M－B－A复相基体及M基体中铬铸铁湿态磨料磨损特性

着重对比探讨马氏体－贝氏体－奥氏体（Ｍ－Ｂ－Ａ）复相中铬铸铁和马氏体中铬铸铁的湿态磨料磨损特性。研究表明，冲击载荷、高应力湿态磨料磨损条件下（冲击功１．４７Ｊ，２．４５Ｊ），疲劳剥落是主要磨损机制，复相基体中铬铸铁的磨损速度低于马氏体中铬铸铁。而低应力湿态磨料磨损中显微切削是主要磨损机制，马氏体中铬铸铁的磨损失重低于复相基体中铬铸铁。     

不同碳含量高硬度共晶高铬铸铁的微观组织与力学性能

通过控制不同元素含量制备出含有2.9%碳和3.1%碳(质量百分比)的两种共晶高铬铸铁，并讨论了碳元素对共晶高铬铸铁微观组织与力学性能的影响。研究结果表明，两种高铬铸铁微观组织和力学性能存在显著差异。Ni、Mo、Mn、Cu和稀土元素的复合合金化以及优化热处理工艺可以控制碳化物的分布和数量，从而进一步提高样品硬度。此外通过弯曲和冲击测试，证实了两种不同碳含量的共晶高铬铸铁合金都具有优秀的硬度(65HRC)、抗弯强度(≥1160 MPa)和冲击韧性(≥2.88 J)。3.1%的较高碳含量导致铸态样品具有更高硬度，但抗弯强度明显降低。     

锻造高铬铸铁的组织和性能

本文对高铬铸铁进行单向拔长热塑性变形试验,研究了锻造比(K_L)为1～4.14的高铬铸铁的组织、机械性能和抗磨料磨损性能。结果发现随着K_L增大,碳化物分布越来越均匀、孤立和细化;抗弯强度、冲击韧性及抗磨料磨损能力明显提高,而硬度变化不大。     

不同铬含量白口铸铁的抗小麦粉料磨粒磨损性能

利用模拟辊式制粉工况磨损试验机,对铬含量(质量分数,下同)分别为0,1.2%,4.0%的3种白口铸铁进行了小麦粉料磨损试验,研究了铬含量对白口铸铁磨损质量损失和磨损形貌的影响。结果表明:铬的添加能提高白口铸铁的抗小麦粉料磨损能力,铬含量为4.0%时,白口铸铁的磨损质量损失约为铬含量为0时的32%;随着铬含量的提高,白口铸铁被磨面的沟槽宽度与深度、棱脊峰谷值,以及金属元素含量均有所降低,但硬度显著增大,并且磨损表面的犁沟变浅变窄,犁沟两侧的犁皱变得不明显。     

铸态高铬铸铁柱状晶粒区耐磨性研究

在二体磨料磨损系统中,使用不同硬度的磨料研究了２８％Ｃｒ铸铁柱状晶粒区不同方向上的耐磨性。结果表明,碳化物位向对铸铁耐磨性的影响与磨料硬度有关。使用硬磨料时碳化物位向对铸铁耐磨性的影响很小,使用中等硬度的磨料时碳化物纤维垂直于磨损面排列会降低铸铁的耐磨性,当使用低硬度磨料,碳化物纤维垂直于磨损面排列时才显著提高铸铁的耐磨性。     

高钒高速钢的耐磨性研究

作者通过改变高速钢中含钒量和含碳量,得到不同微观组织和机械性能的磨料基体,并对其磨损性展开研究.结果表明:高速钢的耐磨性通常取决于其硬度和微观结构.硬度低于58HRC时,高速钢耐磨性主要受硬度影响;硬度高于58HRC时,其耐磨性主要取决于基体中VC的含量、形态及分布.当钒和碳含量分别在8.15％～10.20％和2.70％～3.15％之间时,可以得到大量的均匀分布球形组织或块状VC化合物,这种基体组织可以有效抵抗三氧化铝磨料的微切割,并且削弱裂纹的扩展和加深.正因为如此,高钒碳含量的高速钢表现出优良的耐磨性.     

冲击疲劳试验在高铬铸铁研究中的应用

用自制的CJPL—01型冲击疲劳试验机对含铬20％的高铬铸铁进行小能量多次冲击疲劳特性研究，并测定其摆锤式冲击韧度、硬度和疲劳型磨料磨损性能。对试验数据进行回归分析，结果表明冲击疲劳性能可以较准确地反映出高铬铸铁韧性、硬度与疲劳型磨料磨损性能之间的关系。分析了冲击疲劳断口和摆锤式冲击断口，认为冲击疲劳性能不仅可以舞准确地衡量高铬铸铁的韧性，而且能够较好地体现脆性材料抵抗裂纹萌生和扩展的能力。     

