磷硼蠕墨铸铁压榨辊的铸造生产

通过介绍磷硼蠕墨铸铁压榨辊的生产工艺过程，论述了蠕墨铸铁压榨辊优于普通灰口铸铁压榨辊的理论依据及磷硼蠕墨铸铁压榨辊的生产原理。     

硼磷铜钛铸铁气缸套的研制

本文介绍了硐磷铜铁铸铁气缸套的研制情况，探讨了其耐磨机理，并用金相、化学成份、硬度、快速模拟磨损试验进行了分析。研制试验结果表明：硼磷铜铁铸铁气缸套比硼铸铁气缸套的耐磨性提高29．8％，比磷铜铁铸铁气缸套的耐磨性提高91．5％，硼磷铜钦铸铁气缸套成本低、耐磨性高，具有较高的企业经济效益和牡会效益，有推广价值。     

稀土蠕化剂对蠕墨铸铁生产的影响

目前对稀土元素在蠕墨铸铁中的应用已经有了较深的研究,但是不少人忽略了这样一个问题：稀土不是一种元素,而是一系列元素的总称,稀土中不同元素对蠕墨铸铁生产的影响不同。本文通过生产实践中遇到的问题来说明稀土中镧和铈的量对蠕墨铸铁生产的质量影响。     

蠕墨铸铁闸瓦材料组织性能研究

利用冲天炉铁水,通过包底孕育蠕化处理,成功地浇铸出蠕墨铸铁材料。金相观察表明：用2．0％稀土钙铝硅铁合金及2．0％稀土镁铝锌硅铁含金蠕化处理的铸铁,其石墨呈细小、均匀分布的蠕虫状。蠕墨铸铁冲击断口显示,基体发生了较大的塑性变形,且具有较高的冲击功。用蠕墨铸铁制成的机车闸瓦具有比普通灰铸铁闸瓦高得多的压断强度,是制造机车闸瓦的理想材料,值得推广应用。     

蠕墨合金铸铁活塞环材料研发

本文介绍了作者研制的蠕墨合金铸铁活塞环材料,从材料性能、铸造工艺、过程控制、成本分析进行了论述,蠕墨合金铸铁铸造工艺范围比较窄,活塞环又是小、薄铸件,给稳定生产带来很大困难.作者通过试验,现在已可以稳定批量生产蠕墨合金铸铁活塞环。     

PCBN超硬刀具加工蠕墨铸铁的切削性能研究

蠕墨铸铁具有特有优势,包括良好的铸造性能、耐磨性和高强度等,但是,它也会引起普通合金刀具的磨损,导致刀具的使用时间较短。文章通过对收集的数据进行分析,旨在研究不同种类的PCBN超硬刀具在加工蠕墨铸铁过程中的切削性能,包括蠕墨铸铁切削力研究、切削温度研究、蠕墨铸铁刀具的磨损研究和蠕墨铸铁切削形成机理研究。     

稀土蠕墨铸铁

稀土蠕墨铸铁是一种以蠕虫状石墨为主的新型铸铁材料。它的机械-物理性能介于灰铸铁和球墨铸铁之间,不仅兼有两者的优点并有独特性,因而可对某些灰铸铁零件进行减薄壁厚、减轻重量的设计改革,节省铸件的金属材料。这种铸铁可加入合金元素使其合金化,从而获得某种特殊性能。自1965年我们开始研究和用冲天炉生产蠕墨铸铁以来,这种新型铸铁材料已被人们公认,尤其是七十年代以来,对它的应用已逐步在各个领域受     

用蠕墨铸铁生产气缸盖

高负荷发动机中,由于热交变负荷较大,气缸盖承受的应力,已进入疲劳强度范围。因此,事前必须估计到,气缸盖使用一定时间后,就会断裂而损坏,故而采用球铁或铸钢已属必要。但铸钢成本太高,且不能保证铸件的气密性,而球铁由于传热性能较差,也不理想;只有蠕墨铸铁较好,它和球铁和片墨合金铸铁相比,铸件缩松倾向较小。蠕铁的石墨介于片状和球状之间。按德国钢铁检验标准,蠕铁石墨应属P型,或相当于德国铸造协会(VDG)441号标准中订定的Ⅲ型。目前较保险的生产方法,可按Leoben/Breman-ger铸造所的专利法进行。该法的先决条件是采用低磷、低锰、低硫的生铁,加入的废铁量不得超过20％。生产球铁的孕育方法对蠕铁也能适用。铁水的处理(去     

