铸态铁素体低碳球墨铸铁的研究

对铸态铁素体低碳球墨铸铁进行了研究.试验中所选择低碳球墨铸铁的化学成分为:1.2%～2.2%C,2.8%Si,＜0.4%Mn,＜0.05%P,＜0.04%S.铁液采用无芯感应电炉熔炼后,铁液的出炉温度控制在1480～1550℃之间,经过主要由某些公认的反球化元素组成的Sx变质剂进行一次性变质处理.本文分析了铁液的化学成分、变质剂的种类和加入量对铸态铁素体低碳球墨铸铁形成的影响.试验的结果表明:当C1.2%～1.8%,Sx1变质剂的加入量为0.8%或1.0%,可以得到球状石墨 珠光体 少量铁素体组织,Sx1加入量为1.2%,基体中无球状石墨,而且随着含碳量和变质加入量的提高铁素体数量基本不变.当C2.0%～2.2%,Sx1和Sx2变质剂都不能使石墨球化,Sx3变质剂加入量为0.8%,石墨被部分球化;Sx3加入量为1.2%,基体中无球状石墨,Sx3入量为1.0%,可以得到球化良好,铁素体数量大于85%和少量珠光体组织的低碳球墨铸铁,其机械性能主要为:σb≈400MPa、δ≈15%、αk≈22J/cm2,HB≈200.     

稀土球化剂如何正确用于球墨铸铁的生产

稀土变质剂在球墨铸铁中能起到促进石墨成球状、改良石墨形状、降低残余镁量、脱氧脱硫、消除干扰元素和减少夹杂的作用.稀土中铈与硫结合能促进基体石墨核心的形成,增加石墨球数.但是在生产中如何利用稀土球化剂来保证球墨铸铁的质量仍是非常重要的问题.     

低碳球墨铸铁

研究了ＳＸ变质剂对低碳铁水的影响。结果表明，用含碳量为１．６～２．２％的超亚共晶低碳铁水，不加任何合镁或稀土之类的球化剂，只须加入少量ＳＸ变质剂对铁水进行变质处理，即可在铸态下获得石墨球细小、圆整、分布均匀，且有较高综合力学性能的低碳球墨铸铁     

低碳球铁的系列化及其应用研究

对低碳球铁中不同种类Sx变质剂的制作工艺和组成进行了研究,对低碳球铁的系列化进行了探讨.研究表明,通过准铸态贝氏体工艺,并利用Sx-2型变质剂对Si-Mn-Cr-Cu低合金化的低碳铁液进行处理,可使低碳球铁稳定获得以针状无碳贝氏体为主,并有一定比例(25%～28%)奥氏体的准铸态贝氏体低碳球铁;含碳≤ 2%的Ni-Si-Cr35 5 2低碳铁液,经Sx-3型变质剂的变质处理,可获得球化良好的奥氏体耐热耐蚀低碳球铁;含2.0%C,2.8%Si的低碳铁液经过Sx-4型变质剂变质处理后,能够在铸态下获得石墨球圆整、金属基体中铁素体比例达85%以上,δ≥10%的高韧塑性铁素体低碳球墨铸铁.     

复合稀土球化剂对球铁石墨形态和球数的影响

研究了两种球化剂及其加入量对球墨铸铁石墨形态和球数的影响,分析了复合稀土的作用机理。结果表明:含有稀土元素的球化剂加入量为1.5%时,铸态组织中形成了大量的蠕虫状石墨;加入量为1.8%时球化良好,同时球状石墨数量达到极值,圆整度高;继续增加球化剂加入量对于提高石墨球数没有明显作用,当加入量达到2.2%时局部区域出现了变态石墨。与单独加入镁球化剂相比,含RE等元素的球化剂使石墨球数增加,圆整度提高,石墨球平均直径减小。EDX分析表明石墨球中心富集了S、Y、Mg、Ca、Ce等元素,并可作为石墨形核的有效基底。     

RE-Mg对高铬白口铸铁性能和组织的影响

采用超景深显微镜、扫描电镜和X射线衍射仪研究了由镧、钇、镁组成的复合变质剂对含有多种合金元素的高铬白口铸铁性能和组织的影响。研究结果表明:复合变质剂对合金组织中菊花状碳化物、柱状树枝晶、马氏体含量以及力学性能都有影响。当变质剂的加入量为0.3%时,碳化物和基体的粒度达到最小;当变质剂的加入量为0.6%时,碳化物的分布形态最为理想,此时的冲击韧度和硬度都达到了最优值,分别为:5.7 J/cm2和HRC51.14。     

