High Speed Steel Research Articles

The Effect of the Surface Topography of High-Speed Steel Cutting Blades Made Using Various Methods on Their Technological and Functional Properties.

Indication of the proper scope of application of high-speed steels (HSS) produced by conventional methods and powder metallurgy for cutting tool blades requires a thorough assessment of their properties in various cutting conditions. According to common knowledge, the properties of tools made of both types of steel are largely determined by the arrangement of carbide phases. It turns out, however, that the surface morphology of the cutting blades is at least as important for their operational properties. This was already indicated by the preliminary research of the authors of the article, in which it was found that the surface topography significantly affects their durability depending on the applied value of the cutting speed in dry machining conditions and in the presence of a cooling lubricant. As it turned out, contrary to the literature data, blades made of sintered HSS do not have better service properties in all cutting conditions than blades made by conventional methods (e.g., in forging and hot rolling processes). Hence, it was necessary to determine the justified range of use of both types of steel for cutting blades. Cutting blades with a similar chemical composition from conventional high-speed steel and those produced in the powder metallurgy process were tested. Wear curves were determined on the basis of the tests. On this basis, for the assumed value of the blunting index, the tool life of the cutting edges was determined during the cutting of selected structural steel, commonly used for high-strength machine parts. Tests of the cutting ability of the blades were carried out without and with the use of a cooling--lubricating liquid. In order to correctly interpret the obtained results of the wear and durability tests of the cutting edges, verification tests were carried out. A detailed analysis of the research material made it possible to determine the recommended range of applicability of conventional and sintered HSS for the tested case.

Drilling of Cross-Ply UHMWPE Laminates: A Study on the Effects of the Tool Geometry and Cutting Parameters on the Integrity of Components.

Ultrahigh-molecular-weight polyethylene (UHMWPE) is used in the defence industry mainly owing to its properties, such as excellent dimensional stability, excellent ballistic performance, and light weight. Although UHMWPE laminates are generally studied under impact loads, it is crucial to understand better the optimal machining conditions for assembling auxiliary structures in combat helmets or armour. This work analyses the machinability of UHMWPE laminates by drilling. The workpiece material has been manufactured through hot-pressing technology and subjected to drilling tests. High-speed steel (HSS) twist drills with two different point angles and a brad and spur drill that is 6 mm in diameter have been used for this study. Cutting forces, failure, and main damage modes are analysed, making it possible to extract relevant information for the industry. The main conclusion is that the drill with a smaller point angle has a better cutting force performance and less delamination at the exit zone (5.4 mm at a 60 m/min cutting speed and a 0.05 mm/rev feed) in the samples. This value represents a 46% improvement over the best result obtained in terms of delamination at the exit when using the tool with the larger point angle. However, the brad and spur drill revealed a post-drilling appearance with high fuzzing and delamination.

Superior mechanical properties of M35 high-speed steel obtained by controlling carbide precipitation and distribution via electropulsing treatment

Carbide precipitation and distribution always significantly affect the mechanical properties of High-speed Steel (HSS). Thus, the effect of electropulsing treatment (EPT) on the microstructure and mechanical properties of M35 HSS was investigated in this paper. The results show that the electropulsing austenitising then quenched, followed by electropulsing tempered (EQ + ET) samples, showed a 2.3% increase in Rockwell hardness, a 9.7% increase in the bending strength, and the impact toughness increased by 10.3% compared with the conventional heat treatment (CQ + CT) samples. The superior mechanical properties were attributed to the reduction of retained austenite (RA), the uniform distribution of the carbide, and the refinement of the prior austenite grains. Under the action of the current, Ms increased in response to various combinations of alloying elements, thereby reducing the content of RA. Compared to conventional heat treatments, the electropulsing treatment provides additional Gibbs free energy, as well as a large number of dislocations generated by the thermo-compressive stresses, which increase the carbide nucleation sites, resulting in a large number of small-sized carbides precipitating and uniformly distributed in the matrix. The fracture morphology indicates that micro-cracks arise between the carbide and martensite, and the larger carbide provides a preferential path for crack initiation.

