奥贝球铁的热稳定性

测定了奥贝球铁在连续缓慢和加热条件下的回火曲线，分析讨论了其回火过程中的变化特点，研究了合金元素Ｎｉ不同加入量，等温淬火工艺对奥贝球铁热稳定性的影响及其影响机制。结果表明，在贝氏体第一阶段转变结束时，奥贝球铁表现出较好的热稳定性，合金元素Ｎｉ加入量的增加使奥贝球铁的热稳定必降低，奥氏体化温度和等温淬火温度提高可使奥贝球铁的稳定性提高。     

浅谈奥贝球铁及其应用

介绍了奥贝球铁的发展历程和使用价值,阐述了化学成分对奥贝球铁力学性能的影响,分析了奥贝球铁等温淬火热处理规范及工艺过程,对具有高强度、高韧性的奥贝球铁材料的工业应用情况作了介绍,并提出了一些促进奥贝球铁产业化发展的建议.     

用高锰生铁生产奥贝球铁的研究及应用

在分析在锰对奥贝球铁组织和性能的影响的基础上，研究了用高锰生铁生产奥贝球铁的方法。结果表明，采用强化孕育处理等工艺，可使含锰０．７％左右的奥由球铁具有较理想的金相组织和力学性能。     

奥贝球铁汽车齿轮的开发研究及其应用

对奥贝球铁发动机齿轮的铸造工艺进行了试验研究，并对奥贝球铁发动机齿轮的金相组织和力学性能进行了检测分析，确定了合理的铸造和热处理工艺规程，结果证明，该工艺是可行的。     

奥贝球铁汽车正时齿轮应用研究

研究了用连铸球铁棒材制备奥贝球铁汽车正时齿轮的生产工艺。结果表明，用含Ｍｎ达０．７２％的球铁棒材，经合适的等温淬火处理后，能获得较理想的奥贝球组织和较高的综合力学性能。     

奥贝球铁汽车齿轮的开发研究及其应用

对奥贝球铁发动机齿轮的铸造工艺进行了试验研究，并对奥贝铁球发动机齿轮的金相组织和力学性能进行了检测分析，确定了合理的铸造和热处理工艺规程，结果证明，该工艺是可行的。     

奥贝球铁蜗轮在阀门电动装置上的应用

分析了热处理工艺中奥氏体化温度和时间、等温淬火温度和时间对奥贝球铁性能的影响。确定了阀门驱动装置用奥贝球铁材料蜗轮的生产工艺。通过装机试验验证,研制的奥贝球铁材料蜗轮满足使用性能要求,降低了生产成本。     

锰对奥贝球铁性能的影响

奥贝球铁能够实现高硬度的同时具有较高的韧性，适用于一定冲击条件下耐磨零件的工作要求。研究了高硅条件下锰对奥贝球铁性能的影响，为该材料的应用提供了试验基础。     

降低柴油机噪音的球铁齿轮研制成功

一种能有效降低柴油机整机噪音的“奥贝球铁齿轮”，日前在一汽无锡柴油机厂通过评审，这种球铁齿轮将代替原来的钢齿轮。 “奥贝球铁齿轮”具有优异的综合机械性能，用其制造的受力较为复杂的齿轮等零件重量轻、吸震好、噪音小，受到国内外专家的关注。一汽无锡柴油机厂从去年开始进行“奥贝球铁齿轮”代替调质钢齿轮的实验研究.实验结果表明，整机降低噪音１．９２ｄＢ。降低柴油机噪音的球铁齿轮研制成功     

奥贝球铁斜楔生产质量控制

本文论述了奥贝球铁斜楔生产的质量控制。奥贝球铁生产铁路货车斜楔满足技术要求σｂ≥１２００ＭＰａδ≥１％αｋ≥３０Ｊ／ｃｍ２（无缺口），零件本体硬度ＨＲＣ３８～４８     

