高铬合金铸铁化学成分的优化分析

通过分析对合金铸铁化学成分的添加及量的控制,改善高铬铸铁共晶碳化物的数量、形态和分布;通过稀土、钒、钛的微量加入及复合变质处理使高铬铸铁组织细化,并进一步改善碳化物形态,获得硬度、耐磨性和韧性的良好配合。     

高铬铸铁耐磨材料在泥沙磨损条件下耐磨性影响因素分析

分析了碳化物形态与分布、基体组织和稀土变质处理对高铬铸铁耐磨材料在泥沙磨损条件下的耐磨性影响。结果表明：碳化物的形态和分布对高铬铸铁的耐磨性有直接影响,块状或短杆状且分布均匀的碳化物对提高材料的耐磨性有利,网状或长针状碳化物对耐磨性不利;在泥沙磨损试验条件下,提高高铬铸铁中基体组织的显微硬度和基体组织与碳化物的结合强度有利于提高高铬铸铁材料的耐磨性;稀土元素的加入,使高铬铸铁的晶粒细化,碳化物颗粒变得细小,分布更为均匀,有利于提高高铬铸铁在泥沙磨损条件下的耐磨性。     

高铬铸铁热处理及其性能的研究

研究了高铬铸铁化学成分的控制范围、熔炼工艺、浇注工艺以及热处理工艺对其硬度；耐磨性和冲击性能的影响，并分析了该成分高铬铸铁经过不同热处理后的组织。结果表明，采用文中所述生产工艺和1040℃±10℃×6h特殊淬火液淬火＋275℃×6h或440℃×6h回火的热处理工艺，高铬铸铁硬度达60HRC以上，冲击韧性达10J／cm^2，其耐磨性是高铬铸铁Cr15的1．32倍、是高锰钢Mn13的1．95倍。     

低钨白口铸铁共晶碳化物团球化研究

研究了Ce、K、Na复合变质处理对钨白口铸铁组织和性能的影响。在常规热处理条件下,变质处理后的共晶碳化物变成了团球状。共晶碳化物形态的改善使得钨合金白口铸铁的力学性能,尤其是冲击韧性大幅度提高,其磨损性能也显著提高。     

变质处理对硼白口耐磨铸铁组织与性能的影响

本文考察了稀土,稀土—铝、■—氮变质处理对硼白口耐磨铸铁机械性能,碳化物形态,分布与热处理的影响。研究结果表明,复合变质处理可将连续网状碳化物转变为断续网状碳化物,从而提高抗弯强度和冲击韧性。其中,稀土—铝复合变质处理可降低退火温度,缩短保温时间和提高空淬能力。稀土适宜加入量为1.0～2.0%,铝适宜加入量为0.1～0.3%。     

稀土变质及热处理对高碳铬铸钢力学性能影响

研究了稀土变质与热处理对高碳铬铸钢力学性能的影响.采用金相显微镜、扫描电子显微镜观察了试样碳化物的形貌、冲击断口及磨面特征,用公式s=20.3 z/P2计算了碳化物的形状因子;采用冲击试验机、万能试验机等测试了试样的冲击韧性、抗弯强度、挠度;用动载磨损试验机对试样进行了磨损试验.结果表明:高碳铬铸钢经0.22％稀土变质后再经960℃×3 h正火,其冲击韧性提高180％,,抗磨性提高20％,强度提高76％,塑性也有所提高.其主要原因在于稀土变质及热处理使高碳铬铸钢组织中连续网状的共晶碳化物转变为孤立的块状、碳化物的形状因子增大以及粒状碳化物的析出所致.     

M2铸造高速钢的变质处理

用Re Al N复合变质剂对M 2铸造高速钢进行变质处理 ,消除了钢中网状共晶碳化物 ,细化了基体组织 ,减轻了W、Mo元素偏析 ,在不降低M 2高速钢硬度的情况下 ,韧性大幅度提高 ,经 1180～ 12 0 0℃淬火 ,5 6 0℃三次回火后 ,硬度保持在HRC6 5～ 6 6 ,冲击韧性由 8.5J提高到 17.0J。变质处理M 2铸造高速钢具有优异的抗热疲劳性能和抗高温磨损性能     

硼白口铸铁的研究

本文研究硼、铜、钼对白口铸铁（合碳３％左右）的硬度、冲击韧性及抗冲刷磨损性能的影响；不同热处理规范对组织、冲击韧性和抗冲刷磨损性能的影响；比较硼白铸铁和高铬自口铁的抗冲刷磨损性能．     

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:舍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...     