Wear Behavior of DLC Coated HSS with Hydraulic Fluids

The worldwide rotary pump market was estimated at around $5000 million in 2020 and the market is supposed to increase by 20% toward the end of 2026, seeing a compounded annual growth rate of 3% over a period from 2022-2026. The scrapping of an engineered component made from non-renewable resources at an early stage in life due to wear goes against the ethics of the conservation of natural resources as the frictional processes lead to dissipation of a part of input energy. In this context many research works focused on analyzing wear behavior using various formulated and vegetable oils but no works investigated on using hydraulic oils as lubricant for wear preventative nature. The objective of the work was to obtain diamond-like carbon coating on high-speed steel samples and test them for better wear preventative behavior with different hydraulic fluids. The HSS ball sample of 12.7 mm diameter were used as a substrate on which the dlc coating was to be developed using then RF-PECVD technique. The developed DLC coating was characterized by conducting X-Ray diffraction which suggested the coating to be of amorphous structure, Raman spectroscopy which determined the content of graphite (sp2 ) to be 47% and that of diamond (sp3 ) to be 53%.Further nanoindentation was conducted to compare the hardness of the high-speed steel sample before and after coating which was 12.22GPa and 35.56GPa respectively. The four ball test was performed to investigate the anti-wear properties of lubricating oil at specific conditions such as higher load, controlled temperature and constant rotating speed of the ball as per the ASTM D4172. The four ball results show that the coefficient of friction for samples reduces by around 36% when test oil 3 is used in uncoated samples and 48% in coated samples. Also, the wear rate for the test oil 3 for coated samples was found to be 0.7381x10-6 mm/Nm, which is the lowest wear rate among the other test oils. The outcome of the project is the reduction of coefficient of friction by 84% with respect to dry condition when test oil 3 is used. Therefore, it can be deduced that test oil 3 stands out as the most effective lubricant among the trio of test oils.In this direction , further work can be carried out by carrying out four ball tests with lubricant oils in combination with additives to it so as to enhance the base oil property and suppress undesirable base oil properties. Fabrication and manufacturing of the vane model can be done to validate the result with the help of experimental work. Key Word: DLC; HSS; Raman Spectrograph; AFM; 4-Ball Test, Hydraulic Oil.

New insights into the microstructure of M2 high-speed steel

In this work, the microstructure of the heat-treated AISI M2 high-speed steel of different initial structural states, wrought and as-cast, was investigated in detail down to the atomic scale, using advanced electron microscopy techniques. Significantly different amount of the secondary carbide particles of a size up to 300 nm in the microstructure of both steels was established and described. In the tempered matrix, the formation of the ultrafine sub-grains with a size in the range of 3–15 nm and the substructure of the α-Fe consisting of nano-sized elongated plates about 200–300 nm in length and 7–30 nm in thickness were proven. Fine dispersions of the secondary hardening carbides along the matrix sub-grain boundaries and inside the carbide clusters were thoroughly investigated and identified as vanadium-rich MC carbide. Extremely fine precipitates at the boundaries of the nano-sized elongated plates in the substructure of the tempered α-Fe were revealed in both steels. The precipitates, regularly dispersed in the tempered matrix and containing carbon, were enriched primarily in iron, molybdenum, chromium, vanadium, and, to a lesser extent, in tungsten, as proven by the combined EDX and EELS analysis. At the atomic scale, the precipitates were found to be mostly disordered solids without a crystalline structure. However, some of the precipitates exhibited traces of crystalline structure, which likely corresponds to Fe21(W,Mo)2C6 phase.

Fine Blanking of Austenitic Stainless Steel Gears Using Carbon-Supersaturated High-Speed Steel Tools

Austenitic stainless steel gears were fabricated via the fine blanking process that can be used for mass production. A carbon-supersaturated (CS)-matrix high-speed steel punch was prepared to minimize the adhesive and abrasive wear damage. Its edge profile was tailored and finished to control the local metal flow around the punch edges and edge corners. This CS punch was utilized in fine blanking the AISI304 austenitic stainless steel gears. Ball-on-disc (BOD) testing was first employed to describe the frictional behavior of the CS tool steel disc against the AISI304 stainless steel balls. SEM-EDX analysis on the wear track revealed that a free-carbon tribofilm was formed in situ in the wear track to prevent adhesive wear via galling on the tool steel disc. No significant adhesive or abrasive wear was detected on the punch edges and punch edge corners after continuously fine blanking with 50 strokes. AISI304 gears were produced to have fully burnished surfaces. Their pitches, widths and circles were measured to evaluate their gear-grade balancing during the fine blanking process. The stabilized gear-grade balancing in JIS-9 to JIS-10 grades was attained for these as-blanked AISI304 gears without finishing processes.

