球铁中加入B,Cr,Mo,Cu合金元素的生产实践

从1983年以来,我们采用普通球铁中加入B、Cr、Mo、Cu合金元素,以提高材质机械性能的方法,对不同要求的易损件进行了生产实践,生产和使用结果表明,加入合金元素后的球铁易损件的平均使用寿命是原普通球铁的2～3倍,取得了明显的经济效益。 1.合金元素对性能影响及使用特点据有关资料表明,铁水中加人微量B、Cr、Mo、Cu合金元素后,可显著细化组织,提高强度、耐磨性和耐蚀性。其中B元素在基体中以     

高综合性能球铁的研制

通过选用合理的化学成分，严格控制铁液硫、磷的含量，在铁液中适当加入Cu、Mo合金元素，选用低稀土球化剂．并使用盖包法球化处理工艺，采用复合孕育处理工艺，进行部分奥氏体化热处理，成功研制出高强度且具有较高韧性的球铁曲轴。     

球墨铸铁QT850-4多缸曲轴的研制

使球铁曲轴材料的性能达到QT850-4要求,采取了下列技术措施:①采用电炉熔化铁液,进行吹氮脱硫获得高温、低氧化、低硫的优质铁液;②严格控制铁液的化学成分,在铁液中适当加入Cu、Mo合金元素,有利于改善曲轴的金相组织,细化晶粒;③选用低稀土球化剂FeSiMg8RE3;④使用盖包法球化处理工艺,用多元微量复合孕育剂进行孕育处理;⑤进行部分奥氏体化热处理工艺,研制出了高强度且具有一定韧性的球铁曲轴.     

QT850-4球铁曲轴的试制

通过合理选择铁液的化学成分,严格控制铁液的硫、磷含量,在球铁中添加Cu、Mo元素,选用低稀土球化剂,采用盖包法球化处理工艺及复合孕育工艺,并且进行部分奥氏体化热处理工艺,研制出了高品质的球墨铸铁件,其抗拉强度和伸长率分别超过850MPa和4%.     

关于提高球墨铸铁焊缝强度问题的探讨

本文通过试验和分析,探讨了球墨铸铁正火焊缝强度较低的原因。指出,焊缝快速冷却的固有特征,使焊缝中存在大量、细小的石墨球,为基体中的碳在正火冷却时向石墨球表面扩散沉淀,创造了极好的条件,使焊缝基体中的碳含量降低,促使奥氏体向铁素体转变。文中还指出,在焊缝中加入适当的Cu、Mo、Mn、Ni、Sn等元素使基体合金化,是增加正火焊缝中的珠光体含量和提高强度的有效方法,并可达到与珠光体球墨铸铁(如QT60-2)等强度的要求。     

合金元素对球铁珠光体稳定性的影响

为了研究在厚大断面球墨铸铁中合金元素对珠光体稳定性的影响,制备了基体为100%珠光体的球墨铸铁试样。采用不同的退火工艺及退火时间模拟厚大断面球铁内部缓慢的冷却过程,通过分析珠光体分解为铁素体的含量,来研究Cu、Ni、Mo、Sn、Sb对珠光体稳定性的影响。结果表明,球铁中Ni、Mo含量的增加会对珠光体的稳定性产生不利影响,合金元素Cu、Sn、Sb含量的增加能对珠光体的稳定性起到有利的作用。     

Mo、Cu对高铬铸铁凝固组织和亚临界热处理硬化行为的影响

研究了Mo和Cu对高铬铸铁凝固组织和亚临界热处理硬化行为的影响。研究表明，添加Mo和Cu可以使高铬铸铁的凝固组织获得更多的残留奥氏体。含有Mo和Cu的高铬铸铁在亚临界热处理过程中有明显的二次硬化现象。由于Mo是强碳化物形成元素与碳原子之间有强的相互吸引作用，阻碍碳原子在凝固冷却时碳从奥氏体向液相扩散，使共晶奥氏体的碳含量较高，导致奥氏体的Ms点降低，使得铸态组织获得更多的残留奥氏体。固溶于奥氏体中的Cu对奥氏体中碳在亚临界热处理过程中的析出具有很强的阻碍作用，所以与没有添加Mo和Cu的高铬铸铁比较，添加Mo和Cu的高铬铸铁二次硬化峰的出现需要更高的温度或者更长的保温时间。     

