Thin layer activation for measuring fretting wear and material transfer in iron alloys

An important difference between fretting wear and macroscopic wear processes lies in the amounts of wear volume. Because of the small relative displacements in fretting wear the wear volumes are much smaller than in (classical) macroscopic wear processes. Classical wear measuring techniques such as weighing and 2D-profilometry often fail to determine the fretting wear volumes. Their sensitivity as well as their accuracy are inadequate. 3D-profilometry partially solves this problem but the obtained wear results do not take eventual material transfer between the test specimens into account. In this work thin layer activation (TLA) is presented as a potentially powerful tool for quantitative fretting studies, especially in relation to material transfer. In contrast with the other mentioned wear measuring technique TLA allows measurements of very small amounts of wear as well as material transfer between the test specimens. Preliminary results are reported for steel specimens. A surface zone of 7 mm² of one test specimen, in which the wearing zone during the fretting experiment is situated, is irradiated with protons from a cyclotron. As a result of a nuclear reaction the iron in the irradiated test specimen forms radionuclides, mainly cobalt-56, in a surface layer of 260 μm depth. The amount of cobalt-56 as compared to iron is negligible so that the physical and chemical properties of the irradiated zone remain unaffected. Measuring the gamma rays of cobalt-56 in the wear debris gives quantitative information about the wear volume and measuring the mating surface gives information on the transfer volume.     

Application of thin layer activation to measuring tool wear in metal cutting

Thin layer activation (tla) as a method for measuring tool wear is discussed in the context of previously available methods and shown to be more accurate, quicker and less costly. The concept of tool wear resistance, a function of cutting time and wear, obtained experimentally by tla, is introduced and shown to be a useful aid to determining tool life     

Health hazards from cutting fluids

Health hazards known to face workers in machine shops are reviewed. The causes, incidence, and prevention of dermatitis, acne, folliculitis and cancer are discussed. Attention is drawn to some potential but not proven hazards.     

超声处理乳化液在金属切削中的应用

为了减少机械加工中乳化液的使用量,达到节能减排的目的,对乳化液进行了超声波处理,并用它做切削液进行了正交切削试验,研究了乳化液流量、处理时间、水质、乳化液浓度等参数对主切削力的影响,给出了正交试验优化后的各因素取值为:流量2.0L/min,处理时间1.5h/L,水质用自来水,浓度10%.     

先进技术的最佳解决方案--Mobil切削液

从动力传送的早期,Mobil的名字就已经与成功联系起来了。该公司先行开发了合成润滑技术,该技术已用于许多惹人注意的工程项目,其中包括航天飞机、协和号、猎兔狗喷气式飞机和波音777。 Mobil有关运输产品的成功使它能够投资开发它的工业产品,例如最近推出的Mobilmet XLM系列纯切削液。2000年4月Mobil于Birmingham的国家展览中心(NEC)     

Benzylamines in cutting fluids: inhibitory properties

Benzylamine and 20 related compounds were evaluated as preservatives in metal working fluids, n-benzylamine, n-methyl-o-chlorobenzylamine, n-methyl-p-chlorobenzylamine and p-methoxybenzylamine had excellent antimicrobial properties against mixed bacterial and fungal inoculations. Significant activity was also noted with dl-α-methylbenzylamine, n-methyl-m-chlorobenzylamine, 3,4-dimethoxybenzylamine, n-ethylbenzylamine and n-butylbenzylamine. The addition of disodium edta to the test vessels enhanced preservative action. Public health and environmental concerns of benzylamines are briefly reviewed.     

Water based cutting fluids and human health

The question of whether machining operations and exposure to water-base cutting fluids constitutes a human health problem is complex. The literature on the subject is hard to find; it is difficult to create study groups of workers large enough to develop statistically significant information; there is often a lag phase of several years between exposure to cutting fluids and the appearance of a medical problem; public attitudes restrain research on the subject; the identity of the chemicals involved is not completely known and animal studies involving cutting fluids are not adequate at present. Until adequate information is available, efforts should be directed towards minimizing exposure and controlling the microbial loads found in these products.     

Mechanical testing of hydraulic fluids

The antiwear properties of hydraulic fluids are important because hydraulic pump and motor wear is costly. While international hydraulic fluid performance standards continue to be developed, e. g., the ISO/TC28/SC4 committee's draft ISO DIS 11158 ‘Specifications for mineral oil hydraulic fluids’, the normal hydraulic fluid performance specifications represent minimum requirements. Performance specifications for nonmineral oil hydraulic fluids are also being developed. Typically, both the user and the fluid manufacturer possess insufficient objective information about the antiwear properties of special fluids, e. g., environmentally acceptable hydraulic fluids (EAHF) or fire‐resistant hydraulic fluids (FRHF) for use in hydraulic equipment such as axial‐piston pumps, vane pumps or radial‐piston motors. Manufacturer's specifications must therefore be determined. The required lubrication properties can be determined by either laboratory pump tests or a field trial, often at the customer's expense. The lubrication properties of a hydraulic fluid should ideally be determined under conditions that are equivalent to field practice. This paper will discuss the use of the vane pump test and the FZG gear test to gauge ‘recommended’ hydraulic fluid performance; many non‐mineral hydraulic fluids, such as environmentally acceptable hydraulic fluids, fire‐resistant fluids or synthetic hydraulic fluids, cannot be used in axial‐piston systems based only on results obtained with these tests, and additional testing is always required. Proposals are made for testing of such fluids on a variable‐load test rig. These tests are done with axial‐piston pumps, or other similar displacement systems, and are intended to determine the industrial suitability of non‐mineral hydraulic fluids.     

Influence of cut layer on cutting

The contact of the chip with the tool’s front surface in cutting is analyzed by numerical modeling. The high-pressure zones and buildup at the tool’s contact surface are studied. The influence of plastic instability of the chip surface and vortex deformation modes on tool wear is considered.     

Choosing the basic system in the application of the thin layer activation technique to cutting tools

Cemented carbide tools made radioactive by irradiating them with ³He²⁺ ions were used to measure tool wear. The detector used to monitor the radioactivity incorporated a sodium iodide scintillation counter. The use of ³He²⁺ ions for irradiation is preferable to that of protons. Consideration of the characteristics of commercially available radiation detectors showed that the use of a scintillation counter was most appropriate for this application.     

Inhibitory properties of 1,3-propanediols in cutting fluids

It has been shown that 1,3-propanediol compounds exhibit antimicrobial properties in cutting fluids, two of the most active compounds being 2-nitro-2-bromo-1, 3-propanediol and 2-nitro-2-ethyl-1, 3-propanediol (nepd). Since the former chemical is well known as an antimicrobial agent, nepd was selected for additional studies. It was found that the antimicrobial properties of nepd were increased by the presence of edta, that it did not markedly interfere with the antimicrobial properties of cutting fluid preservatives and that it combines well with certain amines — such as ethanol-amines, propanolamines, butanolamine and butylamines — to produce mixtures with improved inhibitory properties.     

Microbial contamination of cutting fluids and associated hazards

In this paper, an experimental investigation into the microbial contamination of cutting fluids is presented. The paper confirms the laboratory based results of the fluid biocontamination by culture and identification of the micro-organisms, and their ability to survive in the workshop fluid systems. Direct and/or indirect associations of the identified micro-organisms with the potential health hazards are pointed out.