耐热球墨可锻铸铁

耐热球墨可锻铸铁是一种新型的耐热铸铁，具体工艺是在中硅耐热球铁铁水中加入适量合金元素及变质剂，使之在铸态下得到白口组织，再经过石墨化退火而得到球团状石墨。该铸铁胶中硅耐热球铁有更为良好的常温力学性能及高温抗氧化性。尤其重要是的，因其凝固与结晶方式发生了质的改变，铸铁的缩松倾向得以明显改善。     

球墨可锻铸铁与可锻铸铁的冲击韧性对比

研究了硅量和温度对球墨可锻铸铁冲击韧性的影响。得出了球墨可锻铸铁的室温和低温冲击韧性高于含硅较低的可锻铸铁的结论。     

可锻铸铁热处理工艺的分析与研究

本文采用铁素体基体可锻铸铁材料,分别利用正火和等温淬火工艺进行处理,获得珠光体基体和贝氏体基体可锻铸铁,采用不同工艺处理的样品制备金相试样,并对典型组织进行照相,然后对两种热处理得到的组织进行分析和对比,获得性能和应用的区别。     

可锻铸铁多段热处理工艺研究

基于可锻铸铁的特点，成功开发了可锻铸铁多段加热热处理工艺。该工艺可使可锻铸铁铸件石墨化退火时间节约50%左右，获得了石墨核心多晶粒细小均匀分布，碳化物消除彻底的显微组织；产品综合力学性能超过了现行国际标准的性能指标，在现行国际及ISO5922－81《可锻铸铁》标准的基础上可增加KTH400－12和KTZ750－02两个牌号；经该工艺处理的线路工具、铁路管件、汽车发动机活塞等产品性能良好、质量可靠。     

KTZ700-2珠光体可锻铸铁凸轮轴的开发应用

研究了合金化元素铜和热处理工艺对珠光体可锻铸铁力学性能的影响,确定了ＫＴＺ７００ ２ 含铜珠光体可锻铸铁凸轮轴的热处理工艺。     

中国古代可锻铸铁的研究：—河南省渑池县南北朝铁镢的实验分析

铁镢、属于可锻铸铁，它是南北朝进期掘土的重要农具，我们用现代的测试仪器进行了铁镢的化学成分、组织和机械性能之间的研究较详细地分析其制造工艺，探讨其规律性，为发掘传统技术，将起到古为今用的作用。     

可锻铸铁高频感应热处理及金相组织分析

介绍了某轿车变速器零件A型齿轮的材料及热处理工艺，通过对可锻铸铁高频感应热处理前后的显微组织分析，认为用于高频感应热处理的零件材料应是珠光体型可锻铸铁；或者在高频感应热处理前经调质处理即采用铸造→调质→机加工→高频感应淬火的工艺。     

等温淬火对奥贝球铁上贝氏体转变动力学的影响

本文研究了等温淬火过程中奥氏体化温度和等温淬火温度对奥贝球铁上贝氏体第一阶段转变速度的影响及其机制；观察与测定了不同等温转变时奥贝球铁的组织与性能。结果表明，升高奥氏体化温度和等温淬火温度，使上贝氏体第一阶段转变速度减慢，在该转变结束时，奥贝球铁组织与性能最稳定。     

偏心盘和摆杆摩擦副的选材和工艺

针对无级变速器偏心盘和摆杆高速摩擦副的工作特性,在选材和加工工艺上,首次将可锻铸铁和中碳钢应用到摩擦副中,零件耐磨性和经济性取得了理想效果。     

粗轧机球墨铸钢水平辊开裂原因分析

某材料为球墨铸钢的粗轧机水平辊在使用很短时间后即发生径向开裂,采用宏观检验、化学成分分析、硬度试验、金相检验等方法对水平辊的开裂原因进行了分析。结果表明:不良的组织状态是导致水平辊开裂的主要原因;水平辊生产过程中未进行高温扩散退火,导致水平辊组织偏析严重,呈枝晶状分布,枝晶间隙碳化物粗大,数量较多,而枝晶杆处部分碳化物呈断续网状分布;另外,铸造过程中钢液石墨化工艺控制不佳,导致石墨数量少,球化效果差。     

Elevated temperature thermal conductivities of some as-cast and austempered cast irons

The aim of this study was to provide insight on thermal conductivity of three cast iron groups, namely lamellar, compacted and spheroidal graphite irons at elevated temperatures up to 673?K (400°C) in as-cast and austempered states. Austempering treatments increased mechanical properties of all the studied materials while decreasing thermal conductivity across the line. The effects of austempering on conductivity were lower for grey and compacted graphite iron than for spheroidal graphite irons. The results indicate that heat treating can be a viable option in increasing cast iron performance in thermally stressed applications. One ferritic low-silicon spheroidal graphite iron surpassed lamellar graphite iron in conductivity at elevated temperatures, while high-silicon spheroidal graphite irons exhibited low conductivities.     