蠕墨铸铁切削机理的探讨研究

为了推广蠕墨铸铁的应用领域和降低企业生产成本,改善蠕墨铸铁的切削加工具有重要意义。针对蠕墨铸铁难以切削加工的材料特性和目前改善蠕墨铸铁切削加工方法的局限性,提出改变蠕墨铸铁的化学成分以改善其切削加工的研究方法。通过往蠕墨铸铁中添加3个不同量的氮化硼化合物,用单因素实验方法测出氮化硼对蠕墨铸铁抗拉强度、硬度及耐磨特性的影响。实验结果表明,蠕墨铸铁中的氮化硼含量为0.0144%、0.0223%和0.0288%时,其抗拉强度和硬度没有改变;当氮化硼含量为0.0144%时,蠕墨铸铁与实验钢球组成的摩擦副的摩擦系数最小,为0.188。在不改变蠕墨铸铁的力学性能的前提下,往蠕墨铸铁中添加适量的氮化硼以改善其切削加工性能的研究方法具有可行性。     

RuT340蠕化质量的控制

我公司生产的蠕墨铸铁铸件主要以焦炉设备和钢锭模为主,重量1.5～2.5t,材质为RuT340,它是以珠光体为主的混合基体蠕墨铸铁。使用7t/h冷风冲天炉熔炼铁液,以往一直采用合金从出铁槽随流冲入,然后人工搅拌处理的蠕墨铸铁处理工艺,但是蠕化质量不稳定,蠕化率较低(60％左右)。主要原因是化学成分波动较大;蠕化剂品质     

铸铁气蚀破坏机制

从铸铁基体组织，石墨形态，合金元素等方面探讨铸铁气蚀性能的影响因素，分析空化的力学冲击作用与气蚀时的材料受力情况，研究铸铁气蚀裂纹核的形成与扩展乃至导致铸铁气蚀破坏的过程，剖析球墨铸铁的气蚀特点。     

影响灰铸铁致密性的主要因素的实验研究

本文采用自制致密性试验装置对影响灰铸铁致密性的主要因素进行试验研究。结果表明由石墨和裂纹构成的通道是产生渗漏的主要途径。改善石墨形态,在保证获得致密组织的前提下降低碳当量,加入适量合金元素铬、铜,增加冷却速度,有利于改善灰铸铁材质致密性。     

Corrosion and wear resistance characteristics of NiCr coating by laser alloying with powder feeding on grey iron liner

To reduce the mixed fuel induced excessive wear of the cast iron engine cylinder liners, research on laser alloying of NiCr alloy with powder feeding was performed to locally change both the composition and the microstructure of the liner. The research indicated that laser alloying of 75Ni25Cr on grey cast iron liner demonstrates sound alloying layers free of cracks and porosities. The microstructure of the alloyed layer is composed of pre-eutectic austenite and ledeburite. The alloying element Ni is mainly located in the austenite, while Cr is mainly in cementite. The average hardness is HV_0.2500. The corrosion resistance of the alloyed layers in diluted H₂SO₄ solution and NaOH solution is dramatically improved compared to the grey cast iron. The relative wear resistance of the laser-alloyed 75Ni25Cr layer is 4.34 times of that of the grey cast iron. The improvements on the corrosion and wear resistance of the cast iron are attributed to the composition and microstructure change by laser alloying of 75Ni25Cr. Laser alloying can be a good solution to improve wear and corrosion resistance of the grey iron liners in mixed fuel environment.     

