy alloy can be achieved by using a copper nozzle arc casting furnace, which eliminates nucleation site (cold spot) for crystallization. Besides, the pouring molten alloy was melted homogeneously by arc heating before casting into the mold, similar to a pseudo float melting state. To produce a bulk glassy alloy sheet, a combination of the ladle arc-melt type furnace and squeeze cast method was used. Using this method, we succeeded in producing Zr50Cu30Ni10Al10 bulk glassy alloys in a rod shape by the former method and in a sheet form by the later method. Tensile strength of the Zr50Cu30Ni10Al10 bulk glassy alloy sheet is about 1900 MPa and the plasticity of the alloy at room temperature is significantly improved by cold rolling. 相似文献
18.
Jun Zhao Zhi-yong Zhang Shi-bing Liu Kun Shi Chun-ling Bao Zhao-sheng Ning Ping Yan Lei Wang Yan-chun Lou 《中国铸造》2020,(1):29-34
Casting technology of thin-wall TiAl alloy turbochargers was studied by investment casting and numerical simulation.Misruns and gas holes were the main defects observed in preliminary work due to the poor fluidity of alloy,and to gas entrapment.In order to eliminate these defects,cast parameters,such as centrifugal rotation rate and mould preheating temperature,were optimized by numerical simulation,meanwhile,the structure of the shell mould was optimized to improve the filling capacity of TiAl alloy.Pouring experiments were carried out by vacuum induction melting furnace equipped with a water-cooled copper crucible based on the above optimization.The quality of the TiAl alloy casting was analyzed by fluorescent penetrant inspection and X-ray detection.The results show that a centrifugal rotation rate of 200 rpm,mould preheating temperature of 600°C,shell preparation through organic fiber addition can dramatically improve the mould filling capacity,and integrated turbochargers were finally prepared. 相似文献
19.
介绍了840缸盖的铸件结构及技术要求,详细阐述了铸造工艺方案:采取平浇的方式,压边冒口进铁液,浇口比为ΣF直:ΣF横:ΣF内=2:2.3:1,一箱4件造型,水套芯与油嘴孔芯使用热芯盒制芯,其余的砂芯均使用冷芯盒制芯;利用ABP中频电炉熔炼,出铁温度1 455℃,出铁时进行随流孕育和引爆法蠕化,使用75SiFe孕育剂,出铁时孕育量为0.2%~0.3%,二次孕育的孕育量为0.4%,蠕化剂使用REMg和RESiFe,加入量分别为0.2%±0.05%和0.3%±0.05%。浇注温度1 415±10℃,浇注时间18±2 s。最终得到的铸件内外表面清洁、无披缝、粘砂、气孔、裂纹等问题,表面粗糙度小于Rz100,气道粗糙度小于Rz80;铸件蠕化率达到55%~75%,试棒抗拉强度380~430 MPa,缸盖进、排气道间底面硬度180~195 HB,珠光体体积分数20%~40%。 相似文献
20.
An orthogonal test was conducted to investigate the influence of technical parameters of squeeze casting on the strength and ductility of AlSi9Cu3 alloys. The experimental results showed that when the forming pressure was higher than 65 MPa, the strength (σb) of AlSi9Cu3 alloys decreased with the forming pressure and pouring temperature increasing, whereas σb increased with the increase of filling velocity and mould preheating temperature. The ductility (δ) by alloy was improved by increasing the forming pressure and filling velocity, but decreased with pouring temperature increasing. When the mould preheating temperature increased, the ductility increased first, and then decreased. Under the optimized parameters of pouring temperature 730 °C, forming pressure 75 MPa, filling velocity 0.50 m/s, and mould preheating temperature 220 °C, the tensile strength, elongation, and hardness of AlSi9Cu3 alloys obtained in squeeze casting were improved by 16.7%, 9.1%, and 10.1%, respectively, as compared with those of sand castings. 相似文献