多次多向等温变形对球墨铸铁石墨形态的影响

研究了球墨铸铁在900±10℃下,经不同方向多次压缩变形后石墨的形态变化.结果表明:单向压缩后石墨球变成近似平行分布的石墨片,经多向压缩后石墨片分裂;沿不同方向多次变形,石墨球在不同方向应力作用下被剪为小的石墨颗粒,起到了细化石墨球的作用.     

On the fatigue damage micromechanisms in Si‐solution–strengthened spheroidal graphite cast iron

Graphite nodules in spheroidal graphite cast iron (SGI) play a vital role in fatigue crack initiation and propagation. Graphite nodules growth morphology can go through transitions to form degenerated graphite elements other than spheroidal graphite nodules in SGI microstructure. These graphite particles significantly influence damage micromechanisms in SGI and could act differently than spheroidal graphite nodules. Most of the damage mechanism studies on SGI focused on the role of spheroidal graphite nodules on the stable crack propagation region. The role of degenerated graphite elements on SGI damage mechanisms has not been frequently studied. In this work, fatigue crack initiation and propagation tests were conducted on EN‐GJS‐500‐14 and observed under scanning electron microscope to understand the damage mechanisms for different graphite shapes. Crack initiation tests showed a dominant influence of degenerated graphite elements where early cracks initiated in the microstructure. Most of the spheroidal graphite nodules were unaffected at the early crack initiation stage, but few of them showed decohesion from the ferrite matrix and internal cracking. In the crack propagation region, graphite/ferrite matrix decohesion was the frequent damage mechanism observed with noticeable crack branching around graphite nodules and the crack passing through degenerated graphite elements. Finally, graphite nodules after decohesion acted like voids which grew and coalesced to form microcracks eventually causing rapid fracture of the remaining section.     

The Effect of Graphite Aspect Ratio on the Mechanical and Microstructural Properties of Cast Iron

Tensile test specimens of flake graphite (FG), compacted/vermicular (VG) and spheroidal graphite (SG) structures at five different cooling rates (RC) have been produced by deliberate techniques. The tensile strength (R_m), elongation percentage (A) and aspect ratio (AR) of the three graphite structures have been studied. The relationship between the aspect ratio range and mechanical properties of grey cast iron, compact graphite as well as spheroidal graphite were investigated. A comparative curve for the three graphite structures has been traced so as to correlate the aspect ratio values and the mechanical properties for each one.     

高强度轮毂的化学成分和熔炼处理工艺的研究

分析了轮毂的工作条件和基本性能要求,从保证其有良好强度和塑性韧性方面,采用强韧性较好的铸态铁素体球墨铸铁制造。对轮毂的化学成分进行设计,确定了其化学成分范围。选用低稀土镁合金的球化剂Re3Mg8,并采用冲入法进行球化处理,同时采用多次孕育处理及增加终硅量,强化孕育效果,使球墨铸铁的强度和塑性韧性得到提高。     

High Temperature Corrosion of Fe-C-S Cast Irons in Oxidizing and Sulfidizing Atmospheres

The corrosion behavior of spheroidal graphite and flake graphite cast irons was studied in oxidizing and sulfidizing atmospheres between 600 and 800℃ for 50 h. The corrosion rate in the sulfidizing atmosphere was faster than that in air above 700℃, due to the formation of the Fe0.975S sulfide. The corrosion rate of the spheroidal graphite cast iron was similar to that of the flake graphite cast iron.     

机械球磨制备碳微球及其吸附性能研究

分别以球墨铸铁和石墨为原料,采用机械球磨法成功制备了碳微球.采用XRD、SEM等测试手段对产物进行了形貌分析和结构表征,结果表明,所制备的碳微球产量高,并且以石墨为原料所得产物的颗粒大小均匀、分散性好.对碳微球进行了低温N_2吸附分析,结果表明,产物主要为介孔结构含有少量微孔,且具有较大的比表面积.