ADI工艺对水平连铸球铁型材组织的影响

利用正交试验方法对φ172 mm的水平连铸球墨铸铁LZQT500-7型材的奥氏体化温度和时间、等温淬火温度及时间等ADI工艺参数进行对比研究,探讨了不同参数条件对该型材组织形貌的影响规律。结果表明,随着奥氏体化温度和等温淬火温度升高,基体中残余奥氏体含量增多;当奥氏体化温度较低时,适当延长保温时间有利于得到针状铁素体和残余奥氏体(奥铁组织),延长等温淬火时间有利于获得稳定残余奥氏体,并防止高碳奥氏体分解。     

铸态奥氏体—贝氏体蠕铁的试验研究

本文研究了铸态下直接获得奥氏体—贝氏体蠕铁时合金元素Mo、Ni、Cu的不同配比用原Si含量的高低对其组织和机性的影响。阐述了氏体—贝氏体蠕铁的组织、性能特征;给出了在干砂型中,采用中量合金化条件下的最大淬透壁序。     

正火处理对破碎铁素体球墨铸铁组织和性能的影响

为了提高球墨铸铁曲轴的强度和韧性,对铸态球铁进行不完全奥氏体化正火处理,在球铁基体内获得了珠光体及分散状的破碎铁索体组织.分析正火保温温度及保温时间对球墨铸铁组织和性能的影响,发现在奥氏体、铁素体和石墨的三相共存区内,随着保温温度的升高、保温时间的延长,正火后球铁基体中珠光体含量增加、铁素体含量下降,试样的强度、硬度呈上升趋势,韧性塑性有一定的下降.在860～870℃下保温1.5 h的曲轴,具有最佳的综合力学性能.     

Effect of C and Si on mechanical properties of austempered ductile iron

It is well known that ductile cast iron can be strengthened and toughened by austempering. The tensile strength and the fatigue strength of austempered ductile iron (ADI) are equal to those of forged steel. Previous studies have been aimed at establishing a suitable process to obtain both strength and toughness in ADI.^1,2 These studies focused on the effect of alloying such as Mo, Ni, Mn, Cu, etc. and the austempering conditions such as temperature and holding time. In this study, a new type of ADI with higher toughness and higher elongation was developed as compared with conventional ADI. A new type of ADI with a low carbon content was achieved by reducing the initial carbon content, long annealing and ordinary austempering. The suitable silicon content was found to be 2.5% and effective alloying was 0.25% Mo and 0.7% Cu to obtain maximum impact energy and elongation.     

Microstructure and Mechanical Properties of a Wear-Resistant As-Cast Alloyed Bainite Ductile Iron

An as-cast bainite ductile iron with excellent mechanical properties and wear resistance was fabricated by alloying and centrifugal casting method, and the alloyed chemical composition was optimized by using the thermodynamic software Thermo-Calc. By using optical microscopy, transmission electron microscopy, scanning electron microscopy, and X-ray diffraction, the microstructure of the as-fabricated bainite ductile cast iron was characterized pertinent to the elements distribution in matrix and features of ferrite and retained austenite. The results of mechanical properties test show that the hardness and compressive strength of this alloyed ductile iron are 52 HRC and 2,200 MPa, respectively. The ascast bainite ductile iron possesses highly abrasive wear resistance and the reason can be ascribed to the solid solution of the elements Si, Ni, Cu, and Mn in the austenite and the formation of carbides of elements Cr and Mo. The strength of bainite ductile iron is increased by the acicular bainitic ferrite in the matrix.     

EQ491铸态珠光体球墨铸铁连杆的研究

分析了铸态珠光体球墨铸铁的形成条件，利用正交试验确定了球墨铸铁连杆Si,Mn,Cu等元素的成分，通过研究碳当量对组织性能的影响，确定了C元素的成分。生产试验证明，铸态珠光体球墨铸铁连杆可替代进口可锻铸铁件。     

冲天炉生产铸态球铁QT700-2

介绍冲天妒熔制铁液获得铸态高强度球墨铸铁QT700-2的方法与生产过程,分析化学成分、脱硫、炉料选用、孕育、球化处理等对冲天炉熔炼获得高强度球墨铸铁的影响.实践表明,降低终硅量,添加Cu元素,优化球化处理工艺,并采用长效孕育剂,冲天炉可以稳定生产铸态QT700-2球铁.     

