Metal chips preparation for utilization using advanced reagents

The article touches upon the problems of utilization of metal chips containing residues of cutting fluids. The research results are shown for nickel alloy chips washing to remove cutting fluids with the use of various reagents available on the current market. In the course of the research, an original colorimetric express method for assessing the contamination of metal chips was developed, which allows quickly and efficiently establishing the quantitative drop in the cutting fluids content in the chips after the washing. Conclusions are made as to the most effective reagent from the point of view of economics and quality of cutting fluid removal.

Explanations for the development of a novel universally inside pipe separator for dismantling (contaminated) pipelines

During the operation and dismantling of nuclear facilities, individual pipelines must always be removed due to leaks because of the end of their maximum service life or the dismantling of the plant. In practice, this activity, which at first glance appears simple, is associated with many challenges due to limited space or the fact that the pipelines run through walls, despite various solutions that are available on the market. Therefore, the aim of the joint research project “RoTre” (Development of a novel universally inside pipe separator for dismantling contaminated pipelines) between KIT, Siempelkamp NIS Ingenieurgesellschaft mbH and RWE Nuclear GmbH is the development of an innovative and competitive inside pipe separator for use in decommissioning and dismantling of nuclear facilities with a wide range of applications for various pipe diameters, wall strengths and materials (Fig. 1). An amendment will be the forward cleaning, whereby metal chips or other components can be captured continuously. Besides the dismantling in areas which are difficult to access, such as pipelines set in concrete or pipelines that cannot be drilled over their full length, dismantling should be possible in air and under water. After application, the system can be decontaminated. In order to separate pipes made out of different materials with various wall thicknesses, the development of a universally applicable test stand is planned in order to achieve the scientific work objectives. Among other things, it should be determined whether a sawing or an abrasive cutting process is more suitable for cutting inside pipes. Building on this, the parameters of the separation process are tested in a parameter study to achieve the smallest possible process forces with a universal applicability. Relevant parameters are the geometry parameters of the cutting unit like the saw tooth shape, the composition of the cutting wheel, as well as the process parameters in the form of infeed, cutting speed and tool speed. The cutting quality achieved by the different tools with the setting of the machine parameters is also an evaluation criterion for the selection of the cutting process.

From Machining Chips to Raw Material for Powder Metallurgy—A Review

Chips are obtained by subtractive processes such as machining workpieces and until recently considered as waste. However, in recent years they are shown to have great potential as sustainable raw materials for powder technologies. Powder production from metal chips, through the application of solid-state processes, seems to be an alternative to conventional atomization from liquid cooled with different fluids. However, chip material and processing have an essential role in the characteristics of powder particles, such as particle size, shape, size distribution and structure (4S’s), which are essential parameters that must be considered having in mind the powder process and the metallurgy applications. Moreover, different approaches refereed in the application of this new “powder process” are highlighted. The goal is to show how the actual research has been transforming subtractive processes from a contributor of wastes to clean technologies.

Design and Research of Grinder Cooling Device Used for Mechanical Numerical Control Machining

This paper introduces design method and working principle of grinder cooling device for mechanical numerical control machining. By analyzing the problems of grinder cooling in mechanical numerical control machining, technical solutions for the problems, model construction and specific implementation pattern are proposed. Compared with the traditional cooling device, this device is simple to use, uniform in cooling, and has better coolant cooling effect. While cooling, it removes a part of metal chips and impurities, avoidingadverse effect on accuracy of the machined surface, whichprovides important guidance for production practice.

Effect of Metal Lathe Waste Addition on the Mechanical and Thermal Properties of Concrete

The amount of steel chips generated by lathes and CNC machines is 1200 million tons per year, and they are difficult to recycle. The effect of adding steel chips without pre-cleaning (covered with production lubricants and cooling oils) on the properties of concrete was investigated. Steel waste was added as a replacement for fine aggregate in the amounts of 5%, 10% and 15% of the cement weight, which correspond with 1.1%, 2.2% and 3.3% mass of all ingredients and 0.33%, 0.66% and 0.99% volume of concrete mix, respectively. The slump cone, air content, pH value, density, compressive strength, tensile strength, tensile splitting strength, elastic modulus, Poisson’s ratio and thermal parameters were tested. It was observed that with the addition of lathe waste, the density decreased, but mechanical properties increased. With the addition of 5%, 10% and 15% metal chips, compressive strength increased by 13.9%, 20.8% and 36.3% respectively compared to plain concrete; flexural strength by 7.1%, 12.7% and 18.2%; and tensile splitting strength by 4.2%, 33.2% and 38.4%. Moreover, it was determined that with addition of steel chips, thermal diffusivity was reduced and specific heat capacity increased. With the addition of 15% metal chips, thermal diffusivity was 25.2% lower than in the reference sample, while specific heat was 23.0% higher. No effect was observed on thermal conductivity.

