Steel Workpiece Research Articles

Cutting temperature of graphene reinforced ceramic cutting tool inserts during dry turning of hardened steels

The amount of heat generated during machining operations under high speed and depth of cut inherently produces high temperatures at the cutting zone. Therefore, the temperature generated at the cutting junction of the tool and workpiece is a crucial parameter in determining the quality of the finished product. The effect of the generated cutting temperature, especially at elevated temperatures, primarily affects both the workpiece and the cutting tool. Knowledge of the cutting temperature generated at the tool tip can improve tool life and machining performance. In this work, turning operations were performed on a hardened steel workpiece of grade EN24 and EN36 using alumina-graphene composite ceramic tool inserts under different machining conditions on a precision lathe without coolant (dry machining). The maximum temperatures generated (offset temperature, i.e., 4 mm away from the tool insert tip) at the tool insert were measured during the turning of hardened steel workpieces with the aid of a calibrated thermocouple. A study was also conducted on the effect of different weight percentages of graphene in alumina ceramic tool inserts on the generated offset temperatures. During the machining of both the EN24 and EN36 samples, it was clearly observed that offset temperatures generated at composite tool inserts reinforced with 0.35 wt% and 0.45 wt% of graphene were lower at all machining conditions compared to offset temperature values generated at 0.15 wt%, 0.25 wt%, 0.55 wt%, 0.65 wt% graphene-reinforced alumina ceramic tool inserts, as well as pure alumina tool inserts.

Finite element simulation and experimental analysis of B4C‐TiB2‐SiC ceramic cutting tools

AbstractHere, cutting properties and wear mechanism of the home‐made B4C‐TiB2‐SiC ceramic cutting tools in turning of AISI 4340 steel workpieces were studied through a combination of finite element simulation using Deform‐3D software and turning experiments. Simulation results show that cutting parameters have significant effects on the main cutting force and tool temperature of the B4C‐TiB2‐SiC cutting tool. The optimal cutting parameters for the ceramic cutting tool are cutting speed of 300 m/min, depth of cut of .3 mm, and feed rate of .1 mm/r. Experimental results show the cutting length of the B4C‐TiB2‐SiC cutting tool is about 101 m, which is 21.0% and 32.9% larger than that of the home‐made B4C‐TiB2 ceramic cutting tool and commercially available tungsten carbide tool, indicating that the B4C‐TiB2‐SiC cutting tool has a desired service life. The surface roughness of the workpieces processed by the B4C‐TiB2‐SiC cutting tool is 2.43 µm, which is 29.4% lower than that of the workpieces processed by the B4C‐TiB2 cutting tool, indicating that the B4C‐TiB2‐SiC cutting tool has a satisfying machining accuracy. Wear forms of the B4C‐TiB2‐SiC ceramic cutting tool involve craters, chipping, and flank wear, and the main wear mechanisms are abrasive, adhesive, oxidative, and diffusion wear.

The grindability performance and measurement of surface functional parameter capabilities of difficult-to-machine tool steel under tangential ultrasonic-vibration-assisted dry grinding

The grinding performance of the finished component is significantly affected by the consistency and durability of the grinding mode used in its formation. The current research attempted to evaluate the influence of worktable feed rate and ultrasonic vibration amplitude on grinding outcomes responses such as ground forces, ground surface morphology, surface roughness and topography, surface bearing index, core fluid retention index, grinding temperature, and chip morphology. Experimental works were performed on a setup that was indigenously developed and manufactured. Experiments were conducted on AISI D2 tool steel workpiece material under the tangential ultrasonic-vibration-assisted dry grinding (TUDG), common dry grinding (CDG), and common flood grinding (CFG) modes to compare the effectiveness of each mode in terms of the responses of the grinding outcomes. A comprehensive comparative analysis of each grinding mode is demonstrated, along with observations of changes in the output responses under the effect of the investigated grinding parameters. Findings showed that under identical conditions, the TUDG mode’s surface bearing index and core fluid retention index was higher than that of the CDG and CFG modes. To elucidate these findings. Besides, small, thin chips generated in TUDG mode indicate the ease of grinding of AISI D2 tool steel.