Influence of alloying elements Cu,Ni and Mo on mechanical properties and austemperability of austempered ductile iron

Abstract

Austempered ductile iron (ADI) is the most recent development in the nodular iron family. The austempering treatment produces a unique microstructure, ausferrite, which provides high mechanical strength combined with ductility, toughness, and good fatigue and wear resistance. The effect of alloying elements Cu, Ni and Mo on the mechanical properties and austemperability of ADI is reported. The mechanical strength and toughness decreased with the addition of Mo, but both wear resistance and austemperability increased with Mo content.     

奥-贝球铁的铸造原理及研究进展

奥-贝球铁具有高强度、高韧性、良好的耐磨性、耐热性、耐蚀性以及优良的铸造性能等特点,本文中概述了奥-贝球铁的铸造原理,详细介绍了碳、硅、锰、硫、磷、钼、镍、铜、钒、铌等合金元素及热处理工艺对奥-贝球铁性能的影响.并简要介绍了第四届国际奥-贝球铁学术会议的内容,对国内外奥-贝球铁的研究及生产应用作了综述,最后展望了奥-贝球铁的应用前景.     

高强度厚大断面球墨铸铁件的熔炼工艺

为生产高强度厚大断面球墨铸铁件,对熔炼原材料、铁液化学成分和球化孕育处理技术进行了分析,确定了球铁熔炼工艺的主要控制要素,采用高温正火热处理工艺保证材料均匀一致的基体组织。试制阶梯试块的力学性能和显微组织均符合技术要求,从而保证高强度厚大断面球墨铸铁件的正常生产。     

金属型对灰铸铁和球铁力学性能的影响研究

采用铜合金金属型和铸铁金属型浇注灰铸铁和球铁Y形试块，加入不同量的Mn、Ti、Cu和Sn，研究金属型材料和添加合金对灰铸铁和球铁抗拉强度和疲劳强度的影响。结果发现：与采用铸铁金属型浇注相比，未加合金、采用铜合金金属型浇注的灰铸铁和球铁的力学性能略高。采用铜合金铸型浇注时，由于冷速较快，使石墨和基体组织细化的作用较强，添加合金元素改善力学性能的作用较为明显，而且反复浇注时，铜合金金属型的热应力较小。因此，灰铸铁和球铁采用铜合金金属型铸造比采用铸铁金属型有利。     

铸态贝氏体球铁齿轮的研制

选择适当的化学成分,用铜和钼配合进行合金化,采取一定的工艺手段,可以获得铸态贝氏体球铁,其基体组织主要由羽状贝氏体和残留奥氏体构成,具有良好的综合力学性能.目前已在减速机齿轮中得到应用.     

Effect of Cu content on microstructures and mechanical properties of ADI treated by twostep austempering process

The effect of Cu content on the microstructures and mechanical properties(yield strength,ultimate tensile strength,impact energy,fracture toughness) of austempering ductile iron(ADI) treated by two-step austempering process were investigated. High Cu content in nodular cast irons leads to a significant volume fraction of retained austenite in the iron after austempering treatment,but the carbon content of austenite decreases with the increasing of Cu content. Moreover,austenitic stability reaches its maximum when the Cu content is 1.4% and then drops rapidly with further increase of Cu. The ultimate tensile strength and yield strength of the ADI firstly increases and then decreases with increasing the Cu content. The elongation keeps constant at 6.5% as the Cu content increases from 0.2% to 1.4%,and then increases rapidly to 10.0% with further increase Cu content to 2.0%. Impact toughness is enhanced with Cu increasing at first,and reaches a maximum 122.9 J at 1.4% Cu,then decreases with the further increase of Cu. The fracture toughness of ADI shows a constant increase with the increase of Cu content. The influencing mechanism of Cu on austempered ductile iron(ADI) can be classified into two aspects. On the one hand,Cu dissolves into the matrix and functions as solid solution strengthening. On the other hand,Cu reduces solubility of C in austenite and contributes more stable retained austenite.