低碳球墨铸铁中SX变质剂的行为分析

研究了低碳球墨铸铁中石墨球的球化机制，并从“气泡”、“核心”两个方面探讨了ＳＸ变质剂中表面活性元素的作用的影响。结果表明，ＳＸ变质剂中的表面活性元素可从三个方面促使石墨在成为球状，一是低沸点元素在高温水中形成气泡；二是在非金属夹杂物界面上选择吸附，使夹杂物表面棱角钝公接近球形。三是使石墨／铁水界的界面能降低，促使石墨球形核长大。     

w（Si）、w（C）量及冷却速度对铸态球铁组织的影响

用热分析法研究了w（Si）、w（C）量和冷却速度对球铁中石墨和基体组织的影响。结果表明：适量增加孕育剂加入量能缩短球铁凝固过程中共晶平台的宽度,有限减少或避免石墨的畸变;在孕育剂加入量为1.38%时,能够得到66.8%的铁素体含量且球化效果良好的球墨铸铁;在w（C）量为3.94%、w（Si）量为2.23%时,由于CE达4.9%,导致与石墨漂浮相关的开花状石墨和枝晶石墨产生。     

原料遗传性对球墨铸铁显微组织的影响

采用不同配比的生铁和废钢,通过硅铁及电极石墨增碳剂的调节,在相同铸造工艺下,制成化学成分基本相同的球墨铸铁,并对试样的显微组织进行了分析.结果表明,原料的遗传性对球铁石墨球的形态、大小、分布以及球铁的基体组织存在明显的影响.     

炉前处理工艺对ADI阻尼性能的影响

采用控制变量的方法,分别测试不同炉前处理工艺参数(一次孕育剂的加入量、二次孕育剂的加入量以及球化剂的加入量)下ADI试样的阻尼性能,并对相应的金相组织进行观察和分析,探究合理的炉前处理工艺参数。结果表明,加入1.0%~1.4%的一次孕育剂,随着一次孕育剂的增加,组织中石墨球的数量增加,ADI的阻尼性能升高。二次孕育剂的加入量为0.2%左右时,ADI组织中的石墨球显得更加圆整,大小及分布均匀,ADI的阻尼性能最佳。球化剂加入量为1.1%~1.5%时,ADI试样表现出优异的阻尼性能,高于或者低于这个加入量范围都会降低ADI的阻尼性能,并且恶化ADI组织。     

Cast iron-a predictable material

High strength compacted graphite iron (CGI) or alloyed cast iron components are substituting previously used non-ferrous castings in automotive power train applications.The mechanical engineering industry has recognized the value in substituting forged or welded structures with stiff and light-weight cast iron castings.New products such as wind turbines have opened new markets for an entire suite of highly reliable ductile iron cast components.During the last 20 years,casting process simulation has developed from predicting hot spots and solidification to an integral assessment tool for foundries for the entire manufacturing route of castings.The support of the feeding related layout of the casting is still one of the most important duties for casting process simulation.Depending on the alloy poured,different feeding behaviors and self-feeding capabilities need to be considered to provide a defect free casting.Therefore,it is not enough to base the prediction of shrinkage defects solely on hot spots derived from temperature fields.To be able to quantitatively predict these defects,solidification simulation had to be combined with density and mass transport calculations,in order to evaluate the impact of the solidification morphology on the feeding behavior as well as to consider alloy dependent feeding ranges.For cast iron foundries,the use of casting process simulation has become an important instrument to predict the robustness and reliability of their processes,especially since the influence of alloying elements,melting practice and metallurgy need to be considered to quantify the special shrinkage and solidification behavior of cast iron.This allows the prediction of local structures,phases and ultimately the local mechanical properties of cast irons,to asses casting quality in the foundry but also to make use of this quantitative information during design of the casting.Casting quality issues related to thermally driven stresses in castings are also gaining increasing attention.State-of-the-art tools allow the prediction of residual stresses and iron casting distortion quantitatively.Cracks in castings can be assessed,as well as the reduction of casting stresses during heat treatment.As the property requirements for cast iron as a material in design strongly increase,new alloys and materials such as ADI might become more attractive,where latest software developments allow the modeling of the required heat treatment.Phases can be predicted and parametric studies can be performed to optimize the alloy dependent heat treatment conditions during austenitization,quenching and ausferritization.All this quantitative information about the material’s performance is most valuable if it can be used during casting design.The transfer of local properties into the designer’s world,to predict fatigue and durability as a function of the entire manufacturing route,will increase the trust in this old but highly innovative material and will open new opportunities for cast iron in the future.The paper will give an overview on current capabilities to quantitatively predict cast iron specific defects and casting performance and will highlight latest developments in modeling the manufacture of cast iron and ADI as well as the prediction of iron casting stresses.     

