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1.
Hongsug Oh Sunghak Lee Jaeyoung Jung Sangho Ahn 《Metallurgical and Materials Transactions A》2001,32(3):515-524
The objective of this study is to investigate the correlation of microstructure with wear resistance and fracture toughness
in duocast materials that consisted of a high-chromium white cast iron and a low-chromium steel as the wear-resistant and
ductile parts, respectively. Different shapes, sizes, volume fractions, and distributions of M7C3 carbides were employed in the wear-resistant part by changing the amount of chromium and molybdenum. In the alloys containing
a large amount of chromium, a number of large hexagonal-shaped primary carbides and fine eutectic carbides were formed. These
large primary carbides were so hard and brittle that they easily fractured or fell off from the matrix, thereby deteriorating
the wear resistance and fracture toughness. In the alloys containing a smaller amount of chromium, however, a network structure
of eutectic carbides having a lower hardness than the primary carbides was developed well along solidification cell boundaries
and led to the improvement of both wear resistance and toughness. The addition of molybdenum also helped enhance the wear
resistance by forming additional M2C carbides without losing the fracture toughness. Under the duocasting conditions used in the present study, the appropriate
compositions for wear resistance and fracture toughness were 17 to 18 pct chromium and 2 to 3 pct molybdenum. 相似文献
2.
Effects of Rare Earths and Al on Structure and Performance of High Chromium Cast Iron Containing Wolfram 总被引:2,自引:1,他引:2
High chromiumcast ironis ani mportant grade ofwear-resistant material.It exhibits high hardness,ex-cellent wear resistance,andlowdeflection onrupture.Moreover,combined properties of high chromiumcastiron are better than that of other white cast irons.Therefore,it has many applications[1~4]in concrete,electric power,mine,metallurgy,and especially ap-plicationin ball mill with large diameter subjected toheavy i mpact loading[5].However,the brittle natureof this material often causesfailure under… 相似文献
3.
M 2highspeedsteel (M 2steel)isamaterialwidelyusedintoolsanddies[1,2 ] .M 2steelischarac terizedbyalongsolidificationrangeandcomplexeu tecticreactions ,whichresultsinsegregationofalloy ingelementsandformationofseveraldifferenttypesofcarbidesduringsolidification[3,4 ] .Forconventionallyprocessedhigh speedsteels ,itisinevitablethatacoarsecarbidenetworkwillbeformedduringsolidifi cation .Coarseprimarycarbidestendtoresultinun evencarbidebandsdistributionafterasubstantialamountofhotprocessing[5] .Ma… 相似文献
4.
《钢铁冶炼》2013,40(8):607-611
AbstractTo improve the toughness of hypereutectic high chromium cast iron, the morphology of the primary carbides were improved by the slope cooling body method, a semisolid forming process. The semisolid specimens were prepared under different forming techniques, and the microstructure, impact toughness and wear resistance were studied. The results indicate that the morphology of primary carbide is improved, impact toughness initially increases then remains constant as the semisolid forming temperature increases, impact toughness was improved, but wear resistance was reduced. 相似文献
5.
Chang Kyu Kim Sunghak Lee Jae-Young Jung 《Metallurgical and Materials Transactions A》2006,37(3):633-643
The objective of this study is to investigate effects of heat treatment on wear resistance and fracture toughness in duo-cast
materials composed of a high-chromium white cast iron and a low-chromium steel as a wear-resistant part and a ductile part,
respectively. Different size, volume fraction, and distribution of M7C3 carbides were employed in the wear-resistant part by changing the amount of chromium, and the volume fraction of martensite
in the austenitic matrix was varied by the heat treatment. In the alloys containing a small amount of chromium, an interdendritic
structure of eutectic M7C3 carbides was formed, and led to the improvement of wear resistance and fracture toughness. After the heat treatment, the
selective wear of the matrix and the cracking or spalled-off carbides were considerably reduced since the hardness difference
between carbides and matrix decreased by the increase in the matrix hardness, thereby leading to the improvement of the wear
resistance. However, the fracture toughness of the heat-treated alloys was lower than that of the as-cast alloys because the
matrix containing a considerable amount of martensite did not effectively prevent the crack propagation. 相似文献
6.
The unlubricated sliding wear test of high chromium white cast irons (HCCIs) was conducted using a pin-on-disc configuration under different heat treatments and different hardnesses of the counterface. With the increase of counterface hardness (20?HRC–47?HRC–54?HRC), the mass loss of the sample first increases then decreases. When the counterface hardness is 20?HRC, adhesion wear mainly takes place between the high chromium cast iron and the surface of 1045 steel. When the hardness is 47 or 54?HRC, first HCCI’ matrix wear takes place, then carbide bump flakes under alternating stress. The mass loss of the counterface decreases with the increase of hardness for the same sample. The mass loss of quenching, once tempering and twice tempering sample decreases gradually for the same counterface hardness, but fluctuation of the samples’ surface increased. The disc material is always softer than the pin material and results in a severe wear regime operation. 相似文献
7.
