两种新型粉末冶金(PM)立铣刀的使用

<正>无论在实验室或在生产现场都证明,PM(粉末冶金)高速钢立铣刀比普通高速立铣刀具有更好的切削性能和较长的使用寿命.下面介绍由国外公司最新推出的两种PM高速钢立铣刀的切削试验情况.(1)日本日立工具公司推出的 ESM PM高速钢立铣刀具有硬度高(HRC70)、韧性好(比硬质合金还好)的特点,采用两槽小φ8mm的ESMPM高速钢立铣刀和同样尺寸的高钴高速钢立铣刀在H-13工具钢试件上铣削 2.5×1.2mm的槽作切削对比试验,试验中选择不同的切削速度和进给量(见图).结果表明,ESM PM高速钢立铣刀的切除量是普通高速钢立铣刀的2倍,切削中同时还选用了细晶粒硬质合金立铣     

微径钻铣刀具的失效形式及抑制措施分析

由于具有刃口半径效应、径向刚度差、旋转速度高、切削稳定性差等特性,微径钻、铣刀具具有不同于常规尺度钻、铣刀具的失效特征。基于大量钻削和立铣削试验,在对常规尺度麻花钻、平头立铣刀的一般失效形式简要分析的基础上,研究了微径麻花钻和平头立铣刀的特殊失效形式及原因,提出了抑制微径钻、铣刀具失效的基本方法。结果表明:容屑空间堵塞、塑性变形、断齿是微径钻、铣刀具常见的失效形式;随着刀具直径减小、转速增高,整体断裂成为微径钻、铣刀具的最主要失效形式;改善材料切削性能、提高切削液作用效果、优选刀具材料及结构、优化切削工艺是抑制微径钻、铣刀具失效的根本措施。     

日本工具制作所的新型立铣刀

<正> 在第13届日本国际机床展览会上,日本工具制作所展出了该公司开发的三种立铣刀新产品。 1.ESM立铣刀此种立铣刀采用该公司新开发的高级合金粉末高速钢制作,既具有一般高速钢的韧性,又具有硬质合金的耐磨性。 ESM立铣刀的特点: ①与该公司以往的立铣刀相比,切削速度和进给量提高2倍,使用寿命提高5倍,可用于高速大进给     

活化处理对高速钢Ni-W-P化学镀层结合力影响

为提高Ni-W-P化学镀层与高速钢基体之间的结合力，重点研究了高速钢化学镀前的表面活化处理工艺。以不同浓度的盐酸、硫酸、氢氟酸和活化时间为研究对象，以Ni-W-P镀层与高速钢基体的结合力为研究指标，通过正交试验对活化剂组分和活化时间进行优化。结果表明，在试验条件下，当活化剂中添加8%的浓盐酸和2.5%的氢氟酸(其余为水)并对高速钢基体进行3 min活化处理时，制备的Ni-W-P镀层与基体的结合力最大。     

多层电磁屏蔽镀层制备工艺研究

研究在工程塑料上,采用化学镀的方法,先镀Ni-P-Cu镀层,再镀Ni-P镀层,使其在较宽频段范围内,具有优异的电磁屏蔽性能,同时又具有化学镀层优良的抗氧化性能和耐腐蚀、耐磨性能.     

高合金粉末高速钢立铣刀

高合金粉末高速钢立铣刀日立工具公司采用高合金粉末高速钢作为基体材料，开发出一种粗加工用的立铣刀，并经特殊涂层处理。这种立铣刀是在该公司原有产品ＥＳＭ立铣刀基础上，加以改进后的产品。两者所用的基体材料一样，ＥＳＭ立铣刀未涂层，新产品则经涂层处理，其工具...     

高效率立铣刀

高效率立铣刀日立工具公司最近开发出一种高合金粉末高速钢（ＥＳＭ）立铣刀，并经过复合涂层（代号为Ｃ涂层）处理．与普通齿形的高速钢立铣刀相比，新型产品的芯厚增大，螺旋角也较大，排屑性能良好，用一把立铣刀即可进进行沟槽、侧壁、型腔等的加工。新型立铣刀的切削...     

波形刃立铣刀的特点及其用法

近来由于致力于省力化、高速化,数控机床等机械的飞跃发展,因之也就相应地要求有耐重切削的高速钢刀具。铣刀当中高速钢立铣刀的需要量大。普通立铣刀随着每一切削刃的切削用量的增     

501高速钢的磨削

<正> 重庆钢铁厂生产的501高速钢(W_6M_5Cr_4V_2Al),近年来在我厂生产的刃具中应用越来越广泛。这种高速钢比普通高速钢(W_(18)Cr_4V)具有更好的切削性能和较高的耐用度,而价格与普通高速钢相近。去年12月我厂为美囪试制的立铣刀,由501钢整体制造。经美方试验:用美方生产的立铣刀(W_(18)Cr_4V)加工某产品需耗费10把刀8个小时,而用我厂生产的立铣刀加工同一产品,只耗费2把刀3个小时,工效与刀具寿命都大大提高。但由于这种材料经     