一种高效焊接技术——添加合金粉末埋弧焊

采用普通埋弧焊和添加合金粉末埋弧焊技术,焊接了２０Ｇ和１６ＭｎＲ钢,结果表明,添加合金粉末埋弧自动焊技术能够采用大线能量（因为添加的合金粉末改善了焊缝组织,焊缝深宽比显著提高,而焊缝及ＨＡＺ组织晶粒没有粗化）,焊接工艺性能良好,焊接熔敷速率是传统埋弧焊的２倍,接头角变形明显减小,焊接接头的力学性能满足要求。     

Specific cutting force, tool wear and chip morphology characteristics during dry drilling of austempered ductile iron (ADI)

Dry machining is being recognized as ecological machining due to its less environmental impact and manufacturing cost. However, the choice of dry machining is mainly influenced by the workpiece material properties, machining operation and cutting conditions. The recent emergence of austempered ductile iron (ADI) can be considered a significant economic advantage to the increasing industrial demand for cost- and weight-efficient materials. However, due to its microstructure-induced inherent properties, ADI is considered hard-to-machine material. Thus, the dry drilling of ADI is investigated in this paper. The ADI material used in the present study is produced using an innovative process route for near net shape casting production. Drilling experiments are conducted on a DMU80P Deckel Maho five-axis machining centre using PVD-coated carbide tools under dry cutting environment. The dry drilling of ADI under different cutting conditions is evaluated in terms of specific cutting force and tool wear analysis. The influence of cutting conditions on chip morphology and surface roughness is also investigated. The experimental results revealed that the combination of the low feed rate and higher cutting speed leads to the higher mechanical and thermal loads on the tool's cutting edge, resulting in higher specific cutting force values. This behaviour is further supported by the chip morphology analysis, which revealed the formation of segmented chips at higher cutting speed with segment spacing increase with an increase in feed rate. Depending upon the cutting parameters, different modes of tool failures including crater wear, flank wear, chipping, breakage and built-up edge were observed. Surface roughness analysis revealed the influence of tool wear and chip morphology on the machined surface finish.     

合金元素对室温油分级等温淬火贝氏体球铁组织和性能的影响

采用一种新的室温油分级等温淬火工艺获得低合金贝氏体球墨铸铁;研究了硼、铜、锰对贝氏体球墨铸铁组织和性能的影响,并讨论了球墨铸铁的性能滞后现象,即等温淬火后随时问延长硬度增加的现象。结果表明：硼和锰能提高硬度,降低韧性;铜提高韧性。合理加入合金元素有利于提高贝氏体球铁的性能。贝氏体球墨铸铁有性能滞后现象,其实质是溶质类拖曳作用。     

微合金化铸钢热处理工艺的研究

研究了热处理工艺对铁路车辆用微合金化铸钢ZG18MnNbVTiRe的组织和性能的影响。结果表明：合适的热处理工艺不仅可以消除铸造组织缺陷,还能调整、改善铸钢组织,提高材料的力学性能;奥氏体化后冷却转变组织与冷却方式有关,分别得到正火组织和淬火组织;二次正火、双相正火都能细化组织,得到较好的综合力学性能;经过调质处理能使综合力学性能最好。     

Influence of the processing route on microstructure and mechanical properties of the polycrystalline NiAl

The influence of grain refinement on the mechanical properties of differently processed NiAl was presented. Five NiAl near‐stoichiometric alloys were investigated, three conventionally cast and two sintered from powders (fine‐grained powder made by mechanical alloying and nanopowder made by gas condensation). The mechanically alloyed and cast materials were hot extruded at different conditions to obtain diverse grain sizes. The nanomaterial was synthesized in inert gas condensation and then compacted at 1.4 GPa at 300 °C. It was shown that the ductility and strength can be directly controlled by appropriate texture and grain refinement.     

