Steel Swarf Research Articles

Assessing Stainless Steel Swarf Effect on Limonitic Laterite Sintering Process

Assessing Stainless Steel Swarf Effect on Limonitic Laterite Sintering Process

The impact of impurities on the Al–Fe–C system phase composition changes during sintering

Manufacturing waste can be not only recycled but also utilized as a source of chemical elements and as a component of powder materials. Steel swarf are a complex multicomponent material with a high iron content, while impurities such as carbon can affect the diffusion interaction in the chip and metal powder mixture. In this study, we investigate the diffusion interaction between aluminum and steel swarf using temperature-controlled vacuum sintering. We analyzed the resulting mixture’s microstructure and phase composition, and observed that sintering creates a multiphase structure in which FeAl iron aluminide occupies at least 30 vol. %. Despite the high sintering temperature, we also observed residual aluminum and iron. Incomplete transformation may result form refractory products that inhibit diffusion or impurities that influence the magnitude and direction of the diffusion fluxes. To confirm the impurities’ role in the diffusion interaction kinetics, we developed simulation models of the intermetallic phase growth for a flat and spherical particle embedded in aluminum. The model consider cross-diffusion fluxes in the emerging phase regions and possible effects of impurities on the concentration limit for the new phase’s existence. We derived approximate analytical solutions to analyze the emerging phase growth trends under various model parameters.

Novel approach to recycling of steel swarf using hydrometallurgy

Steel swarf is a hazardous waste which is challenging to recycle due to its high content of heavy metals and cutting fluids and is today commonly landfilled. The swarf can contain up to 80% iron and represents a potential secondary raw material for production of reagents like ferric chloride, which can be utilized in wastewater treatment. This work presents a novel hydrometallurgical approach for recycling steel swarf and production of ferric chloride by selective separation of iron from heavy metals. Swarf containing 69% iron was leached with hydrochloric acid. A leachate containing 24.600 mg/L Fe with 150 mg/L Mn, 12 mg/L Ni and <1 mg/L Cr and Mo was obtained. The oil-based cutting fluids largely remained in the solid residue with only 1% dissolution in the aqueous phase. These findings showed that ferric chloride solutions of 99% purity can be produced from steel swarf in a single leaching step.

Application of Electrocoagulation with a New Steel-Swarf-Based Electrode for the Removal of Heavy Metals and Total Coliforms from Sanitary Landfill Leachate

Sanitary landfill leachate (LL) composition varies according to climate variables variation, solid waste characteristics and composition, and landfill age. Leachate treatment is essentially carried out trough biological and physicochemical processes, which have showed variability in efficiency and appear a costly solution for the management authorities. Electrocoagulation (EC) seems a suitable solution for leachate treatment taking into account the characteristics of the liquor. One of the problems of EC is the electrode passivation, which affects the longevity of the process. One solution to this problem could be the replacement of the electrode by one made of recyclable material, which would make it possible to change it frequently and at a lower cost. The objective of the present work was to evaluate the removal of heavy metals (As, Ba, Cd, Cr, Cu, Fe, Pb, Mn, Ni, Se and Zn) and coliforms from a LL by EC using electrodes made from steel swarf (SfE) up to 8 h. Removal efficiencies of detected heavy metals were 51%(Cr), 59%(As), 71%(Cd), 72%(Zn), 92%(Ba), 95%(Ni) and &gt;99%(Pb). The microbial load of coliforms in leachate was reduced from 10.76 × 104 CFU/mL (raw leachate) to less than 1 CFU/mL (after treatment with SfE) (i.e., approximately 100% reduction). The use of SfE in EC of LL is very effective in removing heavy metals and coliforms and can be used as alternative treatment solution for such effluents.