整体硬质合金立铣刀

从80年代初开始,在国外整体硬质合金立铣刀取得了飞跃发展,有取代以高速钢为主的立铣刀的发展趋势。整体硬质合金立铣刀多用于精加工,也是实现高效、低成本的加工方法,并延长了工具寿命,对难加工材料的加工发挥着优异性能。国内随着NC铣床和加工中心的普及,各种精密零件及精密模具等加工需要,开始逐步推广使用整体硬质合金立铣刀。整体硬质合金立铣刀与高速钢立铣刀相比,有易断、易崩刃、价格高等不足之处。其原因多是由于对整体硬质合金立铣刀认识不足,或者使用不当及切削条件不合理等原因而造成的。     

Characterization of DC magnetron sputtered diamond-like carbon (DLC) nano coating

Development in vapor deposition techniques over the last two decades has led to the introduction of many advanced coatings for metal-cutting tools. This paper examines the characteristics of multilayer Ti, TiN, and diamond-like carbon (DLC) coatings deposited on standard tool substrates at varying sputtering parameters and conditions, such as power density, partial pressure, substrate temperature, and reactive gases. The characteristics of films were examined using an X-ray diffractometer, Raman microscope, surface profilometer (to measure the thickness of the coating), Rockwell hardness tester (to test adhesion), and a micro hardness tester. The pin-on-disc test setup was used to find the coefficient of friction of the coatings. The results indicated that a graded multilayer coating showed better adhesion to the substrates. It was observed that higher target power density resulted in an increase of micro hardness and crystalline planes of coating. Lattice constant matching among layers of coating, proper substrate preparation, and a sequence of cleaning processes are the crucial factors for the enhancement of adhesion strength.     

化学沉积镍-钼-磷合金在NaCl溶液中的耐腐蚀性能

通过化学沉积获得不同晶态镍钼磷合金镀层,探讨了不同晶态及钼的添加量对化学沉积镍-钼-磷合金镀层在NaCl溶液中耐腐蚀性能的影响.结果表明:非晶态镀层有着较晶态镀层更好的耐蚀性能;磷含量一定时,钼的添加可较好地提高镀层的耐蚀性能.     

基于工艺控制与基体处理的类金刚石涂层性能优化技术研究综述*

类金刚石涂层(DLC)因其高硬度、高耐磨性、低摩擦因数等特性被广泛用作机械零部件润滑防护涂层,但传统的DLC涂层在高速、重载及高温等苛刻工况下易发生摩擦因数升高、开裂及鼓包/起皮并从基材脱落进而导致涂层润滑防护失效。基于工艺控制及基体处理2个方面,从涂层的沉积工艺、元素掺杂、过渡层的添加及渗氮渗碳、改变粗糙度、加工表面微织构等手段对提升DLC涂层服役性能的优化措施进行综述;针对提高DLC涂层服役性能的措施进行理论分析,并提出未来的研究方向,如建立规范统一的高性能DLC涂层的制备工艺及性能表征方法,进一步探讨不同基体粗糙度对涂层机械啮合力的影响,以及微织构的尺寸效应及对DLC涂层的热应力缓释作用。     

The effects of AlCrN coating,surface modification and their combination on the tribological properties of high speed steel under dry conditions

In this study, the effects of a combination of ultrasonic nanocrystalline surface modification (UNSM) technique and AlCrN coating on the tribological properties of high speed steel (HSS) were investigated. The AlCrN coating with a thickness of about 3 µm was deposited by the physical vapor deposition (PVD) technique onto the polished and UNSM-treated HSS specimens. The tribological and scratch tests results revealed that the AlCrN coating deposited onto the UNSM-treated specimen showed better tribological properties compared to that of the AlCrN coating deposited onto the polished specimen, which may be attributed to the modified surface beneath the AlCrN coating. Hence, it is expected that the results of this study can be applied to reduce the wear of fine blanking punches.     

Wear behavior of Ni–P and Ni–P–Al2O3 electroless coatings

In this research, hardness and wear resistance of two types of electroless coating have been investigated including Ni–P and Ni–P–Al₂O₃ coatings. These coatings were applied on AISI 1045 steel discs by electroless deposition process and then they were heat treated at 200, 400 and 600 °C for 1 h. Wear resistance of deposits was measured by the pin on disc method and wear surfaces and debris were studied by scanning electron microscopy (SEM). Also, microstructural changes were evaluated by X-ray diffraction (XRD) analysis.The results showed that the existence of alumina particles in Ni–P coating matrix led to an increase in the hardness and wear resistance of the deposits. It was also found that heat treated coatings at about 400 °C have the maximum hardness and wear resistance.     