高铬铸铁磨料磨损耐磨性的研究

高铬铸铁在磨料磨损条件下工作具有较好的耐磨性和应用效果。为了进一步地发挥高铬铸铁的优点，特别是在复合结构特定条件下能够取得耐磨性的第一手资料，对高铭铸铁的低应力磨料磨损、冲击条件下的磨料磨损、宏观硬度和金相组织等作了系列的试验研究，现将结果介绍如下。一、试验内容在化学成分方面，采取分别改变铬、碳和硼的加入量来观察高铭铸铁的组织和耐磨性的变化。试样的化学成分加附表所示（附表见后）。热处理对高铝铸铁的组织和性能有重要影响，为此分别取铸态、950℃正火和1050℃正火三种状态，试样共有72种成分状态。在自制的…     

原位生成(Fe,Cr)_7C_3/Fe复合材料的磨料磨损性能

将纯铬丝放入开有相应圆孔的HT250灰铸铁中,在1 220℃保温30min进行原位反应,制备出了不同体积分数(Fe,Cr)7C3的铁基复合材料,并采用XRD、SEM、硬度仪及磨损试验机等对复合材料的物相组成、显微组织、显微硬度及其磨料磨损性能进行了研究。结果表明:复合材料的物相主要由碳化物(Fe,Cr)7C3、铁素体(α-Fe)及奥氏体(γ-Fe)组成;随碳化物体积分数的增加,复合材料的平均显微硬度逐渐增大,最高值为1 453HV0.1;而在磨料磨损条件下的磨损量先降后升,碳化物体积分数为62%时复合材料的耐磨性最好,且与BTM20Cr高铬铸铁的耐磨性相当。     

定向凝固高铬铸铁抗冲击磨损研究

选用共晶成分高铬铸铁制成了定向凝固试样，探讨了碳化物定向排列和碳化物间距对高铬铸铁抗冲击磨损的影响。结果表明，碳化物垂直于磨损面定向排列后合金耐磨性均有不同程度提高。碳化物间距对合金耐磨性的影响较复杂，使用石英砂和氧化铝磨料时合金耐磨性随碳化物纤维尺寸的变化曲线 有一峰值；使用水泥熟料时碳化物纤维尺寸的的变化对合金耐磨性影响不明显。     

B4C 含量对堆焊高铬合金耐磨性的影响

堆焊合金中合金元素 Cr 和 V 与堆焊层中的 C 形成 Cr7C3及 VC 等硬质相,在此基础上加入B 元素,形成相应的 TiB2,可进一步增加其硬度和耐磨性;因此,在高 Cr 合金中加入 B4C 制成粉芯,用埋弧焊堆焊的方法得到合金,测量宏观硬度并且观察了显微组织。结果显示,随着 B4C 含量增加,试样中硬质相比例增加,提高了试样的硬度,一定程度上增加了耐磨性（B4C 含量1.5%-3.5%为宜）;但 B4C 含量过高（B4C 含量达到3.0%左右）,晶界偏析加大,易导致堆焊层开裂。     

Effects of Chromium Addition on Microstructure and Abrasion Resistance of Fe–B Cast Alloy

This research work studies the effects of chromium on microstructure and abrasion resistance of Fe–B cast alloy. The results show that eutectic boride changes from continuous network to less continuous and matrix changes from pearlite to martensite with the increase in chromium content in the alloy. Meanwhile, an increase in chromium addition in the alloy leads to an increase in the chromium content in M₂B-type boride because chromium can enter boride by substituting for iron in Fe₂B. Under two-body wear, Fe–B cast alloy exhibits excellent wear resistance. When alloys are tested against soft abrasive, chromium can markedly improve the wear resistance of Fe–B cast alloy, whereas excessive chromium can reduce the wear resistance. The wear resistance of Fe–B cast alloy increases first and then decreases with the increase in chromium. But when tested against hard abrasive, since the hardness of SiC is much higher than that of M₂B boride, an increase in chromium content marginally increases the wear resistance. Weight losses of Fe–B cast alloy increase with the increase in the load and exhibit the linear relationship.     

耐磨铸钢在火电厂磨机衬板上的应用研究

为了满足火电厂磨机的安全运行，开发了一种高强度、高韧性低合金耐磨铸钢衬板。该高强度低合金耐磨铸钢以锰、硅为主要合金元素，加入不超过2．0％的铬。不含钼、镍等昂贵合金元素，并加入适量的钛、氮、稀上、钙、镁，改善铸钢的强度和耐磨性，合金总加入量控制在5％以内。热处理后，其基体组织以屿氏体为主，马氏体板条间含有大量纳米级奥氏体薄膜，使材料保持高强度和高硬度的前提下，还具有优良的韧性。着重介绍了耐磨铸钢衬板的微合金化技术、铸造技术和热处理技术，规模化制备了高强度低合金耐磨铸钢衬板，并在火电厂磨机上进行了工业应用。使用考核表明，低合金铸钢衬板在火电厂磨机上使用安全、呵靠，寿命比高锰钢衬板提高160％-210％，而生产成本相当，推广应用具有良好的经济效益和社会效益。     

The use of transmission electron microscopy to study the effects of abrasive wear on the matrix structure of a high chromium cast iron

The wear behaviour of an austenitic high chromium cast iron was investigated under conditions of high stress abrasion using a specimen-on-track test apparatus. The austenite matrix at the wear surfaces of test specimens work hardened during abrasion giving hardness values up to 950 HV but the depth of hardening was seen to be much smaller than that obtained under service conditions. The nature of the work hardening was studied by thin foil transmission electron microscopy. This work has provided evidence of strain-induced martensite formation which is believed to be responsible for the observed increases in hardness.     

