Effect of Microstructure on Impact Wear Resistance Impact Fatigue Resistance and of Medium Cr-Si Cast Iron

A great amount of iron grinding balls in tube mills have been consumed. Under this impact abrasive wear working condition, the failure of wear resistant alloying white irons grinding balls is mainly caused by fatigue spalling. The impact wear resistance of martensitic high chromium cast iron （Cr of 15%） is not high sometimes, but its cost is not low. Thus, medium Cr-Si wear resistant cast iron is recommended. The influence of the iron on impact fatigue resistance and impact wear resistance is pronounced. Ball-on-ball impact fatigue test and high stress impact wear test of the grinding balls have been carried out. The results show that the impact fatigue resistance （IFR） and impact wear resistance （IWR） of medium Cr-Si cast iron are superior to those of martensitic high chromium cast iron （Cr of 15%）. The main reasons are that （1） the stress in medium Cr-Si cast iron is released in the as-cast state; （2） the matrix is fine pearlite with better toughness and plasticity; （3） the pearlite is more stable compared with a retained austenite under repeated impact load and less phase transformation can take place; （4） high silicon content im- proves the morphology of eutectic carbide; （5） there is no seeondary carbide which results in less crack sources. All these factors are beneficial to improvement of impact fatigue spalling resistance. The eutectic carbide M7C3 is the main constituent to resist wear.     

Microstructure, Impact Fatigue Resistance and Impact Wear Resistance of Wear Resistant Low Cr-Si Cast Iron

Wear parts are greatly consumed in metallurgi-cal industry,fire power stations and cement works.The consumption of grinding balls and lining platesmay be the greatestunder such impactabrasive wearconditions.In China,annual consumption of ballsand plates is close to 1× 10 6 t.Therefore,develop-ing a new material for impact wear conditions is veryimportant.　　 The martensitic high chromium cast iron(WCr= 15 % ) is widely studied and used as wear resis-tance material[1— 8] ,especially for ma…     

Effect of RE Modification and Heat Treatment on Impact Fatigue Property of a Wear Resistant White Cast Iron

Withhigherhardnessandbetterwearresistance ,whitecastironscanbeusedaswearresistantpartsinmanyfields .Inpractice ,thewearresistantpartsareoftenrequiredtobesubjectedtogrindingofabrasivesandrepeatedimpactaction .Therefore ,fatiguecracksareliabletobegeneratedo…     

Study on the Thermal Fatigue Behavior of Hot Deformed Wear Resistance Cast Iron and Effect of Carbide

The thermal fatigue behavior of wear resistance cast iron with different quantity of deformation has been investigated. The results show that eutectic carbide is the main location and passage for initiation and extension of thermal fatigue cracks, approving that the more serious, the carbide breaks. The higher thermal fatigue resistance of wear resistance cast iron will be and thermal fatigue fracture belongs mainly to brittleness.     

铈对中铝耐热铸铁组织和力学性能的影响

中铝耐热铸铁因其脆性大使用受到限制。研究了Ce对中铝耐热铸铁的组织及力学性能的影响。结果表明:Ce可使中铝耐热铸铁的石墨球化,组织细化,力学性能得到明显改善。     

Effect of Hot Deformation on Formation and Growth of Thermal Fatigue Crack in Chromium Wear Resistant Cast Iron

Chromium wear resistant cast iron is widelyusedin engineering, mining and power industry forits high strength,hardness and wear resistance .Inproduction process , some wear-resistant parts ser-ving in alternative stress due to rapid heating andcooling rate ofteninduces thermal fatigue andresultsinfailure .The badthermal fatigue property of chro-mium wear resistant cast iron is due to eutectic car-bides which distribute as continuous net in matrix.Recent researches showthat hot deformation can …     

硼对耐磨球墨铸铁组织和力学性能的影响

研究了不同硼含量对含碳3．4％－3．8％、含硅2．0％－3．0％,含锰2．0％－＝3．0％的球墨铸铁铸主热处理态组织和力学性能的影响。结果表明：随着硼含量的增加,铸态组织中的碳化物数量增加,硬度提高,冲击韧性下降,当硼含量大于0．010％时,铸态组织中出现了明显的网状或断网状碳化物,冲击韧性下降幅度较大,经淬火、回火后、碳化物发生不同程度的溶解。当硼含量为0．003％－0．0105时,热处理后碳化物基本消失,硬度保持在HRC50左右,冲击韧性达到或超过9J／cm^2;当硼含量超过0．010％时,热处理后仍存在断网状或条块状碳化物,硬度稍有增加,冲击初性明显下降。     