Substrate dependence of the scratch resistance of CrN<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> coatings on steel

Hard CrN_x coatings were sputter deposited on hot work tool steel (HWTS) and high speed steel (HSS) in an industrial PVD reactor. Coatings were deposited under various nitrogen flows. The thickness, density, hardness, elastic modulus, composition, and stress were determined for the coatings. The specimens were subjected to scratch testing. Two different failure mechanisms were investigated: chipping and complete coating removal. For all specimens, the coating-to-substrate adhesion was that good that adhesion did not limit the scratch resistance. Therefore, the minimum loads at which a given type of failure was initiated were not a measure for the coating-to-substrate adhesion. The scratch resistance was better for coatings on HSS than for coatings on HWTS. This is due to the higher hardness of the HSS. Substrate independent measures for the scratch resistance of the coating were obtained by considering critical track widths instead of critical loads. The hardening of the coating--substrate systems due to the coating was investigated. The uncoated substrates exhibited track width independent scratch hardness. For the coated specimens the scratch hardness increased with increasing track width until chipping of the coating occurred. Complete coating removal coincided with a decrease in hardness. Although the elastic properties, hardness, and thickness of all coatings were more or less equal, CrN_1.0 coatings outperformed CrN_0.6 coatings in scratch tests both on HSS and on HWTS.     

Ni-P-Cr2O3化学复合镀层耐磨性的研究

研究了热处理对Ni-P-Cr2O3化学复合镀层组织结构、硬度及耐磨性的影响，并与Ni-P镀层作了对比。结果表明，镀层的摩损规律与硬度变化规律不同，采用正确的热处理工艺，可使镀层的硬度及耐磨性显著改善。     

Synergistic effect between nano-ceramic lubricating additives and electroless deposited Ni-W-P coating

The major solving ways for the material wear are surface modification and lubrication.Currently,the researches at home and abroad are all limited to the single study of either nano-lubricating oil additive or electroless deposited coating.The surface coating has high hardness and high wear resistance,however,the friction reduction performance of the coating with high hardness is not good,the thickness of the coating is limited,and the coating can not regenerate after wearing.The nano-lubricating additives have good tribological performance and self-repair function,but under heavy load,the self-repair rate to the worn surface with the nano-additives is smaller than the wearing rate of the friction pair.To solve the above problems,the Ni-W-P alloy coating and deposition process with excellent anti-wear,and suitable for industrial application were developed,the optimum bath composition and process can be obtained by studying the influence of the bath composition,temperature and PH value to the deposition rate and the plating solution stability.The tribological properties as well as anti-wear and friction reduction mechanism of wear self-repair nano-ceramic lubricating additives are also studied.The ring-block abrasion testing machine and energy dispersive spectrometer are used to explore the internal relation between the coating and the nano-lubricating oil additives,and the tribology mechanism,to seek the synergetic effect between the two.The test results show that the wear resistance of Ni-W-P alloy coating(with heat treatment and in oil with nano-ceramic additives) has increased hundreds times than 45 steel as the metal substrate in basic oil,the friction reduction performance is improved.This research breaks through the bottleneck of previous separate research of the above-mentioned two methods,and explores the combination use of the two methods in industrial field.     

A study on the micro tooling for micro/nano milling

Many researches have studied the micro tools either by simulations or experiments showing that the micro tools play very important roles in micro/nano machining, and micro tool geometries have a direct impact on the final machining quality. Commercially available micro milling tools are usually simply made from downsizing of macro milling tools, which may not be able to be accurately fabricated. Custom micro milling tools have been created by some researchers, but no design criteria for micro milling tools have been introduced. The above factors constrain the development of effective micro milling tools and consequently constrain the researches on micro/nano milling. Based on former researcher??s work, this paper tries to introduce the design criteria for the custom micro tooling. Firstly, the extent typical micro milling tools are studied, and their drawback/limitations are summarized. Secondly, experimental evaluations of the key drawback/limitations are processed. Thirdly, the design criteria for custom micro milling tools are proposed, and corresponding design process is introduced. Then, a new micro hexagonal end mill has been designed based on these criteria. Finally, a polycrystalline diamond micro hexagonal end mill with a diameter of 0.5?mm was fabricated by wire electrical discharge machining, and the evaluation experiments for the hexagonal end mill have been processed on a nano milling center. Experimental results show the newly designed hexagonal end mill can achieve submicron level surface roughness and has simultaneously high-accuracy side and bottom machining capabilities.     

物理气相沉积TiN薄膜疲劳磨损形貌的AFM观测

采用物理气相沉积工艺在高速钢表面沉积TiN薄膜,研究了TiN薄膜的疲劳磨损过程。采用原子力显微镜(AFM)观测分析了表面疲劳点蚀的形貌特征。试验结果表明:较厚TiN薄膜具有较低的疲劳磨损寿命,而较薄的TiN膜层具有较高的疲劳磨损寿命。在试验的初始阶段,磨损轨迹上都出现大量显微凹坑,AFM观测分析可知显微凹坑起源于薄膜表面,呈菱形状。随试验的进行,较薄的TiN薄膜出现典型的疲劳麻坑,而较厚的TiN薄膜在薄膜与基体的界面处形成疲劳裂纹,并出现严重的剥层和断裂。