Experimental Investigation on the Friction and Wear Characteristics of Palm Seed Powder Reinforced Brake Pad Friction Composites

In this research work, palm seed power (0–9 wt%, step of 3%; four composites sample, namely P0, P3. P6, P9) were used to reinforce master batch of friction composite materials containing phenolic resin binder, steel swarf fibre, cashew, alumina, graphite, copper and zinc. The fabrications were as per standard industrial practice via hot compression moulding route. Thereafter, samples were cut and characterized for their tribological characteristics on specifically designed braking dynamometer using grey cast iron disc as per TS 555 and TS 9076 standards. Physical and mechanical properties such as hardness and density of the samples were also determined. Further, multi-criteria-decision-making like Preference Selection Index methods are used to ascertain ranking of material alternatives based on performance criteria. Both the subjective analysis and PSI output are in agreement with each other. Hence, such techniques often found suitable for decision-making or ranking of materials alternatives when performance criteria are of conflicting in nature.

Exploration of plasma treated stainless steel swarf to reduce the wear of copper-free brake-pads

Abstract In recent few years, the environmental issues especially related to the aquatic life are pushing the Friction Industry to develop NAO FMs (non-asbestos organic friction materials) without Cu. Stainless-steel swarf (SSS) having good corrosion resistance was tried as one of the replacing ingredients for Cu in FMs in Authors’ laboratory in earlier work. It proved to have a great potential for Cu replacement almost in all the performance properties but at the cost of slightly lower wear resistance and hence the theme of current research was to enhance the wear resistance capability of SSS. Hence, in the present study SSS were treated with air-plasma and used in brake-pads. Thus, two types of brake-pads with the identical composition but differing in type of SSS 10 wt % (treated and untreated) were tribo-evaluated on a full-scale brake inertia dynamometer and treated SSS containing pads exhibited higher wear resistance (approx. 10%) confirming success of the treatment, first time explored for the friction materials. Enhanced adhesion with resin was the main cause for the improved tribo-performance.

Strength and deflection characteristics of concrete reinforced with steel swarf

This paper reports the strength characteristics of concrete reinforced with steel swarf at varying percentages. A total of forty-five concrete specimens were investigated; with a mix proportion of 1:2:4 and water-cement ratio of 0.55, fifteen numbers each of 150mm concrete cubes, 150x300mm concrete cylinders and 150x150x750mm beams, were cast and tested for density, compressive, tensile and flexural strengths. The results showed that workability of Swarf Reinforced Concrete (SRC) is not significantly affected at 0.5% steel swarf content but decreased as the percentage of steel swarf increased. The density of SRC increased as the percentage of fibres increased, due to the material property of the steel swarf. The compressive strength of swarf concrete as compared to normal concrete was found to increase by 1.7%, 4.8% and 5.6% for 1%, 1.5% and 2% swarf content respectively. The obtained increase in the tensile strength was 5.2%, 3.9%, 13% and 26% for 0.5%, 1%, 1.5% and 2% swarf content respectively. Using regression analysis, Index models for compressive strength and tensile strength with respect to the swarf content was developed at high coefficient of correlations (R2 values) of 0.9398 and 0.9601 respectively. The maximum failure load recorded for swarf concrete was 2.5 times higher than that of plain concrete. The significant increase in the failure loads for the 1.5% and 2% steel swarf content is an indication that there was good bond between the concrete and the steel swarf. The maximum deflection of 0.57mm was recorded for swarf concrete beams. This is an increase of 103% compared to plain concrete beams. The SRC is able to sustain further deformation under increased load; this is as a result of increased load carrying capacity and ductility of the beam section, which is due to the strength and ductility properties of the embedded steel swarf.

A step towards replacing copper in brake-pads by using stainless steel swarf

Multi-functionality of copper (Cu) in friction materials renders its replacement extremely difficult. However, rising ecological concerns and the imminent ban on its usage make it mandatory to look for an efficient substitute. The present paper explores a possibility to replace particulate Cu filler by stainless steel swarf (SSS) in the brake-pads. A series of five realistic multi-ingredient brake-pads containing SSS as a focussed ingredient was developed by increasing its amount from 0 to 20 wt% in the step of 5%. In another set of pads 10% of SSS was replaced by 10 wt% Cu n particulate form keeping all ingredients same to compare the performance of two fillers. These pads were characterized for their physical, mechanical and tribological properties. Tribo-performance using realistic test parameters was evaluated on the brake inertia dynamometer as per JASO C 406 standard. It was observed that with an increase in the amount of SSS, almost all the properties of brakes pads, including wear resistance improved significantly. Nonetheless, Cu- containing pad proved slightly better in recovery ratio and wear performance by 10%, but inferior in the case of fade µ (µ-coefficient of friction) and recovery µ. Worn surface analysis with scanning electron microscope (SEM) confirmed that SSS had poor interfacial adhesion with the matrix which led to a higher wear of SSS filled pads as compared to the Cu filled pads.