Research on Deep Hole Machining Based on Aircraft Landing Gear

A landing gear is the main large bearing structural part of an aircraft. The change of material and structure makes the processing of the aircraft landing gear more difficult. Aiming at the structural characteristics of the aircraft landing gear deep cavity, the deep hole processing technique of a 300M steel workpiece was studied. A separated NC deep hole drilling and boring machine was adopted to process the workpiece. Cavity hole special cutting tools were introduced. Fixture and sealing mode were improved. NC programs were optimized. Thus, the processing problems of deflection, vibration, chip breaking and chip removal were solved. The workpiece with width to diameter ratio greater than 10 and surface roughness of hole is 3.2 μm was successfully machined by machining experiment, and the high efficiency machining of deep hole of ultra-high strength steel was realized. Thus the theoretical foundation is laid for the machining of complex cavity deep holes for cutting high-strength alloy materials.

Cold Metal Transfer in the Additive Formation of High-Alloy Steel Workpieces. Part 1

Cold Metal Transfer in the Additive Formation of High-Alloy Steel Workpieces. Part 1

Mathematical Modelling and Multiresponse Optimization to Minimize Surface Roughness in Drilling Custom 450 Stainless Steel

In the present study, drilling tests were carried out on Custom 450 stainless steel workpieces. The influences of control factors (cutting speed-Vc, feed rate-f and drill bit geometry-D) on the drilled holes’ surface roughness (Ra) and on the size of adhering workpiece (AW) to the drill bit was examined. The results obtained from tests designed based on the Taguchi’s L16 orthogonal array were analysed using ANOVA and grey relational analyses (GRA). Therefore, the control factors and their levels were optimised simultaneously for the quality characteristics (Ra and AW). In addition, mathematical models were also developed using Response Surface Methodology (RSM) in order to estimate the quality characteristics. The used drill bits were examined under digital and scanning electron microscopes and EDX analysis was also carried out on the drill bits. The experimental results showed that the Ra and AW increased with increasing the f. It was also seen that increasing the Vc resulted in decrease in the size of adhering layer and that the drill bit wear became clear at the highest Vc of 60 m/min. According to the ANOVA results, the most effective control factor on Ra was f with 93.11% and Vc with 58.14% on AW. GRA analysis revealed that the most influential control factor was the f and that the optimum levels were 60 m/min Vc, 0.005 m/min f and drill bit 4.

Effect of process parameters on surface roughness of NiCu alloy in fluid jet polishing

Fluid jet polishing is a non-contact and flexible type of polishing process for generating high-quality surface finish in optical dies manufactured from ductile materials like Monel-400 (NiCu alloy). This article presents an investigation of fluid jet polishing of Monel-400 die material with a 3D printed Ti64 tool and silicon carbide abrasive slurry with an effect of pressure, stand-off distance and polishing time on the surface finish. The response surface methodology method was used to develop the experimental plan and Analysis of Variance analysis was carried out to identify the optimized values of the control parameters to maximize the percentage change in surface roughness. The validation of the developed regression model was done by polishing the plate of Monel-400 using the optimized parameters: the pressure of 9.6 bar, stand-off distance of 32.2 mm and polishing time of 170 s. The optimized fluid jet polishing parameters successfully generated a surface roughness of 90 nm in one of the experimental tests. The predicted results were in close agreement with the experimental results. Further improving the polishing efficiency, the optimal feed rate of 20 mm/min was used to polish the 40 mm × 50 mm Monel-400 plate, the surface roughness was reduced from 300 to 80 nm in 10 multiple passes showing the reduction in peaks and valleys with the surface improvement of 73.33%. The result shows that the fluid jet polishing process tends to improve the life span of Monel-400 die steel workpieces which is beneficial for the application of various industrial components such as optical lenses, marine applications, automotive components and defence applications.