Experimental Investigation of Temperature Distribution in the Chips, Workpiece and Cutting Tool During Machining Operations

High temperature values are encountered during machining processes and these high temperature values have negative influences on the tool, workpiece, chip formation mechanisms, the process efficiency and the quality of surface of the machined parts. These negative influences can be reduced drastically with the use of appropriate cutting tool with suitable depth of cut during machining operations. The studies of these thermal fields in machining are necessary and very important for the development of new technologies aiming to increase the tool lives and to reduce production costs. This work centers on measurement of temperatures in the chips, cutting tool and workpiece during turning and drilling operations using uncoated high-speed steel and coated cemented carbide cutting tools at different cutting speeds and depths of cut to ascertain the more suitable cutting tool and feed rate during machining operations. Although, the direct temperature measurement at the chip-tool interface are very complex, the turning experiments were performed on a lathe machine at varying turning speeds and depths of cut, while the drilling operation was performed on a drilling machine at different turning speeds and depths of cut. All the experiments were carried out at the mechanical Engineering workshop of Federal University of Technology, Owerri. The temperature values of chip, cutting tool and workpiece when working on brass, high-carbon steel and stainless steel were measured using digital thermocouples. The results obtained showed that uncoated high-speed steel cutting tool could not cut stainless steel and high-carbon steel at very high turning speed and depth of cut due to the excessive heat it generated at the contact area, and at very low cutting speed the temperature of the cutting tools were higher than the workpiece irrespective of the cutting tool till an increased cutting speed where temperature of workpiece became higher than the cutting tool. It is recommended that coated cemented carbide on hard materials be used during turning and drilling to ensure a negligible increase in temperature while machining, also monitor speed for required finishing and extended tool life.

Correction: Machinability investigations through novel controlled flushing characteristics in wire electric discharge machining of M42 high-speed steel

Correction: Machinability investigations through novel controlled flushing characteristics in wire electric discharge machining of M42 high-speed steel

Expert methods for improving the effectiveness of planning an experiment to determine the parameters of the technology for casting billets from high-speed tool steel. Part 1. Identification of the complete set of parameters

Methods for increasing the effectiveness of planning an experiment and optimizing the parameters of the technology for casting billets of cutters of a mining combine rotor, based on expert assessments, are considered. In particular, the identification by expert methods of a set of parameters of a priori chosen technology as factors that ensure the production of castings with specified physical and mechanical properties is considered. Keywords: casting technology, high-speed tool steel, experiment planning, expert assessment pavelserenkov@bntu.by, stl_minsk@tut.by, voranava.ts@gmail.com, alexander.chaus@stuba.sk

ВЛИЯНИЕ СТРУКТУРЫ И ТВЕРДОСТИ АБРАЗИВНОГО ИНСТРУМЕНТА НА ПОКАЗАТЕЛИ ШЛИФОВАНИЯ БЫСТРОРЕЖУЩЕЙ СТАЛИ

The operation of flat mortise grinding of high-speed steel blanks are presented. The regularities of changes in the components of the cutting force, the grinding coefficient and the arithmetic mean deviation of the profile of the treated surface during grinding with circles of different hardness and structure are determined. Recommendations on the choice of characteristics of the abrasive tool, modes of finishing and rough grinding of high-speed steel are given.

Methods of Improving the Structure and Properties of High-Speed Steels

Methods of Improving the Structure and Properties of High-Speed Steels

Assessment of self-lubricating coated cutting tools fabricated by laser additive manufacturing technology for friction-reduction

Dry cutting acting as a green machining technology is a promising manufacturing process in industrial applications; however, severe friction under dry cutting conditions aggravates tool wear and reduces tool life. Self-lubricating cutting tools exhibit excellent benefits in improving cutting properties and that can be used in sustainable machining. The complex process, low efficiency and thin coating thickness limit the production and use of present self-lubricating cutting tools with traditional methods. To enhance the lubricating effect and motivate the development of fabrication methods for self-lubricating cutting tools, Ni-based powders dispersed with MoS2 and Al2O3 particles were preset on the tool substrate; afterward, the self-lubricating coatings were deposited by laser powder-bed fusion additive manufacturing (AM) with a nanosecond fiber laser for cutting application. The self-lubricating coatings were characterized, and the friction and cutting performances of the AM self-lubricating coated tools (SLCs) were evaluated by sliding friction and dry machining tests. The results show that the developed SLC tools reduced the friction coefficient by 8.8–11.7%, cutting forces by 17.6–29.6%, and cutting power by 17.3–22.0% compared to conventional high-speed steel cutting tools (HSS). Built-up edge formation and tool wear were also significantly reduced. The observed mechanisms were attributed to the release of MoS2 particles from the coatings forming a lubricating film at the tool-chip interface, while the Al2O3 particles enhanced surface hardness. The results revealed the practicability of self-lubricating coated cutting tools fabricated by laser-based AM for friction-reduction, and that provide a cleaner process for dry cutting applications.