Wear Behavior and Mechanism of Spheroidal Graphite Cast Iron

Wear behavior and mechanism of spheroidal graphite cast iron were studied on a pin-on-disk elevated temperature wear tester. The phase and morphology of worn surfaces were examined by X-ray diffraction and scanning electron microscopy. Results show that with an increase of load, wear rate of spheroidal graphite cast iron gradually increases under low loads, rapidly increases or potentially increases under high loads; wear rate increases with increasing ambient temperature. At 25–200 °C, adhesive wear prevails; oxidative wear and adhesive wear coexist at 100 °C. As load surpasses 150 N at 100 °C, extrusive wear appears. The elevated-temperature wear of spheroidal graphite cast iron is a physical and chemical process including the following reactions: xFe + y/2O₂?Fe_xO_y, 2C + O₂?2CO and Fe_xOy + yCO?xFe+yCO₂. Hence, at 400 °C, the amount of graphite and tribo-oxides are substantially reduced because of reductive function of graphite. It can be suggested that wear-reduced effect of graphite and tribo-oxides is impaired.     

Effect of RE Complex Inoculation on the Fatigue Wear Behaviours of High Chromium Cast Iron

ＥｆｆｅｃｔｏｆＲＥＣｏｍｐｌｅｘＩｎｏｃｕｌａｔｉｏｎｏｎｔｈｅＦａｔｉｇｕｅＷｅａｒＢｅｈａｖｉｏｕｒｓｏｆＨｉｇｈＣｈｒｏｍｉｕｍＣａｓｔＩｒｏｎＷａｎｇＪｉｕｂｉｎ（ＩｎｓｔｉｔｕｔｅｏｆＩｒｏｎ＆ＳｔｅｅｌＲｅｓｅａｒｃｈ，ＡｎｓｈａｎＩｒ...     

残余奥氏体对中锰白口铸铁力学性能和抗磨性的影响

研究了残余奥体对中锰白口铸铁力学性能和抗磨性的影响,结果表明,冰冷处理是改变显微组织中残余奥氏体量和马氏体量的可靠工艺。随显微组织中残余奥氏体量的减少,材料的硬度提高、冲击韧性降低。残余奥氏体含量为３０％时,模拟试验的抗磨性最好,用于制造中小型球磨机衬板的中锰白口铸铁,合适的残余奥氏体含量为３０％－３５％,此时可以达到硬度、韧性和抗磨性的最佳配合。     

合金球墨铸铁基体组织对含镍球墨铸铁热疲劳性能的影响

将同炉熔炼并同时浇铸的 ,镍约 0 .7%的合金球墨铸铁楔形试块粗加工后热处理成 6种基体组织 ,再精加工成 2 0 m m× 2 0 m m圆柱试样。对试样进行了 (6 0 0± 10 )℃ (盐浴 )～ (70± 30 )℃(油 )和 (6 5 0± 10 )℃ (盐浴 )～ (2 5± 5 )℃ (水 )两种冷热循环试验 ,得到了一致的结果。发现 ,不同基体的试样其抗热疲劳性能由高到低依次为 :下贝氏体基体→ 5 6 0℃回火调质基体→ 5 80℃回火调质基体→ 6 0 0℃回火调质基体→正火片状珠光体基体→奥 -贝基体。作者结合不同基体组织的硬度和强度以及 Ac1 点以下温度范围内上述各种基体组织的热力学稳定性等因素对热疲劳性能的影响 ,阐明了导致上述试验结果的原因。     

Effect of Rare Earth Elements on Thermal Fatigue of High Ni－Cr Alloy Cast Iron

ＥｆｆｅｃｔｏｆＲａｒｅＥａｒｔｈＥｌｅｍｅｎｔｓｏｎＴｈｅｒｍａｌＦａｔｉｇｕｅｏｆＨｉｇｈＮｉ－ＣｒＡｌｌｏｙＣａｓｔＩｒｏｎＹａｎｇＱｉｎｇｘｉａｎｇ（杨庆祥）；ＷａｎｇＡｉｒｏｎｇ（王爱荣）；ＲｅｎＸｕｅｊｕｎ（任学军）；ＷｕＨａｏｑｕａｎ（...     

