W6Mo5Cr4V2高速钢圆刀片的热处理

研究了W6Mo5Cr4V2高速钢圆刀片热处理后的组织，性能，与Cr12MoV刀片进行比较，寿命617－1000t/一次修磨，比日本进口刀片寿命略有提高。     

梯度结构硬质合金涂层刀片切削性能研究

研究了梯度结构硬质合金涂层刀片和无梯度结构硬质合金涂层刀片的切削性能．并对不同钴含量梯度结构硬质合金刀片的切削性能进行了对比实验。实验表明：具有梯度结构硬质合金涂层刀片的切削性能比无梯度结构硬质合金涂层刀片的切削性能优良；达到同一磨损高度hB=0．15mm时，前者的切削寿命较后者提高了近一倍；同时随着合金钴含量增多，硬质合金刀片的切削性能提高。     

可转位刀片合理价格的计算

金属加工工业的发展要求采用高效率加工方法,提高工具寿命及切削速度,因此,当前改进硬质合金金属切削工具的主要方向之一是高效率的可转位刀片的推广应用。可转位刀片的应用可以省去刀片焊接及刀刃重磨等工序,消除工具制造过程中出现的裂纹及显微裂纹,从而大大地提高了切削工具的使用性能。缩短了工具的调整时间,降低了生产费用。装配国产可转位刀片的刀具在苏联的维     

双刀片切削技术在轧辊加工中的应用研究

传统的单刀片刀具加工,受限于刀具强度、寿命等因素,机床功率只能发挥20%～50%,机床功率不能得到充分利用。通过双刀片刀具的应用,可达到双刀架的效果,提高了设备利用率,提高了加工效率。双刀片刀具通过双刀片同时切削,同等情况下,明显的提高了切削深度,有效提高了机床功率利用率,加工效率提高70%～90%。在机床功率允许的情况下,还可以应用于双刀架机床,实现四个刀片同时切削,可进一步提升双刀架机床的加工效率。对于加工余量较大的粗加工,双刀片刀具效果更明显。     

Co含量对硬质合金梯度结构和性能的影响

采用分段烧结的试验工艺,通过改变原料中钴的含量来研究钴含量对硬质合金梯度结构和性能的影响。试验主要从钴含量对梯度烧结后、涂层后合金的机械性能、梯度结构的变化情况进行了探索,并研究了梯度硬质合金刀片的切削性能。试验表明,随着合金钴含量增多,合金梯度结构越明显,梯度层厚度增加;合金的强度与磁饱和提高,硬度、磁力和密度减小。同时随着合金钴含量增多,经涂层处理的硬质合金刀片的切削性能提高,达到同一磨损高度VB=0.12mm时,FGCC-Co-8刀片的切削寿命较FGCC-Co-6刀片提高了三分之一。     

机夹刀片

株洲硬质合金厂在生产斗争和科学实验中不断地总结经验,74年以来开始大批生产机夹刀片,75年产量已突破50吨大关,43个品种,24个规格。76年要在75年基础上实现翻番,突破100吨大关。与焊接刀片相比,机夹刀片有如下一些优点: 1.刀具不需焊接刃磨,完全避免了产生内应力和裂纹的可能性,因而刀具的寿命平均提高1～1.5倍。     

收割机刀片使用寿命创最好指标

在毛主席“农业的根本出路在于机械化”的光辉教导指引下,北京钢铁研究院于1974年底接受了一机部委托的“关于提高收割机刀片使用寿命”的研究课题。1975年初即开展了这方面的工作。收割机刀片是易磨损、用量大的关键部件,原用T,高频感应淬火的刀片磨损快、寿命低,影响收割速度,误农时,远远满足不了农业大发展的需要。科技人员本着急广大贫下中农之所急,在课题一开展就坚持科研、生产、使用三结合,为贫下中农服务,在确定研究方案时尽力考虑到研究出来的刀片既经济、又耐用,为广大贫下中农所欢迎。首先将原来的刀片材料T_9冷轧带改为45号碳素结构钢冷轧带,并采用工艺简便、原料来源方便又便宜的液体渗硼工艺,进行定刀刃边渗硼处理,使刃口获     

