Rockwell Hardness Tester Research Articles

Microstructure Characteristics and Mechanical Properties of Grey Cast Iron at Varied Ferrosilicon Addition

Inoculation is an essential metallurgical route for controlling solidification conditions of cast iron, consequently, in this study, the influence of varied percent ferrosilicon (FeSi) addition on microstructure and mechanical properties of grey cast iron (GCI) was investigated. A 50Kg capacity rotary furnace was used to melt the charge (Auto engine block scrap, graphite, ferrosilicon (FeSi) and limestone). The casting was produced in a greensand mold with wooden rectangular pattern of length 50 mm and breadth 30 mm. Chemical compositions and carbon equivalent values (CEVs) of the samples were determined, using Optical emission spectrometry (AR 4 metal analyzer) and the expression respectively. Microstructures of the samples were obtained, using metallurgical microscope (model number NJF-120A). The tensile and hardness properties were measured, using Universal tensile tester and Rockwell hardness tester respectively. From the results, C and Si were the major elements. Other trace elements were Mn, P, S and Al. CEVs of both the control and inoculated samples were less than 4.3%. Microstructure of the control sample was comprised of primary dendrites and graphite flakes, while those of the inoculated samples were characterized by varied amount of more developed primary dendrites, longer graphite flakes and austenite dendrites. Also, a number of small MnS particles were observed in relative amount within the microstructures. Tensile and hardness properties of the FeSi inoculated samples were superior to the control sample. Highest tensile strength and hardness values of 76.62 MPa and 99.89 HRB respectively were obtained at the optimum inoculation of 1.5 wt. % FeSi.

Effect of double quenching process on Microstructure and Properties of 20CrMoH Alloy Steel

Abstract This article investigates the influence of dual quenching process quenching temperature on the microstructure, hardness, and mechanical properties of 20CrMoH alloy steel through optical metallographic microscopy, Rockwell hardness tester, and universal mechanical testing machine. The results indicate that during the second quenching in the temperature range of 780-880 °C, with the increase of quenching temperature, the tensile strength of 20CrMoH steel shows a rapid increase trend, from 1250MPa to 1550MPa. At this time, the matrix structure gradually evolves from ferrite + bainite structure to bainite + martensite, which is also the main factor for its rapid increase in tensile strength; When the quenching temperature rises to above 850 °C, the influence of quenching temperature on the tensile strength decreases, and the tensile strength remains around 1550MPa. The secondary quenching temperature has little effect on the plasticity of the material. The overall reduction and elongation of the section under different quenching temperature conditions are at a similar level, with a reduction rate of 9% -12% and a stable reduction rate of 50% -60%, indicating good mechanical properties.

The influence of heat treatment on AlSi-polymer abradable coating

Abstract Abradable coatings, as one of the most important technologies for aero and industry gas turbine engines, have an extremely significant influence on engine performance. The macro-hardness of AlSi-Polyester for low-pressure compressor and as-sprayed coating degradation mechanism has been investigated by heat treatment process in imitation service condition. SEM (Scanning Electron Microscope) and OM (Optical Microscope) were used to observe the morphology of powder and coating microstructure in cross-section, respectively. Rockwell hardness tester was used to measure the macrohardness of coatings before and after heat treatment. It shows that AlSi-Polyester powder has an approximately spherical shape and uniform microstructure with alloy phase and polyester phase distribution in the coating prepared by air plasma spraying. Oxidation of the alloy phase and reduced polyester, as well as macrohardness in the as-sprayed coating, occur after the heat treatment process.

Fabrication of ramie/hemp fibers-reinforced hybrid polymer composite—A comprehensive study on biological and structural application

This study primarily investigates the antibacterial properties, tensile strength, flexural strength, impact strength, hardness, and microstructural characteristics of a composite, utilizing Scanning Electron Microscopy (SEM) for detailed analysis. The composite, crafted through a hand layup technique, optimally blends ramie and hemp fibers within an epoxy matrix. Its antibacterial efficacy was rigorously tested against common bacterial strains, demonstrating significant potential for medical and hygienic applications. The evaluation of tensile strength revealed the composite’s enhanced capability to withstand longitudinal stresses, with a peak strength of 37.81 MPa, achieved by increasing ramie fiber content. In addition, a flexural strength of 39.72 MPa underscored the material’s robust resistance to bending forces, crucial for structural uses. The composite’s impact strength, accessed via the Izod impact test, registered at 0.021 J/m2, indicating its ability to absorb and dissipate energy upon sudden impacts, making it ideal for automotive and protective gear applications. The Rockwell hardness test further quantified the composite’s resistance to surface indentation, vital for wear-resistant surfaces. SEM analysis offered a comprehensive view of the microstructural dynamics between the fibers and the matrix, especially under tensile stress, highlighting the intricacies of fiber–matrix adhesion, crack propagation, and overall composite integrity. Notably, the antibacterial properties were confirmed by an 18 mm inhibition zone, which showcases the composite’s ability to inhibit bacterial growth effectively.

