深冷处理对高铬白口铸铁组织与性能的影响

将空淬过的高铬白口铸铁经-196℃深冷处理后在不同温度下回火，研究了深冷处理对该铸铁硬度、冲击韧度、滑动磨损、滚筒式磨损和金相组织等的影响。结果表明：经深冷处理后，其硬度有较大幅度提高，但冲击韧度略有下降；深冷处理后再经250℃回火，可以获得较好的硬度和韧性的配合；经深冷处理后再回火的硬度峰值比未经深冷处理的提前了约100℃；深冷处理对耐磨性影响不明显。     

深冷处理在高铬铸铁中的应用

本试验中将深冷处理工艺引入高铬铸铁的性能研究,初步探讨了深冷处理对材料宏观力学性能及耐磨性的影响。试验结果表明适当的深冷处理能够提高高铬铸铁硬度、冲击疲劳性能及滑动磨损与滚筒磨损性能,但其作用效果有限。     

深冷处理对钛合金力学性能及摩擦磨损性能的影响

为了探究深冷处理对TC4钛合显微组织,力学性能及摩擦磨损性能的影响,采用显微硬度计测定钛合金的表面硬度,光学显微镜观测钛合金经深冷处理后微观组织的变化,万能拉伸试验台测定其拉伸性能,利用摩擦磨损仪研究了深冷处理前后钛合金的磨损性能及利用SEM、EDS分析磨痕的微观形貌和化学成分.结果 表明:深冷处理可以提高TC4钛合金的显微硬度,深冷处理时间为11h时其显微硬度可以达到最大值361 HV1,比初始时提高了3.7％.经过深冷处理后不规则的晶体边角破碎,晶体内的组织均匀化提高;深冷处理可以显著提高材料的抗拉强度,屈服极限及弹性模量,提高材料的力学性能;深冷处理后摩擦系数增加,磨损加剧.     

Ekonol/石墨/MoS2填料对PTFE力学和摩擦磨损性能的影响

研究了Ekonol含量对Ekonol／石墨／MoS2／P，PTFE复合材料的力学性能、摩擦磨损性能的影响，以及滑动速度、载荷对材料摩擦磨损性能的影响；用扫描电子显微镜观察了复合材料磨损后的表面形貌，并探讨了其磨损机制。结果表明：加入填料降低了材料的拉伸强度和弯曲强度，但提高了弯曲模量和硬度；同时填料能提高材料的磨损性能，但使摩擦因数升高了；当Ekonol含量较低时，磨损机制为粘着磨损，随着填料含量的增加，Ekonol分散到基体中，起到了承载作用，阻止了PTFE基体的带状破坏，磨损机制为疲劳磨损和轻微的粘着磨损；摩擦因数随载荷的增大而减小，随滑动速度的增大而增大，在相同的滑动时间内，磨痕宽度随载荷和滑动速度的增大而增大。     

深冷处理对GCr15轴承钢组织及力学性能的影响

对GCr15轴承钢分别进行淬火+回火,淬火+回火+深冷,淬火+深冷+淬火,淬火+回火+深冷+回火处理,研究了深冷处理对GCr15轴承钢显微组织、硬度和耐磨性能的影响。结果表明:与常规淬火+回火工艺相比,增加深冷处理工序后试样中残余奥氏体含量明显降低,硬度增大,耐磨性提高;淬火+深冷+回火处理试样的残余奥氏体含量最低,硬度最高,耐磨性最好,其磨损量比淬火+回火处理试样的减少了6%;深冷处理提高了GCr15轴承钢的抗疲劳磨损和磨粒磨损的能力。     

深冷处理对PCBN刀具切削性能的影响研究

针对PCBN刀具在硬切削加工中磨损严重、切削寿命短的问题,开展了PCBN刀具深冷处理试验和经深冷处理的PCBN刀具高速硬车削AISI 4340钢的试验,研究深冷处理对PCBN刀具表面完整性（包括微观形貌、粗糙度、显微硬度和残余应力）及切削性能的影响规律,探究提高PCBN刀具耐磨性和刀具寿命的方法。研究结果表明,经过深冷处理之后,刀具表面缩松缩孔等缺陷明显减少甚至消失,表面形貌得到改善,但刀具表面粗糙度增大;刀具表面显微硬度、残余应力均得到提高;表面形貌和表面残余应力对刀具寿命影响较大,其次是表面显微硬度,表面粗糙度对刀具寿命影响较小。深冷处理后,刀具黏结、氧化磨损减少,刀具寿命较未处理刀具提高24.78%,可见,深冷处理可有效改善PCBN刀具表面完整性,从而提高刀具寿命。     