高铬铸铁耐磨球热处理工艺研究

研究了一种添加微量合金元素Mo、V、Nb的高铬铸铁耐磨球的热处理工艺。采用在980℃淬火、400℃和600℃回火的热处理工艺。通过显微组织分析可知淬火后基体组织为淬火马氏体,400℃回火后基体组织为回火托氏体,600℃回火后基体组织为回火索氏体。经硬度分析和耐磨性分析可知：仅淬火处理时试样硬度为65HRC,磨损量也最小;400℃回火后硬度下降为62.8HRC,磨损量比淬火态增加18.2%;600℃回火后硬度下降为57.6HRC,磨损量比淬火态增加30.3%。结合磨球实际应用状态最佳热处理工艺应采用980℃淬火、400℃回火。     

Influence of abrasive hardness on the wear resistance of high chromium irons

The resistance to abrasive wear was determined for a series of alloyed white cast irons in a high stress abrasion test which utilizes a specimen in sliding contact with bonded abrasives. These were conducted on silicon carbide, alumina and two sizes of garnet abrasive.The results indicate that the hardness, or type, of abrasive used in the test significantly influenced the wear rate of white irons, i.e. the rate of wear increased with increasing hardness of the abrasive. Also, the results indicate that the type of abrasive used in the test was a significant factor in ranking white irons for resistance to high stress abrasion. When tested on silicon carbide or alumina abrasive, as-cast austenitic irons exhibited lower rates of wear than heat treated martensitic irons; when tested on garnet, an abrasive of lower hardness, those irons with martensitic matrix microstructures exhibited the same or less wear than irons with austenitic matrix microstructures. It was also evident that heat treated irons with martensitic matrix microstructures exhibited varying degrees of resistance to abrasive wear depending on cooling rates and alloy content.     

Effect of cryogenic treatment on the matrix structure and abrasion resistance of white cast iron subjected to destabilization treatment

Effect of deep cryogenic treatment on the matrix structure and abrasion resistance of high chromium cast iron subjected to destabilization heat treatment has been investigated in this paper. The results show that, during the cryogenic treatment, the secondary carbides precipitate in austenite, which promote the transformation of retained austenite to martensite. The cryogenic treated alloys produced superior hardness and wear resistance (β) to the alloys without cryogenic treatment. When the bulk hardness and wear resistance (β) reach the maximum, there is still about 13% retained austenite in alloys. Cryogenic treatment cannot make retained austenite transform to martensite completely.     

加硼高铬铸铁

从降低成本和提高耐磨性的角度出发 ,对高铬铸铁进行了加硼的试验研究。考察了加硼量和热处理工艺对高铬铸铁的硬度和冲击韧性的影响 ,并进行了销盘磨损试验。实验结果表明 :只要添加适量的硼和采取合适的热处理工艺 ,可以使高铬铸铁的碳化物细化 ,基体淬透性增加 ,并使高铬铸铁的硬度和韧性同时得到提高 ,从而增加了材料的耐磨性。     

A study of sand slurry erosion of W-alloy white cast irons

This paper reports the results of a study into the effects of the composition, hardness and electrochemical properties of W-group cast irons on sand slurry-erosion resistance and wear mechanisms. The results indicate that the sand slurry-erosion resistance of the irons can be raised by increasing the content of tungsten, especially when the iron is alloyed with chromium. The relation between macrohardness and sand slurry-erosion is intricate. In the low hardness range, the sand slurry-erosion resistance is linearly increased with hardness, but this relationship does not exist in the high hardness range. The sand slurry-erosion resistance of cast iron can be considerably increased by increasing its corrosion resistance. Sand slurry-erosion is an abrasive wear process accompanied by corrosion and cavitation, all of which aggravate each other.     

MPS（MBF）型中速磨煤机用高铬白口铸铁磨辊的研制

在分析ＭＰＳ（ＭＢＦ）型中速磨煤机用磨辊的工况条件和性能要求的基础上，结合国内资源，设计确定了材料的成分组成，制定了合理的铸造、热处理工艺，成功地研制了适合我国煤质特点的高铬白口铸铁磨辊．试验运行结果表明，同样工况条件下，所研制的高铬白口铸铁磨辊的耐磨寿命比进口镍硬Ｎ＃铸铁提高５０％以上，且成本降低，经济效益十分可观．