Surface Roughness of Workpiece and Temperature Effects of Cutting Fluids on High-Speed Steel Tool

The major needs in machining are high material removal rate, good work surface finish and low tool wear. However, machining process often encounter tools wear problem which leads to increased product cost and poor quality. The aim of the study is to determine the effects of surface roughness and temperature of the cutting fluids on high-speed steel tool. High-speed steel (HSS) cutting tool was used on Colchester triumph space bed Centre lathe to work on a mild steel using cutting fluid such as soluble oil, liquid soap, and engine oil. The feed rate, spindle speed and depth of cut of the mild steel work piece were kept constant. The surface coarseness and temperature of the machine was examined with the three types of cutting fluid used. This result indicated that among the three cutting fluids used in the study, the liquid soap has the best temperature reduction on the chips (38.02℃), tool tip (40.73 oC), and the workpiece (40.03 oC); while soluble oil cutting fluid had a good surface finished of 0.8 mm, thus makes it more desirable cutting fluid in machining operation.

Role of Secondary Ions on the i-v Characteristics of Oxyfuel Flame Subject to an Electric Field

Abstract Recent use of ion currents as a sensing strategy in the mechanized oxyfuel cutting process motivated a series of studies which revealed that the steel work piece contributes secondary ions in addition to the primary ions classically identified in the oxyfuel flame. In this work, we present a computational model that has linked carbon-related chemi-ions as a source of secondary ions in preheating stage of oxyfuel cutting process subject to electric bias voltages. The flames' response to the electric field at different positive and negative polarities manifested a better understanding of the physical behavior of current-voltage (i-v) relationship. While copper surface exhibits stable and repeatable i-v characteristics, sporadically enhanced current was observed in positive saturation regime for steel surface, and this is believed to be due to the presence of secondary chemi-ions. To this extent, a source term of gaseous carbon has been assigned to mimic the ‘work surface’ reactions. The hypothesis is that since carbon is an important element, it will be diffusing out of the steel surface and evaporate into the flame.

Experimental Research on the Dynamic Stability of Internal Turning Tools for Long Overhangs

The roughness origin of machined surfaces is caused by the following physical causes: the copying of the shape and the roughness of the cutting part of the tool into the workpiece, the existence of vibration of the tool, and the existence of the build-up edge (BUE) on the cutting edge. The current work aims to analyze the vibration amplitude of tools. The roughness of the machined surfaces was observed on hardened steel workpieces. Internal turning technology was used, and we used several different boring bars (steel; carbide; tuned mass damper—TMD; impact damper—ID) and an internal turning operation using CBN inserts. We revealed the tool’s slenderness coefficient (TSC) values for stable cutting operations. For the steel holder, the value is TSC ≤ 4.25; for the carbide holder, the value is TSC ≤ 5.5; for the TMD holder, the value is 4.5 ≤ TSC ≤ 7.75; and for the ID holder, the value is TSC ≤ 8. The surface’s roughness was practically unchanged within the limits of stable machining. However, if the tools exceed the presented stable limits, vibration and roughness parameters deteriorate significantly; an example parameter (Ra) deteriorated from 0.350 μm to 1.832 μm.

PERBANDINGAN HASIL PEMBUBUTAN DENGAN MENGGUNAKAN MATA PAHAT KARBIDA DAN MATA PAHAT HSS DI BENGKEL POLMUH

In the fast-paced period, human desire to produce and compete quickly, efficiently and economically, became the basis for the development of tools and machine tools, the competition provided the main motivation in making machine tools that have accuracy, accuracy and precision, so as to make shape in accordance with the design (model). So in this case what should be considered is how to choose and determine the tool material to be used on a lathe, because it can affect the level of wear on the tool eye itself and the fineness or surface roughness that will be generated can be controlled visually. Comparing the use of carbide chisel with HSS chisel to eat ST 37 steel workpieces, in this study aims to determine the use of chisel blade in order to produce smooth workpiece surface fibers and have a small degree of roughness visually in the turning process of steel workpieces ST 37. The results of testing the use of carbide chisels produce finer surface fibers and visually smaller roughness than HSS chisels, so if you turn the ST 37 steel workpiece you should use carbide chisels to get good results.