Effect of Heat Treatment on Structure and Wear Re- sistance of High Chromium Cast Steel ContainingBoron 总被引:1,自引:0,他引:1
The microstructure, mechanical properties and wear resistance of high chromium cast steel containing boron after different heat treatments were studied by means of the optical microscopy (OM), the scanning electron microscopy (SEM), X-ray diffraction (XRD), hardness, impact toughness, tensile and pin-on-disc abrasion tests. The results show that as cast microstructures of boron-free high chromium steel consist of martensite and a few (Cr, Fe)_7C_3 carbide, and the macro-hardness of boron-free high chromium steel is 55-57 HRC. After 0.5 mass% B was added into high chromium cast steel, as-cast structure transforms into eutectic (Fe, Cr)2B, (Cr, Fe)7 (C, B)a and martensite, and the macro-hardness reaches 58-60 HRC. High temperature quenching leads to the disconnection and isolated distribution of boride, and there are many (Cr,Fe)_23 (C,B)_6 precipitated phases in the quenching structure. Quenching from 1050 ℃, high chromium steel obtained the highest hardness, and the hardness of high chromium cast steel containing boron is higher than that of boron-free high chromium steel. The change of quenching temperature has no obvious effect on impact toughness of high chromium steel, and the increase of quenching temperature leads to tensile strength having an increasing tendency. At the same quenching temperature, the wear resistance of high chromium cast steel containing boron is more excellent than that of boron-free high chromium steel. High chromium cast steel guide containing boron has good performance while using in steel bar mill. 相似文献
8.
Baotong Lu Jingli Luo Stefano Chiovelli 《Metallurgical and Materials Transactions A》2006,37(10):3029-3038
The corrosion and wear resistances of a series of cast chromium white irons (CWIs) were evaluated using electrochemical and
low stress sliding abrasion tests. The results show clearly that corrosion resistance of these materials is largely dependent
on the quantity of chromium in the matrix, while wear resistance is mainly controlled by the volume fraction of chromium carbides.
Based on theoretical analysis, a wear/corrosion performance map is established to identify alloy compositions that may be
suited for erosion/corrosion conditions. 相似文献
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11.
为了提高材料在水泥混凝土搅拌和输送工况下的使用性能,以新研制的耐磨耐蚀铸铁为对象,采用复合变质处理的方法研究了变质剂加入量对该试验合金铸铁组织、力学性能和耐腐蚀磨损性能的影响。研究结果表明,复合变质处理可以细化耐磨耐蚀铸铁基体组织、消除柱状枝晶,改善碳化物形态、尺寸及分布,使碳化物由变质前的粗大棒条状变为均匀分布的短棒状和颗粒状,消除了粗大片状碳化物对材料基体的危害,使耐磨耐蚀铸铁的性能得到改善。变质剂加入量增加,耐磨耐蚀铸铁的冲击韧度和耐磨耐蚀性能均有较大提高。与变质前相比,加入0.25%和0.50%复合变质剂处理的试验合金铸铁,其冲击韧度和相对耐腐蚀磨损性能分别提高了22.9%、58.3%和16%、23%,基体硬度略有降低,达到了预期效果。 相似文献
12.
Yogesh Kumar Singla Rahul Chhibber Navneet Arora Karanpreet Singh Kishore Khanna 《Transactions of the Indian Institute of Metals》2017,70(6):1555-1561
The present paper describes an investigation aimed at evaluating the microstructural and dry sliding adhesive wear characteristics of Fe–xCr–4Mn–3C hardfacing alloys applied through shielded metal arc welding. The effect of chromium addition on the microstructure of hardfacings was carried out by using optical microscope, field emission scanning electron microscope and X-ray mapping. Dry sliding wear tests were performed on a pin-on-disc wear tribometer. From the experimental results, it was observed that the primary carbides were refined and increased with the increase of chromium content. The morphology of carbides revealed that the primary carbides were rod shaped. The increased chromium content was also found to be beneficial to enhance hardness and wear resistance of hardfacings. The correlation between hardness and wear resistance exhibited the reliability of hardness as an indicator of the wear performance of hardfacings. 相似文献
13.
Gray cast irons were inoculated with FeSi75+RE and FeSi75+Sr inoculants. The changes of apex angle of the drills before and af-ter being used were used to evaluate machinability of gray cast irons. Effect of FeSi75+RE and FeSi75+Sr inoculants on mechanical proper-ties, machinability and sensibility of gray cast iron used in cylinder block were investigated. Experimental results showed that gray cast iron treated with 60%FeSi75+40% RE inoculants exhibited tensile strength consistently at about 295 MPa along with good hardness and im-proved metallurgical quality. While gray cast iron inoculated with 20%FeSi75+80% Sr inoculants exhibited the best machinability, the low-est cross-section sensibility and the least microhardness difference. The tool flank wear of the drill increased correspondingly with the in-crease of the microhardness difference of the matrix, indicating the great effect of homogeneity of the matrix on the machinability of gray cast iron. 相似文献
14.
