共查询到20条相似文献,搜索用时 140 毫秒
1.
2.
随流孕育是铸态球铁生产中极重要的一环。国外已就随流孕育剂作了大量的研究,研制出适合不同情况下使用的孕育剂品种。本文就高效复合孕育剂SRCB生产铸态铁索体球铁件中的作用作一些探讨。我厂属大量流水线生产,球铁件均进行随流孕育。孕育设备为螺旋给料器,孕育剂加入量为0.15%,孕育剂成分(%)为:St55~65,REI~4,Ca3~8,助熔剂10%左右,余为铁。经过近三年的应用,情况良好。1.SRCB孕育剂和75SIFe对比试验我们在处理同一包铁水时(800k8)分别用SRCB和75SIFe作随流孕育,浇注阶梯试决(见图1)及机械性能试块,对… 相似文献
3.
研究了碳化硅对球铁凝固组织的影响。结果表明:用碳化硅对原铁水进行处理具有显著减少无后孕育球铁的白口倾向及消除反白口的作用;后孕育有很强的减白口能力;经后孕育处理的球铁,碳化硅的作用减小。 相似文献
4.
水冷金属型离心铸造球墨铸铁管金相组织和力学性能的控制 总被引:1,自引:0,他引:1
在总结长期生产实践经验的基础上,通过采用优质高炉铁水,调频电炉升温和调整成分,低稀土硅钡镁钙球化剂包内球化,二次孕育处理(Fe-Si75包内一次孕育,硅钡钙复合孕育剂随流二次孕育),型内覆粉孕育(三次孕育),控制金属型冷却水进、出型温度及连续退火规范,形成了能稳定地获得金相组织适宜、力学性能符合ISO2531-91要求的各种口径球铁管离心铸造成套工艺,并对工艺参数与金相组织和力学性能的关系进行了分析 相似文献
5.
固定生铁(低硅:1.25%-1.65%Si)来源,采用高碳当量(CE=4.3%-4.9%),高铁水出炉温度(1420℃-1460℃),采取浇包孕育,铁水槽孕育相结合的一次大剂量孕育工艺。10年来生产的3200吨球铸件,合格率在98%以上。 相似文献
6.
固定生铁(低硅:125%~165%Si)来源,采用高碳当量(CE=43%~49%)、高铁水出炉温度(1420℃~1460℃),采取浇包孕育、铁水槽孕育相结合的一次大剂量孕育工艺。10年来生产的3200吨球铁件,合格率在98%以上。 相似文献
7.
我厂机床铸件与国外同行相比存在以下几个方面的问题:(1)破当量相同时,强度比国外约低一个牌号;(2)铸件壁厚大,机床比国外重10%;(3)残余应力大,机床精度低;(4)耐磨性差,寿命低。针对以上问题,我们用WH一五型孕育覆盖剂孕育铁水的方法来获得高强度灰铸铁,基本满足了生产的需要,并有效地解决了一些问题。1二WH一工孕育覆盖剂WH一互孕育覆盖剂是由孕育剂和覆盖剂两部分组成,它能将孕育、覆盖二工序合并处理完成,其化学成分(%)为;of.5~2.0,St15。17,REI.5。2.5,Ca6.0。6.4,AI0.4。0.7,Ti0.5、1… 相似文献
8.
讨论了生产铸态珠光体球铁几个工艺参数的影响。证实:Cu合金化有较好的综合机械性能:Sb,Cr合金化成本较低,也能保证机械强度;Sb以孕育方式使用有较大优越性,铸态球光体球铁生产应用较低硅量,对缩孔没有决定性的影响,粉状SiCa用于随流孕育可提高孕育效果。 相似文献
9.
1孕育机理的文献综述(1)喜多清.铸锻造(日),1994;47(8):39~43综述了有关孕育的作用机理的文献,并研讨之。显示了如下机理。叙述了(豆)关于铁水的石墨化与氧有关,SIO。那样的非金属夹杂物是石墨的核心说;(2)非晶质SIO。不能成为核心,卜方英石是核心说;(3)来自孕育剂的硅产生局部的高硅浓度,促进初晶石墨析出说等说法。参222热循环使用初期钢锭模和底盘铸铁性能的变化Cape6llonAMetal.113neerunBucm·yH的出决。风HH。[。lqepl。。MIT——。,p,。。(俄),1994;(5):72~74研究了从室温至1000℃的温度… 相似文献
10.
介绍与冲天炉熔炼有关的几个问题的处理方法,包括:(1)如何防止熔化带以上耐火砖容易掉落;(2)如何防止过桥、出铁口易被侵蚀;(3)固定式前炉容量大小的选择;(4)如何保持浇包尺寸;(5)加料口材料选择:(6)要否使用热风炉胆;(7)孕育处理方法与孕育量;(8)灰铸铁的含硫量;(9)风口比。 相似文献
11.
《中国铸造》2016,(5):352-360
To find the optimized levels of various casting parameters in the ductile iron casting, various casting defects and the rejection rate were observed from a medium scale foundry. The controlled values of different casting parameters such as pouring temperature, inoculation, carbon equivalent, moisture content, green compression strength, permeability and mould hardness were selected. Three different melts of metal with 0.4wt.%, 0.6wt.%, and 0.8wt.% inoculation(Fe-Si-Mg alloy and post inoculant) were produced using a 1-ton capacity coreless medium frequency induction furnace. L-27 orthogonal array with 3-level settings were chosen for the analysis. Responses for each run were observed. The signal-to-noise(S/N) ratio for each run was calculated using the Taguchi approach, and the optimized levels of different casting parameters were identified based on the S/N ratio. The analysis of variance for the casting acceptance percentage concludes that inoculation is the most significant factor affecting the castings' quality with a contribution percentage of 44%; an increase in inoculation results in a significant improvement in acceptance percentage of ductile iron castings. The experiment results showed that with the optimized parameters, the rejection rate was reduced from 16.98% to 6.07%. 相似文献
12.