The Mechanism of Metal Dispersion in the Presence of a Solid-Phase High Molecular Compound

The mechanism of dispersion of metals in the presence of high molecular compounds is shown on the example of grinding high speed R6M5 steel swarf. It was shown that metal pulverization is more energetically favorable in the presence of a mechanically degradable polymer than in the presence of low-molecular weight surfactants.

Chemical Reduction of Nitrates In The Wastewater From 2-EHN Production

Abstract The objective of the research was to determine the efficiency of nitrate removal from wastewater from 2-ethylhexyl nitrate production using chemical reduction process. The average concentration of nitrate nitrogen in raw wastewater was about 5.2 g/dm3. The processes of chemical reduction were conducted both in batch and continuous flow reactor under strongly acid conditions using two reducers: steel swarf, as a source of iron, and technical grade urea. In the batch process the maximum degree of nitrate removal equal to 24.4% was obtained in the process modification with pre-digesting of the steel swarf in a concentrated acid. The continuous process was carried out in a single, two- and three-stage system. In order to increase the efficiency of reaction the wastewater was heated to a temperature 70–75°C. The impact of degree of wastewater recirculation, temperature and quantity of steel swarf on the reaction efficiency was evaluated. In optimal conditions (pH&lt;1; temperature in the range of 70–75°C) the maximum degree of nitrate removal equal to 92.2% was obtained in a two-stage system at six times of recirculation of wastewater. However, for economic reasons as the best modification it was a triple-stage system at tenfold recirculation (effectiveness 89.3%), in which the wastewater was heated only to 34°C, i.e. the actual temperature of wastewater from the production of 2-EHN.

Metal Grinding in the Presence of Mechanically Degradable Polymer

Grinding of metal swarf in the presence of a mechanically degradable high-molecular compound intensifies the size-reduction and plasticizing processes and is accompanied by reduction reactions and desulfurization of metal particles. Mechanically degradable organics are used as solid-phase high-molecular compounds to promote metal grinding. A high-energy vibrating mill is employed to grind steel swarf, a single-crystal diffractometer for X-ray diffraction, and an infrared laser pyrometer to measure the temperature of the reactor walls during grinding. Polymethyl methacrylate is experimentally chosen as a high-molecular compound to generate active low-molecular components. The grinding of high-speed steel swarf together with the high-molecular organic compound leads to metal disintegration, which is a more energy-favored process that that occurring in the presence of low-molecular surface-active agents. The experiment has also demonstrated that there is no need to use labor-intensive annealing of the powder to eliminate mechanical work hardening since the vibration treatment of swarf in the presence of a degradable polymer leads to metal plasticizing. The time factor is used to describe the removal of adsorbed sulfur and that contained in steel from the metal and to describe the reduction of oxide films by the cracking products during mechanochemical treatment.

Untersuchung der Mikrostruktur asbesthaltiger Bremsbeläge und Möglichkeiten der Asbestsubstitution / The Microstructure of Brake Lining Materials Containing Asbestos and Possible Asbestos Substitutes

Asbestos-based brake linings from two Iranian manufacturers were investigated using laser scanning and electron microscopy. The composition specified by the manufacturers was confirmed and the arrangement of the various components both before and after braking tests documented. It was shown that the steel swarf particles form primary contact points onto which layers of wear particles adhere. In the as-produced condition and after grinding, numerous fibres of asbestos were observed. After braking trials however only relatively innocuous broken fibre particles were found on the surface of the lining material.