AA7075-ZrO2 Nanocomposites Produced by the Consecutive Solid-State Process: A Review of Characterisation and Potential Applications

Solid-state recycling is a direct conversion method for producing metal chips, whereas the materials are plastically deformed into the final product without melting, offering lower energy consumption and metal waste. This technique was reported for fabricating aluminium-zirconium oxide (Al-ZrO2) composite and it was widely used to avoid metal chips bounding at high temperatures during the extrusion process. Aluminium alloy (AA7075) is known for its high yield strength of more than 500 MPa under optimum ageing conditions. However, AA7075 can be further reinforced by zirconium oxide nanoparticles when needed for high-performance applications. Hot extrusion is used to obtain better mechanical properties of composite materials. The equal channel angular pressing (ECAP), a severe plastic deformation technique, was recently used to produce bulk and light recycled metal chips, such as porosity-free and ultra-fine-grained aluminium nanocomposites (ANCs). Heat treatments (HT) and ECAP post hot extrusion are mostly incorporated to improve tribological and mechanical properties and aluminium nanocomposite bonding efficiency. In this review, ANCs’ fabrication by the hot extrusion technique and the effects of ZrO2 nanoparticle are duly summarised and discussed. Furthermore, this review emphasises the importance of using HT and ECAP techniques to acquire better metal alloy incorporation, such as AA7075-ZrO2. Interestingly, owing to the lightweight properties and superior performance of AA7075-ZrO2, it was reported to be suitable for fabricating many drones’ parts, military equipment, and some other promising applications.

Improvement of efficiency of metal recycling in metallurgical production

The article deals with the most effective primary utilization and subsequent processing of the main waste of machine-building enterprises-metal chips. To solve the above problems, the recycling of metal waste the most effective method is a comprehensive approach to the conditions of machine-building enterprises working in the conditions of the automated production consists of solutions to several problems, the main of which are submitted to the necessary properties of the chips produced and optimization of the technological equipment used for initial processing and subsequent briquetting of the chip. The solution of the problem of obtaining chips of the specified characteristics after the analysis of existing methods of its solution is proposed to be performed by applying the method of preliminary local physical impact on the surface of the workpiece. The proposed method makes it possible to obtain chips of such parameters that will meet the technical conditions of the type of automatic line for its processing and disposal, which is available in a particular production. The problem of optimization of the technological line of primary processing of chips is proposed to be solved on the basis of preliminary engineering analysis of chip crushing devices, which allows you to choose the optimal geometry of the cutter inserts depending on the type and material of the chips being crushed. The proposed set of measures should help machine-building enterprises to increase the profitability of production.

Material model assessment in Ti6Al4V machining simulations with FEM

Ti6Al4V alloy is a well-known difficult-to-cut material used in different industrial applications, to achieve the expected component quality, proper definition and control of the machining process parameters must be accomplished. To address this problem, simulations with finite element method (FEM) seem to be an interesting engineering tool to model and optimize machining processes. Nevertheless, the model capability in capturing the behaviour observed in real machining processes is associated with the definition of the model and parameters that describe the workpiece flow stress. This contribution aimed to study the performance of built-in AdvantEdge-2D™ material laws applied in Ti6Al4V orthogonal cutting simulations under dry conditions. The numerical models were created under three levels of cutting speed, a constant feed rate and depth-of-cut, a variable tool rake angle (of 20° and −6°/0°), but also using four Ti6Al4V constitutive laws, namely, one suggested in AdvantEdge™ library, a Johnson-Cook (JC) model, a Power law (PL) and a PL coupled with ductile damage model. Experimental results were used to assess the numerical models’ accuracy in predicting the machining forces and metal chips. Satisfactory results regarding the machining forces prediction were achieved with all material laws, yet when the damage criterion was coupled with the constitutive laws (PLD and AE standard material law), the simulations were also were able to achieve the expected chip morphology (serrated metal chips).