表面处理对TiAlSiN涂层刀具表面完整性及切削性能的影响研究

涂层刀具在高速干切削钛合金时容易出现刀具磨损严重、刀具寿命短等问题,对涂层刀具进行表面处理能改善涂层刀具的表面完整性,是提高涂层刀具耐磨性和切削寿命的有效途径。选取TiAlSiN涂层刀具,分别进行深冷处理、微喷砂处理和深冷+微喷砂处理,研究不同处理方法对涂层刀具表面完整性(包括表面形貌、表面粗糙度、显微硬度和表面残余应力等)的影响,并进行钛合金高速干切削试验,分析不同处理方法对涂层刀具切削性能的影响,探究提高涂层刀具耐磨性和切削寿命的方法。结果表明：与单一深冷处理和微喷砂处理相比,深冷+微喷砂处理后涂层刀具表面完整性明显改善,刀具寿命显著提高。深冷+微喷砂处理能减少刀具崩刃、月牙洼磨损和磨粒磨损,有效提高涂层刀具耐磨性。     

深冷处理对W9Mo3Cr4V刀具耐磨性能影响的研究

采用微机控制的刀具深冷处理装置对W9Mo3Cr4V高速钢成品刀具进行深冷处理研究。对深冷处理后的刀具和未经深冷处理的刀具在硬度、耐用度及金相显微结构方面进行了实验对比。结果表明，深冷处理可以改变高速钢刀具材料的微观组织结构，并在一定程度上提高刀具材料的硬度，增强刀具材料的耐磨损性能。分析了产生这种变化的机理。     

深冷高速钢丝锥在攻钛合金时刀具的磨损机理及耐用度

分析深冷处理后的EM35高速钢丝锥在攻钛合金时的磨损型式、破损形态,通过采用不同的攻丝速度攻丝,研究丝锥后刀面的磨损规律和使用寿命,并绘制了v-T曲线图进而推算出深冷处理后,EM35高速钢丝锥在攻钛合金时的经验公式。发现:攻钛合金时粘结磨损为主要失效形式,氧化磨损和磨粒磨损很小。丝锥经深冷处理后主要磨损机理并没有发生改变,但可以细化晶粒,提高刀具表面硬度,增强表面抗磨性能。与未深冷丝锥相比可提高使用寿命87.5%。     

等离子表面钼铬共渗制备强化层的研究

利用辉光离子渗金属技术在Q235钢表面进行钼铬共渗，随后进行渗碳淬火、深冷处理及回火复合处理，对渗层组织、成分、硬度和摩擦磨损性能进行了分析。结果表明：渗层化学成分接近钼系高速钢；渗层中的碳化物细小、均匀、弥散，没有粗大的共晶莱氏体组织；经深冷2h处理试样表面硬度达到1600HV，明显高于未经深冷处理试样的表面硬度；经不同时间深冷处理试样的滑动摩擦因数基本相同，但比未经深冷处理的试样降低约15％，其相对耐磨性分另q是未渗金属试样的2．10倍和3．59倍。     

Effect of cryogenic treatment on the matrix structure and abrasion resistance of white cast iron subjected to destabilization treatment

Effect of deep cryogenic treatment on the matrix structure and abrasion resistance of high chromium cast iron subjected to destabilization heat treatment has been investigated in this paper. The results show that, during the cryogenic treatment, the secondary carbides precipitate in austenite, which promote the transformation of retained austenite to martensite. The cryogenic treated alloys produced superior hardness and wear resistance (β) to the alloys without cryogenic treatment. When the bulk hardness and wear resistance (β) reach the maximum, there is still about 13% retained austenite in alloys. Cryogenic treatment cannot make retained austenite transform to martensite completely.     

7A04铝合金深冷处理的组织和性能研究

对7A04铝合金试样分别采取普通固溶处理和固溶加深冷处理,并在不同的温度下进行人工时效。结合金相组织,硬度、抗拉强度和冲击韧性的测试值对比两组工艺,分析深冷处理对7A04铝合金时效金相组织和力学性能的影响。结果表明:深冷处理能使7A04铝合金在晶粒内外产生大量析出相,并形成较为均匀的弥散分布。7A04铝合金固溶+深冷处理的理想时效温度为120℃,时效16 h,峰值时效硬度为190 HB,最高抗拉强度为679 MPa,与普通固溶处理相比分别提高了24.1%和26.9%,韧性略有提高,具有较高强韧性。     

改善Crl2MoV钢综合力学性能的工艺分析

对Crl2MoV钢在淬火后采用深冷处理和中低温回火相结合处理工艺,通过显微组织及硬度、冲击功和抗弯强度等力学性能测试,研究了深冷处理对Crl2MoV钢组织和性能的影响,结果表明：1020℃30nlin油淬＋200℃回火1h＋深冷处理＋400℃回火2h工艺处理,具有较好的综合力学性能。     

Reply to comments on “Transition from ploughing to cutting during machining with blunt tools”

The low-stress and gouging wear behavior of a series of Ni-Cr white iron (Ni-Hard 4) samples has been characterized. The samples were processed to contain 5–85% retained austenite in their microstructures so that their Rockwell C hardness ranged from 63 to 47. The low-stress abrasion behavior was measured with loose SiO₂ and Al₂O₃ abrasives in a rubber wheel test system. The gouging abrasion behavior was determined in a bonded Al₂O₃ wheel test system. Wear scars were characterized by scanning electron microscopy used in conjunction with energy dispersive X-ray spectroscopy.Both low-stress and gouging wear behavior were strong functions of test condition and microstructure, and weight losses passed through maxima or minima as the volume fraction retained austenite or abrasion condition varied. Carbides controlled wear behavior in the low-stress test against SiO₂, and their attrition occurred by uniform scratching, preferential chipping at leading edges and cracking-spalling. In low-stress and gouging tests against Al₂O₃ carbides and matrix underwent attrition by uniform micromachining. The test results indicated that retained austenite content could be used to optimize wear resistance in a variety of abrasion situations.     