高铬离心复合铸铁轧辊辊身工作层剥落分析

高铬离心复合铸铁轧辊辊身工作层在热处理后发生大面积剥落,采用金相检验和化学分析等测试手段对 辊剥落进行了分析,结果表明,化学成分的不均匀分布,造成轧辊辊身工作层组织不连续、碳化物形态各异使螺身工作层硬度不均匀,产生大面积剥落,最终导致轧辊报废。     

Effect of multicomponent modifier on microstructure and mechanical properties of high Ni–Cr–Mo cast iron

Abstract

The microstructure and mechanical properties of high Ni–Cr–Mo indefinite chilled cast iron with the addition of a newly developed multicomponent modifier consisting of mixed rare earths, Si–Ca alloy and Bi–Sb alloy have been investigated through optical microscopy, X-ray diffraction and scanning electron microscopy, along with hardness, impact toughness and wear resistance measurements. After the addition of the modifier, the grain sizes of the primary austenite and eutectic carbides are found to be greatly refined, and the typically highly continuous net-like carbides become less interconnected but rather appear more blocky shaped. Such microstructure changes lead to mechanical property improvement in the cast specimen, with its hardness increased from 43 to 50 HRC, impact toughness from 6·3 to 7·8 J cm^?2 and ?20% increase in abrasive wear resistance.     

热处理回火温度对Cr26高铬铸铁组织与性能的影响

目前,有关淬火后回火温度对Cr26高铬铸铁组织及性能的研究报道不多。为此,采用XRD、OM、SEM、TEM和电子拉力试验机和洛式硬度计,研究了回火温度对Cr26高铬铸铁调质处理前后的显微组织和力学性能的影响。结果表明:调质处理前Cr26高铬铸铁中碳化物类型有M_7C_3、M_(23)C_6和M_3C_2;调质处理后Cr26高铬铸铁的显微组织得到明显改善,基体上弥散分布着细小的碳化物;抗拉强度和硬度值随回火温度的增加而降低,延伸率有所提高;回火温度为560℃左右时,抗拉强度、延伸率和硬度值分别为1 294 MPa、8.02%和38.6 HRC,有良好的力学性能。     

烧结Cr15高铬铸铁组织与性能的研究

为研发耐磨性能优良、成本相对低廉的高铬铸铁,本文分别以亚共晶、过共晶的水雾化Cr15高铬铸铁粉末为原料,采用超固相线液相烧结工艺制备了烧结高铬铸铁(SHCCI),并对其显微组织、力学性能和冲击磨粒磨损工况下的耐磨性能进行对比研究。结果表明,烧结高铬铸铁主要由M7C3碳化物、马氏体和奥氏体组成;在亚共晶烧结高铬铸铁中,通过电解腐蚀萃取的M7C3碳化物三维形貌呈珊瑚状,沿晶界均匀分布,材料抗冲击耐磨性能优良;在过共晶烧结高铬铸铁中,优先形成的初生碳化物可能成为共晶碳化物的生长基底,形成核-壳结构的M7C3碳化物,沿晶界相互连接呈网状,严重割裂基体。亚共晶、过共晶烧结高铬铸铁的力学性能分别为:硬度HRC63.9、HRC64.3,冲击韧性7.92、3.04 J/cm^2,抗弯强度2112.65、1624.87 MPa。     

Influence of carbon diffusion on microstructure and wear behaviour of duplex stainless steel surface layers on lamellar grey cast iron

Surface welding with duplex stainless steel was performed to enhance the wear and corrosion properties of grey cast iron, which is used as material for applications as pump components in maritime and chemical environments. The method used for surface welding and the corresponding process parameters determine the chemical composition and microstructure, which both determine the corrosion and wear properties of the surface layer. High heat input leads to high chemical dilution and thus, reduced corrosion resistance. Slow cooling rates, which are recommended for welding of grey cast iron components, facilitate the formation of carbides in the fusion zone of the chromium‐rich duplex stainless steel surface layer. On the one hand, carbides lead to increased hardness and thus, improved wear resistance of the surface layers. On the other hand, carbides and high chemical dilution rates reduce the corrosion resistance and therefore should be avoided. Under high cooling rates, the risk of cracking in the heat affected zone of the grey cast iron increases due to martensitic phase transformations. The paper describes the correlation of process parameters, microstructure and chemical composition with a focus on carbon diffusion and carbide formation, ever considering the effect on the wear behaviour in an oscillation tribometer and under erosion‐corrosion conditions.     

TiCp/Cr15高铬铸铁复合材料的制备与性能

以TiC_p粉末和水雾化Cr15高铬铸铁粉末为原料,采用粉末冶金液相烧结技术制备TiC_p增强高铬铸铁复合材料。研究了TiC_p含量对高铬铸铁的物相组成、显微组织和力学性能的影响。研究结果表明,全致密的TiC_p增强高铬铸铁基体复合材料的构成相为TiC、M₇C₃型碳化物、马氏体和少量奥氏体;随着TiC_p添加量增大,金属基体逐步呈孤岛状,并在其中析出越来越多的M₇C₃型碳化物,同时TiC_p逐步呈连续网状分布;同时,其硬度稳步提升,而抗弯强度和冲击韧性降低。当TiC_p添加量为20wt%时烧结态复合材料具有最佳综合力学性能。此时硬度为HRC 66.8 ,冲击韧性为6.86 J/cm2,抗弯强度为1 343.10 MPa。当TiC_p添加量为25wt%时硬度达到最大值HRC 67.20 。      