硬质合金基体对涂层刀具高速切削镍基高温合金切削性能的影响

采用热常数仪和高温维氏硬度计对Co含量(质量分数)分别为6%和10%的硬质合金进行热学性能与高温力学性能检测,然后用以这2种硬质合金为基体的涂层刀片对镍基高温合金GH4133进行高速车削,采用扫描电镜(SEM)和能谱(EDS)对车削后刀片的磨损区域进行观察和成分分析,研究刀片基体的Co含量对刀具切削性能的影响。研究结果表明,硬质合金中的Co含量由10%降低到6%时,热导率由62.78(W.m)/K升高到84.57(W.m)/K,与此同时同一温度下的高温维氏硬度提高10%左右;YBG202刀片(基体中Co含量为10%)的切削刃与后刀面的磨损均较迅速,而YBG102(基体中的Co含量为6%)刀片后刀面的磨损相对均匀,磨损速率低;基体中的Co含量由10%降低到6%时,刀片的切削寿命提高约3倍。故高速连续切削镍基高温合金时应当尽量选用低Co硬质合金作为刀片的基体。     

45钢收割机刀片的渗硼工艺及渗硼层性能的研究

收割机刀片是用量大的易损件,主要问题是不耐磨、寿命低。自将原用的T9A钢高频感应加热淬火工艺改用45钢渗硼处理后,有效地提高了刀片刃口的硬度和耐磨性,使用寿命成倍地提高。为了完善工艺,解决生产中出现的问题,本文对盐浴渗硼工艺进行了研究,着重解决了大批量小零件产品渗硼后硼盐清洗、热处理和贮存过程中锈蚀的关键技术问题。同时采用金相,X光衍射,俄歇能谱等方法对渗硼层的组织结构及腐蚀性能进行了探讨。     

铣削高锰钢用高性能硬质合金铣刀材料的研制

通过对硬质合金的材料成分、碳化物晶粒度、复杂碳化物相间的交互作用分析,并辅以合适匹配的刀具参数进行分析和研究,优选出固溶体、黏结相和晶粒度合理配比,研制出了新型硬质合金D16刀片材料。结果表明以该材料制成的硬质合金铣刀性能良好,完全可以替代德国维迪亚TN35M铣刀,经试验,其寿命超过进口铣刀一倍,超过国内同类刀片材料(自贡767,YC30S)寿命4~6倍,是一种比较理想的铣削高锰钢用高性能硬质合金铣刀材料。     

双卧轴强制式混凝土搅拌机叶片的磨料磨损研究

双卧轴强制式混凝土搅拌机是一种高效、快速的混凝土搅拌器械,广泛用于各种混凝土工程中。以某型号双卧轴强制式混凝土搅拌机为研究对象,根据磨料磨损机理推出搅拌叶片线磨损率的计算公式,通过Fluent软件的计算和相关后处理工作得出搅拌叶片表面线磨损率的分布。分析结果表明,搅拌叶片的顶端附近处线磨损率最大,磨损最为严重;根据线磨损率的数值可预估搅拌叶片的使用寿命。研究对于预估整机的使用寿命提供了一定的理论依据和数值依据,对搅拌臂的布局和搅拌叶片材料的选择和处理也提供了一定的科学依据。     

Service failure of hot-stage turbine blades:

Surface-connected porosity in current military aircraft hot-stage turbine engine blades is associated with blade failure. Oxidation ratcheting is suggested as the failure mechanism. Sta- tistical comparison of new and used blade populations showed that for blades cast with an equiaxed structure, the porosity in new blades was associated with crack formation on the con- cave surface of the used blades. The pores did not tend to develop into cracks on the compressed (convex) surface of the blade. Insufficient suitable data on directionally solidified blades pre- vented similar statistical correlations. However, metallography of the directionally solidified blades showed that the in-service cracks were related to oxidation inside surface-connected pores and that the cracks were oriented in the same direction as the (axial) casting pores. Thus, the proposed failure mechanism through ratcheting is based on the following insights: (1) the blades are thermally cycled as a normal part of service; (2) the hot blades expand and the open pores are filled with oxide; (3) when the blade is cooled, thermal contraction of the metal is greater than the oxide, causing compressive stress and yield; and (4) thermal expansion of the blades opens the pores again, since yield relaxed compressive stress at low temperature. These insights were supported by metallographic and computer-simulation studies which showed that the pores grow 20 to 50 pct in width per 100 missions (about 90 hours of operation) for a military aircraft on a typical mission profile.     