Pengaruh Variasi Kedalaman Potong terhadap Gaya Potong dan Temperatur pada Proses Bubut Baja AISI 304 Berdasarkan Metode Elemen Hingga

Cutting forces are parameters that can be used to optimize the machining process, analyze power consumption, and affect temperature during the lathe process. Measurement of cutting forces using a dynamometer and temperature using a thermocouple is quite expensive. This article discusses the effect of machining parameters on cutting force and temperature on AISI 304 steel workpiece material with carbide insert tool. The method used to analyze cutting forces and temperatures is based on the finite element method (FEM). The results show that the cutting force fluctuates due to the influence of depth of cut. The greater the value of the depth of cut used, the greater the axial cutting force and tangential cutting force. While the temperature does not change due to variations in depth of cut. Cutting speed variations do not significantly affect the cutting force, but affect the cutting time and temperature. The greater the cutting speed value used, the greater the temperature produced and the less cutting time required.

Influence of Laser Modification of Nitride Ceramics Surface Layer on the Milling Cutters Reliability During the Finishing of Hardened Steel Workpieces

Influence of Laser Modification of Nitride Ceramics Surface Layer on the Milling Cutters Reliability During the Finishing of Hardened Steel Workpieces

Minimum roughness value in PMEDM with low-frequency vibration applied to workpiece

In powder-mixed electrical discharge machining (PMEDM), the application of low-frequency vibrations to a workpiece is considered beneficial to the machining quality. This study evaluates the average surface roughness (Ra) of SKD61 steel workpieces subjected to low-frequency vibrations during PMEDM using a Cu electrode and titanium powder. Specifically, Taguchi’s L25 experimental design method is used to evaluate the influence of the following process parameters: current, pulse-on time, concentration, push pressure, frequency, and amplitude. The analysis of variance technique is used to determine the minimum Ra (Ra[Formula: see text]) value. The results show that Ra is most and least strongly influenced by [Formula: see text] and [Formula: see text], respectively. Further, Ra[Formula: see text] is found to be 1.03 [Formula: see text]m.

A new hypothesis of steady-state flank wear progression of cutting tools with similar geometry and its verification

A new hypothesis is proposed and verified in this study to clarify the relationship between the progression and the mechanism of the flank wear of cutting tools in the steady-state region, assuming that the flank wear part expands while maintaining a geometrically similar profile. Based on Preston's law, the proposed hypothesis analytically leads to the conclusions that in the steady-state wear region where the cutting temperature is low and the abrasive wear is dominant, the flank wear width increases linearly, and the normal stress on the flank wear part does not change. Furthermore, this hypothesis suggests that the nonlinear and faster wear progression in the initial wear region is caused by an unsteady transition in the flank wear profile. Cutting experiments were conducted using tungsten carbide tools and carbon steel workpieces. The results demonstrated that the flank wear part expands with a certain similarity profile in the steady-state wear region. The normal stress distribution on the flank wear part was estimated from the similarity profile based on the proposed hypothesis, and the result was in rough agreement with that calculated by the finite element method in the literature.

High-quality surface polishing of selective-laser-melting stainless steel by defoamed magnetorheological elastomer

Thanks to the controllability of mechanical properties by the applied magnetic field, magnetorheological elastomer (MRE) polymers have demonstrated promising application prospects in high-quality surface polishing. To clarify the influence of the inner pores on the mechanical performance, four silicone rubber-based MRE polymers were manufactured by adding different contents of defoaming organosilicons. First, the surface and section microstructural features were observed on an ultra-deep microscope to evaluate the defoaming effect. Second, the energy storage modulus of the MRE polymers containing different contents of organosilicons was measured on a dynamic mechanical tensile device by changing the strength of the applied magnetic field. Third, the MRE polymers were fabricated into four MRE polishing pads and used for the surface polishing of selective-laser-melting 022Cr17Ni12Mo2 stainless steel workpieces on a DMG 5-axis machining center. Compared with the surface treated by the MRE pad without organosilicons, the surface quality of the workpiece polished by the MRE pad with 0.99 wt‰ organosilicons was improved by 45.4%, and the Ra reached 23.80 nm. The relationship between the energy storage modulus of the defoamed MRE polymers and their polishing capability was also discussed.

