Research on Thermal Wear of Cast Hot Forging Die Steel Modified by Rare Earths

Thermal wear of cast hot-forging die steel modified by rare earths（RE） was studied and compared with commercially used die steels. The function of RE and the mechanism of thermal wear of cast steel modified by RE were discussed. The results showed that with increasing content of RE, the wear rate of cast steel reduced at first and then increased. By adding 0.05% （mass fraction） RE, the cast hot-forging die steel with optimum thermal wear resistance was obtained, which was better than that of H13 and 3Cr2WSV. The large amount of coarse inclusions, （RE）2O2S, resulted from excessive RE, which obviously deteriorated thermal wear resistance. The mechanism of thermal wear of the modified cast die steel is oxidation wear and oxide fatigue delamination. The wear debris are lumps of Fe2O3 and Fe3O4.     

Effects of Light and Heavy Rare Earths on Anti-Degradation of Nodular Cast Iron

The effects of rare earths with different contents on anti-degradation of Y base heavy rare earths-magnesium and cerium base light rare earths-magnesium nodular cast iron were studied. Curves of the relationship between the spheroidization grade of liguid iron treated by different nodulizers and holding time were obtained. The results show that the more the remains of the rare earth, the longer the anti-degradation time, the liquid iron was treated either by Y-Mg-Si or by Ce-Mg-Si nodulizer. When the rare earth remains are above certain quantity, the spheroidization grade starts to decline. When liquid iron treated by either Y-Mg-Si or Ce-Mg-Si nodulizer with proper remains of rare earths about 0.04% 0.06%（mass fraction）, the anti-degradation is the best, and the remains of Mg being about 0.04% -0.07% （mass fraction）. Rare earths-Mg nodulizer with moderate RE remains is better than that of Mg-Si nodulizer in anti-degradation property. However, Y-Mg-Si nodulizer with moderate remins of Re is better than Ce-Mg-Si nodulizer. Sometimes Ce-Mg- Si nodulizer can be used for the production of heavy section nodular cast iron.     

Effect of Rare Earths—Treated Glass Fiber on Impact Wear—Resistance of Metal—Plastic Multilayer Composites

The friction and wear properties under impact load and dry friction conditions of metal-plastic multilayer composites fillde with glass fiber,treated with rare earth elements,were investigated,The worn surfaces were observed and analyzed by scanning electron microscopy(SEM).It shows that applying rare earth elements surface modifier to treat the glass fiber surface can enhance the interfacial adhesion between the glass fiber and polytetrafluoroethylene (PTFE),as well as promote the interface properties of the composites,This helps to form a uniflrmly distributed and high adhesive trandfer film on the counterface and abate the friction between the composite and the counterface,As a result,the wear of compostite is greatly reduced.The composite exhibits execllent friciton properties and impact wear-resistance.     

不同稀土掺杂聚苯乙烯力学性能研究

选择了几种功能不同的Pr，Eu，Gd，Th，Dy，Ho和Er的三异丙氧基化合物与苯乙烯本体聚合获得稀土掺杂聚苯乙烯，采用ESEM，DMTA，冲击强度测试研究了不同稀土对聚合物力学性能的影响，结果表明不同稀土引入聚苯乙烯中均能使韧性得以提高，它们的力学性能与稀土的原子序数、原子半径大小有关。     

Study on Heterogeneous Nuclei in Cast H13 Steel Modified by Rare Earth

Ｔｈｅｐｏｏｒｍｅｃｈａｎｉｃａｌｐｒｏｐｅｒｔｉｅｓｏｆｃａｓｔｍａｔｅｒｉａｌｓ ,ｅｓｐｅｃｉａｌｌｙｌｏｗｔｏｕｇｈｎｅｓｓ ,ｉｓａｍａｉｎｆａｃｔｏｒｌｉｍｉｔｉｎｇｔｈｅａｐｐｌｉｃａｔｉｏｎｏｆｐｒｅｃｉｓｅｃａｓｔｄｉｅｓ[1] .ＴｈｒｏｕｇｈｔｈｅｍｏｄｉｆｉｃａｔｉｏｎｏｆｃａｓｔＨ1 3ｓｔｅｅｌｂｙＲＥ ,ｔｈｅｄｅｎｄｒｉｔｅｓｅｇｒｅｇａｔｉｏｎｏｆＣＨ1 3ｓｔｅｅｌｗａｓｉｍｐｒｏｖｅｄａｎｄｇｒａｉｎｂｏｕｎｄａｒｙｃａｒｂｉｄｅｗａｓａｌｓｏｕｎｄｅｒｃｏｎｔｒｏｌ.Ａｃｃ…     

Effects of Rare Earth Elements on Corrosive Wear Behaviour of Cast Cr-Mn-N Stainless Steel in Dilute Sulphuric Acid

ＥｆｅｃｔｓｏｆＲａｒｅＥａｒｔｈＥｌｅｍｅｎｔｓｏｎＣｏｒｒｏｓｉｖｅＷｅａｒＢｅｈａｖｉｏｕｒｏｆＣａｓｔＣｒＭｎＮＳｔａｉｎｌｅｓＳｔｅｌｉｎＤｉｌｕｔｅＳｕｌｐｈｕｒｉｃＡｃｉｄＤｉｎｇＨｕｉ（丁晖），ＹｕａｎＧｕａｎｇｙｉｎ（袁广银），...     