《International Journal of Cast Metals Research》2013,26(1-4):7-10
AbstractInoculation of cast iron has been mainly studied for the nucleus materials and the development of new inoculants. The effect is widely recognised; nevertheless, the mechanism was not fully understood. Inoculation leads to a decrease in chill depth, depressed the formation of D type graphite to form A type graphite and increase in the eutectic cell number. The transition from A type to the D type graphite is also accelerated by Ti addition; therefore we used Ti added samples for the study of D type graphite formation. The increase in the eutectic cell number produces a decrease in the cell size, namely the radius; nevertheless, the solidification time of the castings does not change by inoculation. Therefore, the solidification rate of the cell, namely the linear solidification rate, should decrease with inoculation and the decrease produces a depression in the chill and D type graphite due to the smaller undercooling. Therefore, we have to consider the three-dimensional solidification rate for discussing the cooling curve. 相似文献
13.
HT300高强度缸体缸盖材料熔炼技术研究 总被引:4,自引:0,他引:4
分析了熔炼工艺、碳硅成分、锰硫成分、合金化及孕育处理对高强度灰铸铁铁液质量的影响,认为大量使用生铁使铁液收缩倾向增大且使铸件性能降低;增碳剂的选用是全废钢熔炼的关键;在较高碳硅含量条件下生产高强度灰铸铁件,必须设法在熔炼过程中增加石墨晶核,并增硫防止石墨长成粗大片状;适当的合金化和孕育处理,可以使铁液的收缩倾向得到明显改善。指出可以通过延迟开箱时间使铸件在砂箱中缓慢冷却以消除铸造应力,为生产优质铸件提供最后保证。 相似文献
14.
分析了熔炼工艺、碳硅成分、锰硫成分、合金化及孕育处理对高强度灰铸铁铁液质量的影响,认为大量使用生铁使铁液收缩倾向增大且使铸件性能降低;增碳剂的选用是全废钢熔炼的关键;在较高碳硅含量条件下生产高强度灰铸铁件,必须设法在熔炼过程中增加石墨晶核,并增硫防止石墨长成粗大片状;适当的合金化和孕育处理,可以使铁液的收缩倾向得到明显改善。指出可以通过延迟开箱时间使铸件在砂箱中缓慢冷却以消除铸造应力,为生产优质铸件提供最后保证。 相似文献
15.
16.
研究了压力成型孕育块的熔解特性及孕育剂组成。结果表明,在75硅铁孕育块含有适量的Bi和冰晶石并具有合适的形状时,可以减小孕育滞后,提高孕育均匀性,满足生产薄壁铸态铁素体球墨铸铁件的孕育要求。 相似文献
17.
The combined effects of direct current pulsed magnetic field (DC-PMF) and inoculation on pure aluminum were investigated, the grain refinement behavior of DC-PMF and inoculation was discussed. The experimental results indicate that the solidification micro structure of pure aluminum can be greatly refined under DC-PMF. Refinement of pure aluminum is attributed to electromagnetic undercooling and forced convection caused by DC-PMF. With single DC-PMF, the grain size in the equiaxed zone is uneven. However, under DC-PMF, by adding 0.05% (mass fraction) Al–5Ti–B, the grain size of the sample is smaller, and the size distribution is more uniform than that of single DC-PMF. Furthermore, under the combination of DC-PMF and inoculation, with the increase of output current, the grain size is further reduced. When the output current increases to 100 A, the average grain size can decrease to 113 μm. 相似文献
18.
郭向南 《中国铸造装备与技术》2014,(1):39-42
阐述了风电球墨铸铁球墨形核、生长原理与孕育、球化处理的关系。石墨的形核分为均匀形核和异质形核,形核物质与石墨的失配度要小于12%是孕育处理和孕育剂选用的理论基础,孕育处理可以有效增加石墨核心数,孕育以邻近浇注为原则,且采用多次孕育法。球墨的生长必须有强烈的过冷以满足球墨缺陷生长的条件,介绍了提高铁液过冷度的主要方法——球化处理法,介绍了球化剂的选择和使用方法。 相似文献
19.
采用炉前包冲内冲废钢与孕育相结合的方法,研究了炉前包内冲废钢对灰铸铁组织和强度的影响。结果表明:冲废钢可以增加灰铸铁中初生奥氏体的数量,改变初生奥氏体枝晶的分布形态,强化灰铸铁孕育效果,有利于提高灰铸铁的强度。 相似文献
20.
《Intermetallics》2014
Ductile crystalline phases of bcc Ta and CuZr(B2) were coupled in situ and assembled in a core–shell structure in bulk metallic glass (BMG) composites through controlled inoculation. These two phases were dispersed homogeneously within the amorphous matrix. The CuZr(B2) phase nucleated preferentially on the bcc Ta surface following well-defined crystallographic orientation relationships. A layer of intermediate transition zone containing interwoven amorphous structures formed at their interfaces to lower the interfacial energy. The composites exhibited significantly improved plasticity and simultaneous increase in strength. This study greatly aids in the microstructural design and tailoring for optimized mechanical properties of BMG composites. 相似文献