Optimization of jig boring process parameter by Taguchi approach

In present experimental work statistical process control is used to eliminate quality problems such as out of circularity of parts during jig boring operation. Taguchi parameter design technique deal with response from variable result from boring in Mild steel workpiece to estimating the optimum cutting conditions for minimum roundness error. To measure and get quick and accurate results the roundness error Coordinate Measuring Machine with latest software capabilities has been utilized. the characteristics relating to the cutting process, including feed rate, cutting speed, depth of cut, and tool material have been chosen as factors affecting roundness errors. The percentage contribution of significant components was assessed using ANOVA.

Parameters affecting the quality of friction drilled holes and formed thread in austenitic stainless steel AISI 304

The main purpose of this research paper is to improve the quality of the friction-drilled holes and formed thread by investigating the influence of the input working parameters that have not been investigated yet on the quality of the produced bores. Due to lack of research related to the hardness macro- and microstructure of formed threads, experiments were conducted to investigate these important issues. Finally, a tension test was performed to compare the performance of the form tapped thread with the conventionally cut thread. The experiments were conducted on difficult-to-cut material AISI 304 stainless steel workpieces with (2 and 3 mm) wall thicknesses. Tungsten carbide friction drills with diameters (Ø9.2, Ø7.3, and Ø4.5 mm) were used to perform the experiments. The effects of the ratio of workpiece thickness (t) to tool diameter (dT), rotational speed (N), and feed speed (f) on the hole diametral oversize (U), cylindricity error, and collar height were studied. The analysis of variance (ANOVA) showed that the t/d ratio was the most significant factor affecting the mean cylindricity error and the collar height. By comparing the performance of the three tools, it was noticeable that the friction drill Ø7.3 realized better results in terms of mean hole diametral oversize and mean cylindricity error. The elevated temperature associated with high plastic deformation during the processes resulting in fine grains with high hardness values were observed at the heat-affected zone. The longer effective thread length of the formed thread realized higher strength values than the cut thread.Graphical abstract

INVESTIGATION OF ELECTRIC DISHARGE MACHINING PARAMETERS TO MINIMIZE SURFACE ROUGHNESS

: Surface roughness during electrical discharge machining (EDM)was determined, inwhich material is removed by thermo-electric process due to the occurrence of successive dischargebetween workpiece and electrode. Box-Behnken design (BBD) involving four parameters dischargecurrent (I), Pulse ON time (PON), Pulse OFF time (POFF) andGap voltage, with three levels wasemployed to minimize the surface roughness. Other parameters such as Servo speed, Polarity and Dieelectric pressurewere kept constant throughout the machining. A copper electrode toolwas used to machine the holes in AISI 1045 steel work piece. Mathematical models were developed using Response Surface Methodology (RSM), while Analysis of variance (ANOVA) was used to observe individual effect, interaction between parameters, and to check validity of models. Results revealedthatpulse on time and discharge current were two main significant parameters that statistically affectedsurface roughness.

Design of Real-Time Extremum-Seeking Controller-Based Modelling for Optimizing MRR in Low Power EDM

Electric discharge machining (EDM) is one of the non-conventional machining processes that supports machining for high-strength and wear-resistant materials. It is a challenging task to select the process parameters in real-time to maximize the material removal rate since real-time process trials are expensive and the EDM process is stochastic. For the ease of finding process parameters, a modelling of the EDM process is proposed. Due to the non-linear relationship between the material removal rate (MRR) and discharge time, a model-free adaptive extremum-seeking controller (ESC) is proposed in the feedback path of the EDM process for finding an optimal value of the discharge time at which the maximum material removal rate can be achieved. The results of the model show a performance that is closer to the actual process by choosing steel workpieces and copper electrodes. The proposed model offers a lower error rate when compared with actual experimental process data. When compared to manual searching for an optimal point, extreme seeking online searching performed better as per the experimental results. It was observed that the experimental validation also proved that the ESC can produce a large MRR by tracking the extremum control. The present study has been limited to only the MRR, but it is also possible to implement such algorithms for more than one response parameter optimization in future studies. In such cases the performance measures of the process could be further enhanced, which could be used for a real-time complex die- and mold-making process using EDM.