合金元素对室温油分级等温淬火贝氏体球铁组织和性能的影响

采用一种新的室温油分级等温淬火工艺获得低合金贝氏体球墨铸铁;研究了硼、铜、锰对贝氏体球墨铸铁组织和性能的影响,并讨论了球墨铸铁的性能滞后现象,即等温淬火后随时问延长硬度增加的现象。结果表明：硼和锰能提高硬度,降低韧性;铜提高韧性。合理加入合金元素有利于提高贝氏体球铁的性能。贝氏体球墨铸铁有性能滞后现象,其实质是溶质类拖曳作用。     

PCBN刀具切削铸铁材料的研究进展

对PCBN刀具切削灰铸铁、球墨铸铁及蠕墨铸铁的研究进行了回顾和总结 ,并建议国内加强对PCBN刀具切削灰铸铁和蠕墨铸铁的研究     

Effect of structural features on erosion resistance of cast irons

Erosion resistance of four types of cast iron of different microstructures and graphite morphologies (viz., grey cast iron, compacted graphite iron, spheroidal graphite iron and austempered ductile iron) was evaluated in three different erosive media. Results indicate that austempered ductile iron has the highest erosion resistance in all three media, followed by spheroidal graphite iron, compacted graphite iron and grey cast iron, in that order. Graphite morphology has a significant effect on the erosion resistance of these irons in quartz-water and iron oxide-oil slurry. However, the matrix microstructure determines the erosion resistance of these irons in quartz-oil slurry. The parameter H/E (which is the ratio of the Brinell hardness number to Young's modulus of the material) has been found to be a good indicator of erosive wear in quartz-oil slurry.     

Wear behavior of alloyed hypereutectic gray cast iron

Alloyed gray cast iron of varying compositions was studied for their wear behavior. In general, the alloyed gray irons studied have higher graphite volume fraction (∼20%) with Type-A graphite flake morphology. Base cast iron showed two to three times higher wear rates than the alloyed gray irons. Tensile strength and wear rates show decreasing trend with increase in graphite and carbide volume fraction. Wear track analysis shows three body abrasive wear mode resulting in debris generation and smudging along the wear tracks. The graphite gets released during sliding to form films along the wear tracks and then forms irregular debris.     

Influence of the processing route on microstructure and mechanical properties of the polycrystalline NiAl

The influence of grain refinement on the mechanical properties of differently processed NiAl was presented. Five NiAl near‐stoichiometric alloys were investigated, three conventionally cast and two sintered from powders (fine‐grained powder made by mechanical alloying and nanopowder made by gas condensation). The mechanically alloyed and cast materials were hot extruded at different conditions to obtain diverse grain sizes. The nanomaterial was synthesized in inert gas condensation and then compacted at 1.4 GPa at 300 °C. It was shown that the ductility and strength can be directly controlled by appropriate texture and grain refinement.     

Effect of lubrication and green-compact shape on mechanical properties of mechanically alloyed Zn-22wt%Al powders during hot extrusion of spur gears

We investigated the extrusion behavior of mechanically alloyed Zn-22wt%Al powders with different lubricants and green-compact shapes. The mechanical alloying of powder particles was performed by planetary ball milling for 4 h, 8 h, 16 h, 32 h, and 64 h. The mechanical properties of these powders, as compacted and sintered cylindrical preforms, were estimated by uniaxial compression tests. The alloyed powder with an average particle size of 10 μm obtained after milling for 32 h had the highest compressive strength (288 MPa). Extrusions of miniature spur gears with pitch circles of 1.8 mm using the alloyed powder were carried out at different extrusion temperatures. An extrusion temperature of 310°C resulted in the highest Vickers hardness without surface defects when alloyed powder milled for 32 h was used. To investigate the effect of green-compact shape and lubricant on the dimensional accuracy and cracking regions during the first stage of hot extrusion, extrusion experiments with conical- or cylinder-type green compact shapes and BN spray or a graphite lubricant were performed at an extrusion temperature of 310°C. The results showed that the extrusion of spur gears by using the conical-shaped billet and graphite lubricant resulted in a low extrusion load, good surface roughness, a short cracking region during the first stage, and high dimensional accuracy.     

微量合金元素对D型石墨铸铁的影响

通过对D型石墨铸铁认识过程和形成条件的分析,阐述了微量合金元素对D型石墨铸铁的组织和性能的影响,对于提高铸铁的性能具有一定的指导价值.