Effect of Rare Earth Elements on Isothermal Transformation and Microstructures in 20Mn Steel

The effect of rare earth elements on the isothermal transformation and microstructures in 20Mn steel is in-vestigated by means of metallography and dilatometry.Rare earth elements decrease both the incubation periodof pro-eutectoid ferrite and the rate of pearlitic transformation.In addition,rare earth elements play a role ofreducing needle-like ferrite and the amount of pearlite,densifing the lamellar space of pearlite and enhcingsegregation of carbide in granular bainite.It is suggested that rare earth elements may decrease the interfacialenergy of grain boundary and interphase,hinder the diffusion of carbon atoms and form rare earth carbides withhigh melting point which reduce the carbon content in austenite.     

Effect of Rare Earths on Properties of BNbRE Rail Steel

The development and properties of BNbRE rail steel and the effect of RE on rail steel were studied. The results show that the properties of rail steel (δb ≥980 MPa, δ5≥ 8 % ) can be improved by adding RE and niobium and adjusting the content of C, Si and Mn in steel. At the same time, the abrasion resistance, contact fatigue and fatigue property of BNbRE rail steel are excellent. It also shows that RE in rail steel has the functions of purifying steel, modifying inclusion and micro-alloy action effect. The improved steel-making process enhances the quality of molten steel. Although the content of RE is low, excellent properties of BNbRE rail steel are achieved.     

Effects of Rare Earths and Al on Structure and Performance of High Chromium Cast Iron Containing Wolfram

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…     

稀土对钢轨钢接触疲劳的影响

利用接触疲劳磨损试验机械钢轨／车轮接触疲劳作用,了钢轨钢接触疲劳表面区剖面的形貌,显微结构和硬度。结果表明,稀土可延缓钢表面疲劳裂纹的萌生和扩展,推迟表面剥离,减小裂纹贯穿角和裂纹稳定贯穿,缩小塑性化形范围和改善表面加工硬化效果。     

Mn2钢低温韧性变化规律研究

对Mn2钢在不同热处理工艺、不同试验温度和不同试样状态下的冲击韧性进行了详细的分析,结果表明:CM690钢在900℃保温90 min水冷淬火,600℃保温90 min水冷回火,在保证钢材的强度满足要求的情况下,可获得良好的韧性;淬火水温超过30℃时,因钢的淬透能力下降,会强烈地降低钢的强度和韧性;钢中加入0.015%~0.025%的Ti,提高冲击韧性值35~40 J;对于CM490钢,若轧后空冷或堆冷,由于冷却速度较低,会获得铁素体+珠光体+贝氏体的混合组织,不利于提高钢材的韧性,而正火后其组织为铁素体+贝氏体,其冲击值比前两种状态高3~5倍。     

Effect of Rare Earth Composite Modification on Microstructure and Properties of a New Cast Hot-Work Die Steel

The effects of RE modification on structure and the properties of a new cast hot-work die (CHD) steel were investigated. The grains of the CHD steel are refined by RE modification. With the increase of RE addition, both grain size and inclusion amount are reduced. Appropriate amount of RE results in decrease in inclusion amount and formation of spheroidal inclusions uniformly - distributed in steel, so that the morphology and distribution of inclusions are improved. RE composite modification favors the formation of bainite, austenite and fine lath martensite with dense dislocation. When the residual RE content reaches 0.02 %, no obvious changes in strength and hardness are found, while fracture toughness and threshold of fatigue crack growth are increased. The impact toughness, elongation and reduction of cross sectional area are increased by a factor of two, and thermal fatigue resistance is also improved.     

喂稀土丝处理16Mn钢的试验研究

在实验室内模拟生产在结晶器丝的工艺，对１６ｎｍ钢进行稀土处理试验研究。检验了稀土加入量对钢中氧含量、钢的晶粒度、钢中夹杂物状况以及对钢材冲击韧性的影响。提出在结晶器内喂稀土丝的工艺及稀土的合适加入量为０．１０％、１．１２％。     

稀土对Zn-Al-Cu合金机械性能的影响

研究了不同铝铜含量锌合金的强度,并加入适量的Ti,B,RE,Mg等元素,得出模具用锌合金的最佳铝铜含量（%,质量分数）分别为Al14%,Cu10%。重点研究了不同稀土含量（0,0.05%,0.1%,0.2%,0.4%,0.6%）对锌合金的影响,每种合金分别采用空冷和水冷两种冷却方式,结果表明,稀土含量为0.4%的合金为模具用锌合金的最佳稀土含量,其中以水冷方式为最佳的冷却方式。     