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… 相似文献
15.
Two medium carbon low-alloy MnSiCrB cast steels containing different Cu contents (0.01 wt pct and 0.62 wt pct) were designed,
and the effect of Cu on the mechanical properties and corrosion–abrasion wear behavior of the cast steels was studied. The
results showed that the low-alloy MnSiCrB cast steels obtained excellent hardenability by a cheap alloying scheme. The microstructure
of the MnSiCrB cast steels after water quenching from 1123 K (850 °C) consists of lath martensite and retained austenite.
After tempering at 503 K (230 °C), carbides precipitated, and the hardness of the cast steels reached 51 to 52 HRC. The addition
of Cu was detrimental to the ductility and impact toughness but was beneficial to the wear resistance in a corrosion–abrasion
wear test. The MnSiCrB cast steel with Cu by the simple alloying scheme and heat treatment has the advantages of being high
performance, low cost, and environmentally friendly. It is a potential, advanced wear-resistant cast steel for corrosion–abrasion
wear conditions. 相似文献
16.
Sajjad Jafari 《钢铁研究学报(英文版)》2012,19(4):42-50
Abstract: Wear properties of two different crushers used for grinding raw materials of cement industry are compared using pin-on-disk wear test. The wear test was carried out with different loads on a pin. Abrasive wear behavior of two alloys was evaluated by comparing mass loss, wear resistance, microhardness and friction coefficient. The microstructure of the specimens was detected using optical microscope. The results showed that abrasive wear of high chromium cast iron is lower than that of Hadfield steel. Due to the presence of M7C3 carbides on the high chromium cast iron matrix, impact crushers exhibited higher friction coefficient. 相似文献
17.
导板是线材轧机的关键备件,要求有优良的耐磨性,抗断裂性,抗粘钢性和热冲击抗力,常用高镍镍钢导板和高铬铸铁导板满足不了上述要求,使用寿命短,更换频繁,降低了轧机作业率,增大了工人劳动强度,高速钢具有硬度高,红硬性好和耐磨性好等特点,但铸造高速钢脆性大,通过调整高速钢成分和采用RE-Mg-Ti复合变质处理,可改变共晶碳化物的形态和分布,使高速钢冲击韧性大幅度提高,变质处理高速钢导板使用中不粘钢,不断裂,耐磨性明显优于普通导板。 相似文献
18.
以一种自行设计的NM500级别耐磨钢为研究对象,利用冲击磨损试验,分析了深冷处理对其组织性能和磨损行为的影响。结果表明,NM500耐磨钢经深冷处理后,抗拉强度、硬度和冲击韧性均有提高,在淬火+深冷+回火处理后,最佳的综合力学性能可达抗拉强度1 910 MPa、硬度523HB、冲击韧性24.3 J/cm2,此时试验钢组织主要为马氏体,有Nb和Ti的碳化物析出。深冷处理通过残余奥氏体向马氏体转变,减少了不稳定相的含量,提升了试验钢的力学性能,从而使淬火+深冷+回火处理后的试验钢具有更高的耐磨性,此时的磨损机制以磨粒磨损为主,磨损形貌主要为犁沟、犁皱。而未经深冷处理的淬火+回火处理试验钢磨损机制以黏着磨损为主,磨损形貌主要为剥落坑和切削。 相似文献
19.
Yi-Wa Luo Han-Jie Guo Xiao-Lin Sun Jing Guo Fei Wang 《Metallurgical and Materials Transactions A》2018,49(12):5976-5986
AISI M42 high-speed steel is prone to fracture as a result of its brittle martensitic microstructure together with abundant carbides located at the grain boundaries. In this study, a series of property tests including hardness, impact toughness, and wear loss were performed to study the effect of tempering conditions on the mechanical properties of AISI M42 high-speed steel over holding time ranging from 1 to 20 hours. The effects of the tempering time on the characteristics and growth of carbides were also investigated. The results indicated that carbides in the experimental steels were obviously coarsened when the tempering time exceeded 4 hours. The dimension of the carbides increased, while the volume fraction decreased with the increasing tempering time, and the grain sizes were significantly augmented due to the reducing of small carbides. Moreover, the dislocation density decreased with the increasing tempering time, which led to the reducing of the yield stress of high-speed steel. An appropriate holding time (4 hours) resulted in fine-scale secondary carbides and a smaller grain size, which efficiently improved the impact toughness and wear resistance simultaneously. Nevertheless, a prolonged tempering time (>?4 hours) promoted the coarsening and coalescence of carbides, which were detrimental to the impact toughness and wear resistance. Consequently, the formation of fine-scale secondary carbides is the major influential factor to improve both the wear resistance and impact toughness. 相似文献