Analysis of Tool Wear and Calculation Results of Hardness Values in St 37 Steel Turning Using Characteristics

The development of lathe chisels is currently more advanced with the creation of carbide, CBN, ceramic, and inserts tool types. However, conventional chisel types, one of which is the HSS (high speed steel) chisel, are still used. ST 37 steel is a low carbon steel type that is easy to forge and easy to machine. The level of precision and surface roughness of the resulting workpiece must be in accordance with the needs. The higher the level of surface quality of the workpiece, the higher the level of precision. The research method we use is to find data, then the data obtained is graphed. From the results of the graph it can be concluded that for the depth of cutting the greater the rotation, the greater the depth. For wear, it can be seen that the wear will be greater if the speed is increased. The results of the hardness test at a medium rotational speed of 490 Rpm, the greater the number of examples, the greater the results of the hardness test experienced on the test material.

Comparison of chemical composition and wear of iron and nickel aluminide coatings applied by plasma spraying

Given such properties as wear resistance, corrosion resistance, heat resistance, contact and cyclic strength, iron and nickel aluminides can be used as coatings in friction pairs for various purposes. The object of research is the process of obtaining plasma-sprayed coatings from powders based on iron and nickel aluminides. The task of research is the determination and comparison of the structure, chemical composition, and wear resistance of coatings from powders of iron aluminide and nickel aluminide, obtained by the method of atmospheric plasma spraying. To reduce the oxidation of powders during spraying, the conditions for generating a laminar plasma jet were created. Such conditions were provided by the specially developed structure of the electric arc plasma gun and the operating parameters of coating spraying. As a result of the correct choice of spraying modes, completely melted splats were formed during the collision of powder particles with the surface. The resulting coatings had a layered microstructure with microcracks and peeling. The porosity and characteristics of the delamination of the coatings depend on both the modes and the spraying technology. Tribological tests of the coatings were carried out under conditions of dry metal-on-metal sliding friction in a pair with high-speed steel. It is shown that the wear of nickel aluminide coatings under these conditions is 2–2.5 times lower than that of iron aluminide coatings. The coefficient of friction of iron aluminide coatings is slightly lower than that of nickel aluminide coatings. The wear of samples made of 30CrMnSi steel is 3–4 times higher than samples with coatings. The difference in the wear of the coatings is explained by the more intense oxidation of iron aluminide in the friction process. Conclusions were drawn regarding the possibility of using the investigated coatings in various friction pairs of structural elements, in particular in the automotive industry

Effects of Nitrocarburization on the Surface Morphology and Tribology of SKH51 High-Speed Tool Steel

Effects of Nitrocarburization on the Surface Morphology and Tribology of SKH51 High-Speed Tool Steel

A framework for the robust optimization under uncertainty in additive manufacturing

This paper introduces a conceptual framework for the robust optimization under uncertainty in the directed energy deposition (DED) of M4 High-Speed Steel. The goal is to identify optimal process parameters for robust manufacturing of printed parts with a stationary melt pool depth and low consumed energy under uncertainty within the multiple layers of a bulk sample. To increase the computational efficiency, a deep learning-based surrogate model is built using the training data generated by a validated high-fidelity DED two-dimensional FE model. The robustness of the optimized result is verified using the Monte-Carlo method and compared with experiments and two other deterministic approaches. Furthermore, we conduct a global sensitivity analysis, which indicates that among six uncertain input variables, the thermal conductivity and the convection have the most significant impact on the melt pool depth variation. This study shows the promising possibilities of the presented framework in optimizing the DED process.

Direct additive manufacturing as spring of new tool steels

Additive manufacturing (AM) is now common in production of metallic matrixes with/without reinforcements (nanoprecipitates) to improve functional and structural mechanical properties of 3D objects. The presence of liquid phase in direct processes allows the possibility to change the conventional chemical composition of materials homogeneously. Powder Bed Fusion (PBF), in which the high nonequilibrium solidification nature resembles a localized high cooling rate but allowing, still the formation nanocarbides in-situ. Thus, it will be the suitable technology to tailor novel functionally gradient metallic materials. Nevertheless, this character is only present in the upper layers due to the shaping being made layer by layer. During shaping, the previous layers undergo post heat treatments contributing for growing the carbide dimension. Hence, metallic alloys can be developed simultaneously with the processing stage by changing the chemical composition by addition of fundamental elements to the matrix powder. In tool steel the improvement of hardening carbide content can contribute to a better performance concerning hardness and abrasion wear resistance. The present study concerns the addition of vanadium powder and allotropes of carbon, in correlation with the partition coefficient between vanadium and carbon in the steel selected - AISI H13, processed by selective laser melting (PBF/SLM), without requiring adjusting the processing parameters. The hardness attained is analogous to high speed steels, since this allows layers with a similar matrix to the wrought tool steel but with higher content of hardening carbide (VxCy). The sustainability of the final product is evident.