稀土导电铝合金的铸态组织和相组成

本文利用光学显微镜、扫描电镜、Ｘ射线衍射仪等，研究了Ｌａ、Ｃｅ对工业纯铝铸态组织和相组成的影响。结果表明，Ｌａ、Ｃｅ能细化工业纯铝的铸态组织，并和Ｆｅ、Ｓｉ等元素结合生成了二元或三元稀土化合物相。     

Room-Temperature Mechanical Properties of Rare Earths Reinforced MoSi_2 Material

Ｉｎｔｅｒｍｅｔａｌｌｉｃｍｏｌｙｂｄｅｎｕｍｄｉｓｉｌｉｃｉｄｅ(ＭｏＳｉ2 )ｉｓａｎａｔｔｒａｃｔｉｖｅｃａｎｄｉｄａｔｅｍａｔｅｒｉａｌｆｏｒｈｉｇｈｔｅｍｐｅｒａｔｕｒｅｓｔｒｕｃｔｕｒａｌａｐｐｌｉｃａｔｉｏｎｓｂｅ ｃａｕｓｅｏｆｉｔｓｈｉｇｈｍｅｌｔｉｎｇｐｏｉｎｔ(2 0 3 0℃ ) ,ｌｏｗ ｅｒｄｅｎｓｉｔｙ ,ｈｉｇｈｔｈｅｒｍａｌｃｏｎｄｕｃｔｉｖｉｔｙａｎｄｅｌｅ ｖａｔｅｄｏｘｉｄａｔｉｏｎｒｅｓｉｓｔａｎｃｅａｎｄｃｏｒｒｏｓｉｏｎｒｅｓｉｓ ｔａｎｃｅ .ＭｏＳｉ2 ｉｓｄｉｍｏｒｐｈ…     

Effect of Austempering on the Structures and Performances of Cast High Carbon Si‐Mn Steel

The effects of austempering on the microstructures and mechanical performances of cast high carbon silicon and manganese steel (HCSMS) containing 1.0 wt.%C‐2.5 wt.%Si‐1.5 wt.%Mn‐1.0 wt.%Cr‐0.5 wt.%Cu were studied. The test results show a plate‐like morphology of bainitic ferrite. Each plate of the ferrite is surrounded by a thin layer of retained austenite when the austempering temperature is low, whereas large blocky areas of retained austenite are observed when the temperature is higher. The amount of retained austenite in the bainitic structure increases with increasing isothermal quenching temperature. Austempering results in a significant improvement in the mechanical performances of HCSMS. The main effect of the austempering temperature on the mechanical performances is that hardness and strength are decreased and elongation, impact toughness and fracture toughness are increased with increasing temperature. Cast HCSMS has excellent comprehensive mechanical performance when austenized at 593K.     

Effects of Rare Earths on Properties and Microstructure of Automotive Friction Materials

Rare earth compounds as modifiers used widely in modern friction materials can enhance the interracial binding of constituents of materials and improve the comprehensive properties of materials evidently. However, there are still few reports on application of rare earth in automotive friction materials. In order to study the effect mechanism of rare earths in friction materials, a rare earth compound was selected as additive and the effects of materials doped with or without rare earth on friction and wear properties of materials were studied. The microstructure and worn surface morphology were observed by scanning electron microscopy and the macro performance was discussed. Worn surface element constitution of materials was analyzed by energy dispersive spectroscopy. Effect mechanism of rare earths on friction and wear behaviors of friction materials were discussed. The results show that doping rare earths in friction materials can stabilize friction Coefficient, lower the wear rate of materials and increase the impact strength of materials. The flexibility and fracture resistance of materials is greatly improved. Worn surface of materials doped with rare earth is compact and the surface adhesion is greatly enhanced.     

Study of Rare Earths in Pipeline Steel

ＳｔｕｄｙｏｆＲａｒｅＥａｒｔｈｓｉｎＰｉｐｅｌｉｎｅＳｔｅｌＬｉｕＹｏｎｇｈｕａ（刘勇华），ＹｅＷｅｎ（叶文），ＬｉｎＱｉｎ（林勤）ＣｈｅｎＮｉｎｇ（陈宁）（ＤｅｐａｒｔｍｅｎｔｏｆＰｈｙｓｉｃａｌＣｈｅｍｉｓｔｒｙ，ＵｎｉｖｅｒｓｉｔｙｏｆＳｃｉ...     

稀土对低合金耐磨铸钢组织和性能的影响

采用扫描电镜分析,硬度测试和摩擦性能测试等手段,研究了稀土对低合金耐磨铸钢组织和性能的影响。结果表明,在低合金耐磨铸钢中添加0.15%稀土,可细化合金铸态组织,增加铸态组织中的铁素体数量,减少珠光体数量,同时可细化热处理后合金的贝氏体组织,使铁素体形态和大小分布均匀,马氏体数量减少。添加稀土后可使铸态合金硬度提高9.4%,摩擦系数由0.136 9减小为0.081 9。