Transition temperature and fracture mode of as‐castand austempered ductile iron

The ductile to brittle transition temperature is a very important criterion that is used for selection of materials in some applications, especially in low‐temperature conditions. For that reason, in this paper transition temperature of as‐cast and austempered copper and copper–nickel alloyed ductile iron (DI) in the temperature interval from ?196 to +150°C have been investigated. The microstructures of DIs and ADIs were examined by light microscope, whereas the fractured surfaces were observed by scanning electron microscope. The ADI materials have higher impact energies compared with DIs in an as?cast condition. In addition, the transition curves for ADIs are shifted towards lower temperatures. The fracture mode of Dls is influenced by a dominantly pearlitic matrix, exhibiting mostly brittle fracture through all temperatures of testing. By contrast, with decrease of temperature, the fracture mode for ADI materials changes gradually from fully ductile to fully brittle.     

纳米TiN改性TiC基金属陶瓷刀具切削性能的研究

制备了纳米TiN改性的TiC基金属陶瓷刀片 ,并用该刀片与普通TiC基金属陶瓷刀片进行了对比切削试验。结果表明 ,添加TiN纳米粒子可有效改善TiC基金属陶瓷刀具的机械性能和切削性能 ,改性金属陶瓷刀片可以较高切削速度加工碳钢和合金钢 ,此时其主要失效形式为粘结磨损     

Drilling performance of green austempered ductile iron (ADI) grade produced by novel manufacturing technology

Machinability study on drilling of green austempered ductile iron (ADI) grade was conducted using a TiAlN-coated tungsten carbide drill. The green ADI grade was produced by a novel manufacturing technology known as continuous casting-heat treatment technology to save energy and time in foundry. However, in spite of good combination of strength, toughness and enhanced wear resistance, the microstructural properties of ADI sometimes lead to machinability issues. The effect of cutting parameters on cutting force coefficients, chip morphology, and surface integrity of the drilled surface were discussed. Results showed that the strength properties of novel ADI are comparable to that of ASTM grade?1 ADI, whereas percent elongation is comparable to that of ASTM grade?2 ADI. Results obtained also showed that the combined effect of cutting speed at its higher values and feed rate at its lower values can result in increasing cutting force coefficients and specific cutting energy. At higher cutting speed, hardness values increases at the subsurface layer of the drilled surface due to plastic deformation.     

Improving the performance of high-strength steel castings by specialized cooling

The influence of microcooling and external cooling on the structure and mechanical properties of moderately alloyed high-strength special-purpose steel and also on the morphology of its nonmetallic inclusions is investigated. The properties of castings obtained in different molds and in different conditions are compared. The influence of hybrid (external and internal) modification of the casting process on the quality of heavy housing castings is investigated.     

Effect of lubrication and green-compact shape on mechanical properties of mechanically alloyed Zn-22wt%Al powders during hot extrusion of spur gears

We investigated the extrusion behavior of mechanically alloyed Zn-22wt%Al powders with different lubricants and green-compact shapes. The mechanical alloying of powder particles was performed by planetary ball milling for 4 h, 8 h, 16 h, 32 h, and 64 h. The mechanical properties of these powders, as compacted and sintered cylindrical preforms, were estimated by uniaxial compression tests. The alloyed powder with an average particle size of 10 μm obtained after milling for 32 h had the highest compressive strength (288 MPa). Extrusions of miniature spur gears with pitch circles of 1.8 mm using the alloyed powder were carried out at different extrusion temperatures. An extrusion temperature of 310°C resulted in the highest Vickers hardness without surface defects when alloyed powder milled for 32 h was used. To investigate the effect of green-compact shape and lubricant on the dimensional accuracy and cracking regions during the first stage of hot extrusion, extrusion experiments with conical- or cylinder-type green compact shapes and BN spray or a graphite lubricant were performed at an extrusion temperature of 310°C. The results showed that the extrusion of spur gears by using the conical-shaped billet and graphite lubricant resulted in a low extrusion load, good surface roughness, a short cracking region during the first stage, and high dimensional accuracy.