4Cr2WMoVSi热作模具钢的研究与应用

以多元少量的合金化原则设计的4Cr2WMoVSi钢是一种经济型热作模具钢,研究了4Cr2WMoVSi钢的热处理工艺及性能,并与3Cr2W8V钢的热处理工艺和性能作了对比,用4Cr2WMoVSi钢制作了热剪刃,进行了装机使用试验,其使用寿命与3Cr2WSV剪刃的寿命相当,而是5CrW2Si剪刃寿命的3．4倍。     

Microstructure,creep properties,and rejuvenation of service-exposed alloy 713C turbine blades

A study was carried out on the microstructure and creep properties of aero engine first-stage turbine blades made from Alloy 713C nickel-base superalloy. Results are reported for new blades, blades in two service-exposed conditions, and service-exposed blades subjected to one of three rejuvenation treatments: a recoating heat treatment, a hot isostatic pressing (HIP) + recoating heat treatment, and a HIP + controlled cooling + recoating heat treatment. The blade microstructure undergoes significant change during service, and this leads to a loss in creep properties exhibited by specimens machined from the blade airfoils. Good correlations were observed between the rupture time and the amount of blade airfoil untwist and between the minimum creep rate and the amount of untwist. The recoating heat treatment and the HIP + controlled cooling + recoating treatment were moderately successful in restoring the microstructure and creep properties of the service-exposed blades. In comparison, the HIP + recoating treatment was very successful in rejuvenating creep properties but only for blades having a chemical composition with a lower propensity to form σ phase. For the blades with an unfavorable composition, σ phase was found to form preferentially near the grain boundaries during creep testing, and this had a detrimental effect on the creep properties. Nonetheless, the degree of rejuvenation for these blades was always at least as good as that obtained through the recoating heat treatment alone. Formerly National Aeronautical Establishment     

秦岭发电厂应用粉末喷焊技术获得显著技术经济效益

秦岭发电厂对本厂使用的12.5万千瓦和20万千瓦发电机组的排粉机叶片、引风机包头及防磨板、除尘器喷嘴喉部喷水管等部件进行了粉末喷焊。不仅延长了零部件的使用寿命、减少更换次数、保证安全发电和供电,而且一年之内节约直接资金达到338258元。应用该技术获得了显著的技术经济效益。     

金刚石有序排列对锯片性能的影响

排布方式合理的有序排列金刚石锯片能明显提高锋利性,增加寿命。试验采用2片无序排列锯片和4片有序排列锯片切割混凝土,不同排布方式的锯片切割性能有很大的差异。介绍了有序排列锯片制作的工艺流程,并且从理论上分析了排布参数对切割性能的影响,提出横向间距和纵向间距是有序排列方式设计中最重要的两个参数。     

激冷与锑复合变质在大型矿山风机铝合金叶片上的应用

文中介绍风机叶片由原来采用钢板冲压成形、焊接而成，改为铝合金并应用激冷与微量元素锑复合变质后，不仅使叶片的内、外质量得到了保证，还大大提高了铸件的耐蚀性和使用寿命，降低了动力消耗和成本。     

Bifilm Defects in Ni-Based Alloy Castings

The Ni-base superalloys, which are normally melted and cast in a vacuum, entrain their surface-oxide film during turbulent pouring of the melt; unfortunately at this time, this process is universally practiced for investment castings of these materials. The entrained film becomes a bifilm crack automatically, so that cast alloys have a large population of cracks that controls their failure behavior. The problems of the growth of single crystals and the welding of polycrystalline alloys are reviewed to illustrate the central role of bifilms in the cracking of turbine blades, the heat-affected zones of welds, and the reliability of properties. It has been demonstrated that improved gravity pouring systems can reduce these problems significantly, but only countergravity filling of molds is expected to result in defect-free castings. Recent cases in which turbine blades failed in service are examined, and the central role of bifilm defects in these failures is discussed.     

Analysis of the causes of fracture of turbine blades in a gas-compressor unit

The problems of the fatigue life of gas-compressor unit blades are discussed. In particular, the results of fractographic investigation are used to formulate the specific features of fracture of stamped lowpressure turbine blades made of an EI893 alloy, which exhibit the maximum number of damages in a five-year period. In 80% cases, fracture begins with the formation of a brittle zone in the leading edge of a blade airfoil because of the resonance phenomena caused by a break in the stiffness of the blade–turbine disk joint. This conclusion is supported by pronounced traces of fretting corrosion in the contact surfaces of the joint of a failed blade and a disk.     

盘区下向充填分层道稳定性数值模拟

龙首矿采用下向水平分层六角形进路充填采矿法,分层道是关键通道,其稳定性至关重要。应用FLAC3D软件建立了分层道及六角形进路数值模型,应用强度等效原则确定了分层道底部配筋充填体的力学参数。分别研究了分层道假顶为素充填体和配筋充填体情况下的稳定性。结果表明,分层道开挖暴露的大面积矩形薄板,最大挠曲在中部位置,破坏方式从中部开始拉断破坏,应在开采过程中加强对顶板的支护及对中部位置的监测。此外,分层道假顶为素充填体时不利于矿山的安全生产,尤其在进路与分层道交叉巷道处,应加密配筋密度,防止出现冒落及掉块现象。