Effects of Heat Treatment on Hardness and Dry Wear Properties of a Semi-Solid Processed Fe-27 wt pct Cr-2.9 wt pct C Cast Iron

EfFects of heat treatments on hardness and dry wear properties of a semi-solid processed Fe-26.96 wt pct Cr- 2.91 wt pct C cast iron were studied. Heat treatments included tempering at 500℃, destabilisation at 1075℃ and destabilisation at 1075℃ plus tempering at 500℃, all followed by air cooling. Electron microscopy revealed that, in the as-cast condition, the primary proeutectic austenite was round in shape while the eutectic M7C3 carbide was found as radiating clusters mixed with directional clusters. Tempering did not change the microstructure significantly when observed by scanning or transmission electron microscopy. Destabilisation followed by air cooling led to a precipitation of secondary M23C6 carbide and a transformation of the primary austenite to martensite. Precipitation behaviour is comparable to that observed in the conventionally cast iron. Tempering after destabilisation resulted in a higher amount of secondary carbide precipitation within the tempered martensite in the eutectic structure. Vickers macrohardness and microhardness in the proeutectic zones were measured. Dry wear properties were tested by using a pin-on-disc method. The maximum hardness and the lowest dry wear rate were obtained from the destabilisation-plus-tempering heat treatment due to the precipitation of secondary carbides within the martensite matrix and a possible reduction in the retained austenite.     

Effects of deep cryogenic treatment on property of 3Cr13Mo1V1.5 high chromium cast iron

Effects of deep cryogenic treatment on the microstructure, hardening behavior and abrasion resistance of 3Cr13Mo1V1.5 high chromium cast iron subjected to sub-critical treatment were investigated in this paper. The results show that deep cryogenic treatment after sub-critical treatment, the hardness and abrasion resistance of high chromium cast iron can be boosted obviously due to abundant retained austenite transforming into martensite and secondary carbides precipitation. In the course of sub-critical treatment with cryogenic treatment, the amount of precipitated secondary carbides was more than that in air cooling, and the secondary hardening peak advanced at a lower temperature. When abrasion resistance reach the maximal, there was about 20% retained austenite in microstructures. Cryogenic treatment can further reduce the austenite content but can not make retained austenite transform to martensite completely.     

Effects of surface alloying on microstructure and wear behavior of ductile iron

In this research, the effect of austenitic stainless steel cladding on improving the wear behavior of ductile iron was studied. Samples made of ductile iron were coated with steel electrodes (E309L) by manual shielded metal arc welding. The effect of coated layer thickness on microstructure, hardness, and wear resistance of the surface were investigated. Wear resistance of the samples was measured using the pin-on-plate technique. Optical microscopy and scanning electron microscopy were used to investigate microstructure and wear mechanisms. The phases in the interface of both the coating and the substrate were studied by X-ray diffraction. The results showed that a film of white chromium-enriched iron formed at the interface between the substrate and coating which contained iron–chromium complex carbides. It was, therefore, concluded that enhanced properties would be obtained if the coating thickness and the carbides deposited on the surface were reduced. In samples with a thin coating, surface hardness rose to above 1150 HV (five times higher than that of the substrate) and wear resistance increased significantly.     

硼白口铸铁的研究进展

白口铸铁的合金化主宰了其发展进程.介绍了硼合金化白口铸铁的研究状况,主要阐述了硼对以碳化物为耐磨相和以硼化物为耐磨相的白口铸铁中组织和性能的影响.硼不改变以碳化物为耐磨相的白口铸铁中碳化物的形态,但能提高碳化物硬度和基体的淬透性,对韧性没有明显改善.以硼化物为耐磨相的白口铸铁组织中含有硬的硼化物耐磨相和强韧的马氏体基体,具有良好的硬度和韧性组合,是一类非常具有前途的新型白口铸铁.     

16Cr-2.5Mn高铬白口铁的亚临界热处理研究

研究了亚临界热处理对16Cr-2．5Mn高铬白口铁组织转变和性能的影响，并利用TEM、SEM、XRD和M200磨损试验机分析了其硬化机制和对耐磨性的影响．研究表明：过饱和奥氏体中固溶的Cr和C在亚临界热处理时会以（Cr，Fe）23C6形式析出，残余奥氏体发生了马氏体相变，使合金产生二次硬化；亚临界热处理中，保温时间过长，将导致（Cr，Fe）23C6向M3C原位转变发生，基体组织发生珠光体转变，导致硬度和耐磨性能不同程度降低；残余奥氏体含量为10％左右时，合金获得最高硬度和最佳耐磨性能．