The effects of cryogenic treatment on the toughness and tribological behaviors of eutectoid steel

Cryogenic treatment is a supplementary heat treatment usually applied after quenching. Its effects are permanent and this process affects the entire section. There have been many studies related to cryogenic treatment, most of which have been focused on tool steels. In the current study, a high-speed-train railway material was investigated, and different heat treatment processes were applied to the eutectoid steel. The effects of quenching and cryogenic treatment were investigated on the mechanical properties (toughness, hardness and wear). Four different structures were obtained with different heat treatment cycles: Pearlitic, tempered martensite, 12 hour cryo-treated tempered and 36 hour cryo-treated tempered. As a result of Charpy v-notch tests and hardness tests, cryogenic treatment was found to improve the toughness and hardness of quenched samples. The results of the ball-on-disc wear tests showed that the cryo-treated samples have better wear resistance than pearlitic and martensitic samples.     

Correlations between two-body and three-body abrasion and erosion of metals

The effects of various variables on the wear resistance of different pure metals are compared for two-body abrasion, three-body abrasion and erosion. The variables studied are the annealed hardness of the worn metal, the increase in hardness of the worn metal before the wear process due to work hardening and heat treatment, the applied load, the distance travelled, the abrasive particle size and the abrasive hardness. It was found that the effects of most of these variables are similar for the three different wear processes.     

Hysteresis in the abrasive wear of brittle solids

Observations of microfracturing around scratches have established that the microfracturing is similar to that which occurs beneath a quasi-static pointed indentation but only for a constant load. Increasing and decreasing the load cycle revealed residual stress depending on the scratching velocity and the environment. The three-dimensional analysis is appropriate because lateral cracks occur ahead of the scratching point. The traditional concept of volumetric loss of material for two-body abrasion based only on a material property such as the hardness or the stress intensity factor seems to be insufficient and the “history” of deformation needs to be considered.     

Metallurgical and mechanical characteristics of cryogenically treated tungsten carbide (WC–Co)

This paper aims to present the metallurgical and mechanical characterization of cryogenically treated tungsten carbide (WC–Co) in terms of α-, β-, γ-, and η-phase particles and wear behavior, respectively. The specimens of commercially available uncoated WC–Co in the form of round turning inserts were procured and subjected to cryogenic treatment at two levels ?110°C (shallow treatment) and ?196°C (deep treatment) of temperature. The microstructures obtained after cryogenic treatments have been characterized with a prominence to comprehend the influence of cryogenic treatment on the nature, size, and distribution of α-, β-, γ-, and η-phase particles as compared to untreated specimen. The mechanical properties such as hardness and wear rate of the specimens have also been compared by performing Rockwell A hardness test and pin-on-disk wear test, respectively. Microstructures, hardness, wear rate, and analysis of worn surface divulge the underlying metallurgical mechanism responsible in improving mechanical properties of the WC–Co.     

45钢代替硬质合金制作冷拔拉模

讨论了硬质合金镶套冷拔拉模的优势和缺陷 ,分析了采用Cr12MoV钢固体渗硼工艺和采用 45钢复合热处理工艺制作冷拔拉模的工艺路线并对二者进行了比较。试验结果证明 ,用加工性能好、价格低廉的 45钢经复合热处理后制作的冷拔拉模其内孔具有很高的硬度和耐磨性 ,完全可以代替硬质合金冷拔模具     

Optimization of Deep Cryogenic Treatment Process for 100Cr6 Bearing Steel Using the Grey-Taguchi Method

This article presents a method for optimizing the deep cryogenic treatment (DCT) process parameters for 100Cr6 bearing steel, based on the Taguchi method with Grey relational analysis. The DCT parameters considered for the optimization included the cooling rate, soaking temperature, soaking time, and tempering temperature, with the quality targets of dimensional stability, wear resistance, and hardness. As per the Grey-Taguchi technique, nine experimental trials based on the L₉ (3⁴) orthogonal array were conducted. The optimum parameters for 100Cr6 bearing steel were arrived at based on Grey relational analysis. Analysis of variance (ANOVA) was performed and soaking temperature was identified as the most influential factor in deep cryogenic treatment of 100Cr6 bearing steel. The improvement in dimensional stability, wear resistance, and hardness of the deep cryotreated samples under optimized treatment conditions was 13.77, 49.02, and 19.35%, respectively. A microstructural examination was carried out to identify the possible mechanism of cryogenic treatment in improving the properties of the 100Cr6 bearing steel. A confirmation test was subsequently conducted to validate the test results.