Milling Machine Processes Aluminium Swarf Efficiently

ALUMINIUM swarf is produced in a machine tool much faster than steel swarf, and its removal is often a headache for manufacturers. One sub‐contractor which has this problem firmly under control is Manchester‐based Aluminium Supply (Aerospace) Ltd., whose two Bridgeport vertical machining centres are able to process efficiently the large amounts of aluminium waste which they create.

Effect of method of processing on the physicomechanical and technological properties of powder from ShKh.15 steel swarf

Effect of method of processing on the physicomechanical and technological properties of powder from ShKh.15 steel swarf

Optimization of the comminution process in the industrial manufacture of powder from steel swarf

In the manufacture of powder by comminution of steel swarf, the specific shape of the latter's elements affects certain aspects of the comminution process and its characteristics in various stages of transition from swarf to powder. Using different devices in different stages of the comminution process, it is possible to increase productivity and reduce the amount of power expended. A further decrease in power expenditure can be achieved by combining comminution operations performed in open and closed cycles.

Assessment of the contamination of high-speed steel swarf with cutting fluid and its cleaning before conversion to powder

Assessment of the contamination of high-speed steel swarf with cutting fluid and its cleaning before conversion to powder

Method of manufacture of high-speed steel from swarf and its properties

The feasibility is demonstrated of direct processing of fine high-speed steel swarf by a powder metallurgy technique including prepressing, extrusion, and heat treatment operations The process developed enables sintered steel to be produced possessing properties similar to those of standard steel. The true mechanical properties of standard (cast) and sintered (extruded) steels were determined, with the aid of the theory of plasticity of porous materials, by plotting their deformation diagrams. It is shown that the above theory is applicable to materials possessing coarse structural porosity. Quantitative discrepancy was found between compression and tensile curves, resulting from the presence in such materials of isolated nonmetallic inclusions and from the discontinuity of their microstructure, which may be regarded as initial porosity.

The recycling of cast iron borings and steel swarf

The paper indicates the inherent difficulty and wastage in remelting untreated cast iron borings and steel turnings and the advantages of hot briquetting these materials to provide a more amenable and productive furnace charge. Compressive strength and drop tests on typical cast iron and steel briquettes are reviewed. The processes for drying and heating the charge, hot forging the briquettes, incinerating the volatile contaminants and filtering the discharge gases are described and illustrated.

Effect of titanium carbide additions on the milling, pressing, and sintering of tungsten-molybdenum-vanadium steel powder

1. A study was made of the milling of high-speed steel swarf with a titanium carbide addition and of the production of dense blanks from the resultant composite powders. 2. It is shown that titanium carbide additions intensify the comminution of high-speed steel swarf and result in the formation of structures with evenly distributed fine (2.0–2.5 μ) carbide grains. 3. The addition of titanium carbide raises the hardness of high-speed steel from 62 to 68 HRC.

Effects of niobium carbide additions upon the production and properties of sintered high-speed steel

1. A study was made of the comminution to powder, in a rotary ball mill, of R18 high-speed steel swarf containing niobium carbide additions and of the subsequent processing of the resultant composite powders to dense blanks. 2. Niobium carbide was found to intensify the swarf comminution process: In powder milled for 48 h, the presence of 5 vol.% NbC increased the yield of the −0.25-mm fraction from 46 to 81% and that of the finest (−0.04-mm) fraction from 35 to 45.5%. At the same time, the mean particle size decreased from 0.31 to 0.18 mm. 3. A study was made of the pressing and sintering of the high-speed steel powder with niobium carbide additions. Strong compacts with a relative density of 70–73% were produced by pressing the powder, with a rubber addition, under a pressure of 8–10 tons/cm2. 4. Sintering, in the absence of a liquid phase, for 60 min at 1250°C in very dry hydrogen was found to yield blanks with a relative density of more than 95%. The blanks were characterized by a fine-grained structure and a mean carbide grain size of 1.5–2μ. 5. The addition of niobium carbide affected the size of the austenitic grain, reducing it from 18μ at 1 vol.% NbC to 7μ at 5 vol.% NbC. 6. The introduction of niobium carbide raised the hardness of the sintered steel, from 59 HRC (without NbC) to 65 HRC at a NbC content of 5 vol.%.