A combined method of autoregressive model and matrix factorization for recovery and forecasting of cyclic structural health monitoring data

Structures such as bridges, offshore platforms, wind power facilities, and drilling rigs generate a corresponding periodic structural response under cyclic loads such as solar radiation, tides and sea-land breeze. Data recovery and forecasting are major parts of the work to ensure structural safety using periodic structural health monitoring data. In this context, a combined method of autoregressive (AR) model and matrix factorization (MF) method is presented to reaching the tasks of data imputation and prediction. The combined method with a graph-based temporal regularizer can well capture the cyclic characteristics and random character. The verification of the method is conducted using an in-situ temperature monitoring dataset of a high-speed railway steel bridge. The application of the method for both data recovery and forecasting with structured missing entries is carried out, which indicates the combined method owns outstanding performance in accurately recover missing entries and making predictions. In the last part, the analysis of rank order and length of time lag is made to show its influence on imputation accuracy.

Identification of the effect of strontium and ytterbium addition over magnesium zinc alloy during the drilling process with ARAS and WASPAS techniques

Magnesium (Mg) alloys are widely employed in aerospace and automotive applications owing to their beneficial attributes. Identifying proper process parameters is a critical choice to save costs and increase quality. This necessitates the classification of suitable process parameters in light of numerous competing considerations; hence it must be analyzed by means of the Multiple Criteria Decision Making (MCDM) techniques. This paper handles the MCDM issue using two different approaches namely, the ARAS (Additive Ratio ASsessment) and WASPAS (Weighted Aggregated Sum Product ASsessment). The experiments carried out in Mg Zn10 and adding of Strontium (Sr) and Ytterbium (Yb) were critically evaluated. The independent variable like spindle speed and feed rate were examined by varying the machining tool and coolant supplied. The effect of coated and uncoated carbide was studied with High-Speed Steel. The influence of coconut oil, liquid nitrogen, and vegetable oil over the process parameters was also studied. The responses like thrust force, torque, and surface roughness were studied over the three different materials by varying the numerical and categorical factors. The addition of Yb plays a beneficial effect on all three responses considered. The ideal combination was discovered using ARAS and WASPAS for concomitant reduction of all the considered responses, attained with a coated carbide tool with a spindle speed of 118 m/min. and a feed rate of 0.26 mm/rev. during coconut oil coolant supply over Mg Zn10 Sr2. The ARAS rankings align with the WASPAS rankings in 55.56% of cases, with the interesting observation that both the lower and higher orders are identical. The optimal process parameters for Mg Zn10 were identified as a cutting speed of 56 m/min. and a feed rate of 0.26 mm/rev., using a coated carbide tool and CO coolant. For Mg Zn10 Sr2 Yb2, the study found the optimal parameters to be a cutting speed of 118 m/min. and a feed rate of 0.62 mm/rev., with the use of uncoated carbide and CO coolant.

Tribological properties of high-speed steel surface with texture and vertical fibers

Inadequate lubrication of the two touching surfaces during friction can lead to severe wear, especially in metal cutting. Therefore, a surface with synergistic anti-friction effect of texture and solid lubricant was proposed to improve lubrication. A mesh texture with excellent wettability was prepared on the high-speed steel (HSS) surface by laser, and then nylon fibers were vertically implanted into the grooves of the texture using the electrostatic flocking technology. The friction and wear state of different surfaces (smooth, textured, flocking) under dry/oil-lubricated were studied by a linear reciprocating wear tester. The coefficient of friction (COF) under different working conditions was used to analyze the anti-friction properties, and the wear rate was used to evaluate the wear resistance of the surface. The results showed that the tribological properties of flocking surfaces were better than those of the other two surfaces. This is because the addition of nylon fibers eases shear at the edges of the texture. The broken fibers form a solid lubricating film on the specimen surface, which prevents the surface from being scratched by debris. In addition, it is found that COF decreases with increasing load. Finally, the rapid wettability of the oil droplets on the flocking surface shows the great potential of the surface for lubrication and anti-friction.