多元高铬铸铁在介质固液泵上的应用研究

以高铬铸铁为基础并加人多种少量和微量合金，开发研制出多元高铬铸铁的过流部件，其抗磨效果得到提高，并具有良好的综合力学性能，达到了使用条件要求。寿命比原产品提高了2倍以上，且安全可靠。     

EQUILIBRATING PARTITION RATIOS OFNb,Mn AND Si BETWEEN LIQUID IRON AND MgO-SiO_2-MnO SLAG MELTS

The liquid iron containing elements Nb,Mn and Si has been equilibratedwith MgO-SiO_2-MnO slag melts at 1600℃ in a Mo wire-wound resistance furnace with aduration of 4h.The oxygen activities in liquid iron were measured with oxygen sensors.Usingthe known equilibrium constants of concerning reactions and the oxygen activities in liquidiron,the activities of components in the slag melts can be calculated.It was found that the par-tition ratios of Nb.Mn and Si have a close linear relationship with α_(FeO) in logarithmicscale.The dependence of Nb partition ratio on mole fractions of the slag components was al-so obtained.     

Zementmörtelauskleidungen von Trinkwasserleitungsrohren aus Guss und Stahl

Cement mortar linings in drinking water pipes made of steel and ductile iron For more than 100 years cement mortar has been used as internal corrosion protection for water pipes of steel and ductile iron. The combination of these 2 components has proved to be a perfect solution – not only regarding the physical and mechanical aspects, also with respect to the corrosion chemical side for pipelines and construction pipes. This report gives a survey on questions that are often discussed in practical use concerning the possibilities and limits for the use of cement mortar linings in the drinking water area.     

Electric arc deposition of carbon steel coatings with improved mechanical properties

To achieve high deposition rate and efficiency, electric arc spraying has been routinely used to deposit carbon steel coatings. Although retention of carbon in these coatings is poor due to the use of compressed air during spraying, the coatings are sufficiently hardened by brittle iron oxide inclusions to be suitable for hardfacing mechanical components used in mild adhesive and abrasive wear environments. However, carbon steel coatings can be employed for hardfacing mechanical components used in more aggressive wear environments, provided they are hardened by the carbon retention rather than by iron oxide inclu-sions. Therefore, to increase retention of carbon, reduce inclusion of iron oxides, and improve hardness and wear properties of carbon steel coatings, deposition experiments were carried out using an inexpen-sive nitrogen, which is produced on-site by a pressure swing adsorption or a membrane separation sys-tem, instead of compressed air during spraying.     

对铸件的力学性能提供合格保障的质保技术

论述一种对铸件的力学性能提供合格保障的质保技术,其实现方法包括：通过快速化学分析,分析铁水、钢水、铝水、或铜水的成分。并根据指令炉前的配料和熔化程序进行不断调整。通过快速金相分析,将铸件的金相组织数据指令发给浇铸程序,以免不合格的铁水、钢水、铝水或铜水浇铸成铸件。该质保技术同时保证化学成份和金相组织数据合格,从而保证铸件的力学性能和最终质量。实现了铸件生产的全程超前、预警和指挥,从而提供了一种全面保障了铁水、钢水、铝水、或铜水浇成铸件的内在质量。四平联合收割机总厂铸钢车间、铸钢车间对ZG45、ZGMn13、ZG40Gr及HT200、HT250、QT60-2等钢铁品种进行质保实践,对E514及东风5联合收割机28种铸件,检测单件力学性能合格率达98%以上。     

低铬白口耐磨铸铁组织和性能的研究

采用金属型浇注不同成分的铬系白口铸铁磨球,研究化学成分、热处理工艺对铸铁微观组织,冲击韧性和硬度的影响。结果表明：含Cr量为3.231%、含C量为4.920%的白口铸铁,经过950℃淬火处理＋300℃回火处理能够获得良好的韧性与硬度的结合;随着含碳量增高,铸铁的硬度升高,冲击韧性下降;而随着回火温度增高,硬度将降低,冲击韧性提高。     

球墨铸铁零件的低温热处理工艺研究

本文研究了热处理工艺对球墨铸铁力学性能的影响。结果表明,低温热处理（725℃正火或球化退火）能保证球墨铸铁零件具有一定的综合力学性能和良好的工艺性能。     

Static and low‐cycle strength of welded joints in a low‐alloy steel on the mesoscale level

The publications concerned with the pressure welding of cast iron are analysed. The advantages and shortcomings of individual welding methods are discussed. Examples of welding components and sections made of cast iron and of dissimilar components produced from steel and cast iron are shown. The current state of pressure welding of cast iron and prospects for the further development of this technology are outlined.     

ACTIVITY OF MnO IN LIQUID BLAST-FURNACE-TYPE SLAGS AND ITS RATE OF REDUCTION

本文报告了锰在银、铁,渣、铁及渣、银间的分配数据及高炉型渣中MnO活度的计算结果。从熔渣结构观点讨论了碱度,Al_2O_3,MgO及CaF_2对渣中MnO活度的影响。还报告了渣中MnO还原速率的测定结果,讨论了反应级数问题。最后,对实验结果在生产实际中的应用进行了讨论.