合金元素对奥氏体-贝氏体型球墨铸铁组织和性能的影响

根据不同的合金元素对球墨铸铁基体组织的影响，将锰、钼、镍和铜的含量合理搭配，以岩棉为冷却介质，在连续冷却过程中获得了性能较好的奥氏体-贝氏体型球墨铸铁，HRC可达33～48，αk可达26～48J／cm^2。     

稀土对Ni-Cr-Cu合金铸铁组织及耐碱腐蚀性能的影响

设计了不同含量的稀土镍-铬-铜合金铸铁,采用光学显微镜观察组织,用失重法测定合金铸铁在动态、高温、高浓度碱液中的腐蚀速率。结果表明,添加稀土可以改善合金铸铁中石墨的形态及分布,使之由长条形逐渐球化;并且随着稀土含量的增加,石墨数量增加,合金铸铁的耐蚀性增强。但稀土过量会使得合金铸铁的耐蚀性减弱。     

稀土对Fe－C－Al－Si铸铁组织和性能的影响

本文研究了稀土对Ｆｅ－Ｃ－Ａｌ－Ｓｉ铸铁的石墨形态，基体组织，力学性能及激冷倾向的影响。随１~＃稀土量增加，石墨由片状向蠕虫状转变较快，但由蠕虫状向球状转变很慢，故具有较大的蠕化范围。铸铁的强度在０．３～１．２％１~＃稀土范围内随稀土的增加而增加，但在１．２～２．０％范围内稍有下降。稀土具有较强的促进激冷倾向的能力，而铝具有抑制或消除激冷倾向的作用。孕育能显著降低激冷倾向，且其效果比普通铸铁更明显。并对有关机理进行了讨论。     

振动时效激振力对白口铸铁工件疲劳寿命的影响

从理论上分析了振动时效激振力对白口铸铁工件疲劳寿命的影响,确定了白口铸铁疲劳破坏工件振动时效激振力的选择依据。此依据在大型铬钼冷硬球墨复合铸铁轧辊的振动时效中获得了成功运用。     

Effect of Manganese on As-Cast Microstructure and Hardening Behavior of High Chromium White Cast Iron

Highchromiumwhitecastironhasbeenusedaswear resistantmaterialsintheminingandmaterialin dustryduetotheirexcellentabrasionresistanceforhardeutecticcarbidesinthemicrostructure[1- 3] .Highchromiumwhitecastironiscommonlyusedafterheattreatment .Thealloyelementsw…     

高温下奥—贝蠕铁的组织与性能

奥—贝蠕铁是继奥—贝球铁之后发展起来的新型工程材料之一，也是世界上正在开发的材料。本文系统地提供了奥—贝蠕铁的制取工艺，奥—贝蠕铁的组织特征及其在常温及随温度提高力学性能变化的规律。研究表明，以稀土硅铁为蠕化剂，所制取的蠕化率大于９０％、基体以铁素体为主的蠕墨铸铁，经等温淬火后，可稳定地获得奥氏体—贝氏体基体（以下简称奥—贝蠕铁），它有较好的综合性能，在常温下σｂ＝８２０～９３７．５ＭＰａ，δ＝０．４０％～０．７８％；在６００℃时，σｂ＝１５８～１８７ＭＰａ，δ＝４．００％～７．８４％，仍超过ＨＴ１５０的常温性能。当低于３００℃时组织和性能稳定性较好，是适宜的工作温度范围     

高铬镍无限冷硬铸铁轧辊材料的磨损性试验

利用自行开发研制的高温滑动磨损与热接触疲劳材料试验机,并运用表面覆膜技术、金相分析和扫描电镜,研究了用于精轧机的高铬镍无限冷硬铸铁轧辊材料在热轧状态下的耐磨特性,分析了这种轧辊材料的表面形貌、表层组织的变化情况。结果表明,当轧制公里数达到88km时,高铬镍无限冷硬铸铁轧辊表面产生了碳化物的浮凸和剥落。     

灰铸铁缸体断裂失效分析

通过对灰铸铁缸体断口处化学成分、金相组织、断裂腐蚀产物等因素进行分析,得出机体材料组织状态、螺纹加工状态不良是造成机件发生早期疲劳断裂的因素之一。而且由于结构设计原因,安装过程可能在断面局部形成较大的拉应力,也是造成机件发生早期疲劳断裂的重要因素。