Experimental Investigation of Hardness and Impact Variability in Wooden Agricultural Equipment

This study was conducted to determine the hardness testing and Impact testing of selected Timbers to be used in agricultural implements in Pantnagar, Udam Singh Nagar, between September 2015 and April 2016. The Rockwell hardness test is generally performed when quick and direct reading is desirable. The Rockwell hardness test was carried on the Digital Hardness testing machine on HRV-Scale. The impact strength of a material is determined with a Charpy or Izod impact test named after their inventors. the hardness of different types of timber, namely, Teak, Sal, Java plum, Eucalyptus, Yellow teak, North Indian Rose timber, red cedar, Mango, Margosa and Lebbeck was found to be 75.4, 79.1, 68.2, 69.1, 64.0, 87.1, 30.8, 63.2, 61.7 and 64.3 respectively. the Impact Strength of different types of timber, namely, Eucalyptus, Yellow teak, Teak, Lebbeck, Java plum, Mango, Red cedar, North Indian Rose timber, Margosa and Sal was found to be 49.2, 39.23, 56.71, 52.21, 46.3, 48.37, 49.2, 45.23, 41.6 and 58.89 KJ/m2 respectively. And their standard deviations were as follows: yellow teak (0.67), Red cedar (1.09), North Indian Rose timber (2.12), Teak (0.23), Lebbeck (7.95), Java plum (0.34), Eucalyptus (0.34), Margosa (0.71), Mango (0.87) and Sal (1.36) respectively. The timber of North Indian rose timber and Sal was found suitable for making Plankar, pulley and bearing block. The timber of North Indian rose timber, Sal and Eucalyptus was found best for making plough bottom.

Development and mechanical characterization of horse hair with titanium dioxide nanoparticles reinforced polyester composite

This study aims to examine the effects of waste material more especially horse hair as fiber on mechanical and physical properties. Tensile, flexural, impact, and hardness properties of horse hair fiber and titanium dioxide nanoparticles (TiO2 NPs) polyester composite were investigated to determine whether the latter might be used as a new material in various engineering applications for a longer life. To improve the impact resistance of the composite, horse hair fiber is mixed in different ratios with titanium dioxide and polyester as filler. Tensile, flexural, and impact mechanical properties were assessed using the Universal Testing Machine, the Rockwell Hardness Testing Machine, and the Izod Impact Test. Specimens were hand-put up using various fiber weight ratios. The results of this study showed that Specimen 5 showed a tremendous increase in flexural strength (98.87 MPa), tensile strength (91.46 MPa), hardness (115 HV), impact strength (15.98 J m−1), and water uptake (10.18%) as compared to the neat and also with the other Specimens. Scanning electron microscopy (SEM) was used to investigate the fracture surface in more detail in order to search for failure mechanisms and the dispersion of nanoparticles. SEM micrographs verified the uniform dispersion of the nanoparticles. Results suggest that these composites can be used as a material for a variety of applications, including biological claims that they are a practical, durable, and environmentally friendly choice.

Indentation Behavior Assessment of As-Built, Solution, and Artificial Aged Heat-Treated Selective Laser Melting Specimens of AlSi10Mg

This study was conducted to determine the indentation behavior of thin AlSi10Mg specimens manufactured using Selective Laser Melting (SLM) in the as-built condition along with two post-treatments, namely solution heat treatment and artificial aging. Four different thicknesses of 1 mm, 1.5 mm, 2 mm, and 2.5 mm of SLM specimens, with the different post-treatments, underwent standardized Rockwell hardness tests using a spherical indenter to determine their hardness values and assess the impression using a stereo microscope and scanning electron microscope (SEM). The as-built specimens showed a trend of smaller indentation depths with increasing specimen thickness, and finally creased with 0.1547 mm depth at 2.5 mm. However, the post-treatments altered the behavior of the specimens to a certain degree, giving larger experimental indentation depths of 0.2204 mm, 0.1962 mm, and 0.1798 mm at 1.0 mm, 1.5 mm, and 2.5 mm thickness, respectively, after solution heat treatment. Artificial aging showed a general decrease in indentation depth with increasing specimen thickness in contrast to solution treatment, and resulted in depths of 0.1888 mm and 0.1596 mm at 1.0 mm and 2.5 mm thickness. Furthermore, a material numerical model was made using stress–strain data on ANSYS Workbench to develop a predictive model for the indentation behavior of the specimens in contrast to experimentation. Under multi-linear isotropic hardening, the Finite Element Analysis (FEA) simulation produced indentation geometry with an average accuracy of 95.4% for the artificial aging series.

Noncontact hardness assessment of carbon steel with nonlinear Rayleigh waves induced by grating laser

Hardness is a crucial mechanical property to characterize the metal performance in service, and its nondestructive assessment is undoubtedly a challenging work. The objective of this paper is to realize a noncontact assessment of the heat-treated medium carbon steel by using grating laser-induced nonlinear Rayleigh waves. The generation and suppression mechanism of the instrument nonlinearity introduced by a grating laser source is explained theoretically. A different nonlinear parameter is adopted and its relevant feasibility is discussed. Ten heat-treated 45 steel samples underwent NDE using grating laser ultrasonics and the destructive testing using a Rockwell hardness tester in a successive manner. A logarithmic function is utilized to fit the correlation between the Rockwell A hardness and nonlinear parameter with a goodness of fit of 0.9102. The reasonableness of experimental fitting outcomes is discussed in the following, which confirms the potential application prospect.

Failure analysis and heat treatment process optimization of NOS525 rotary flat binaural hot forging die

A NOS525 steel rotary flat binaural hot forging die frequently failed too early due to collapse and wear in service. In this paper, the rotating planar binaural failure die was taken as the research object. Firstly, the sample design and sample processing of the failure die with different depths and directions were carried out. The material composition, hardness and metallographic structure of the samples were analyzed, and the tensile and impact properties were tested by direct-reading spectrometer, Rockwell hardness tester, optical microscope, scanning electron microscope, MTS testing machine and impact testing machine, etc. Meanwhile, with the help of Deform-HT software and JMatPro software, the coupling simulation of hardness, temperature and structure of the heat treatment of NOS525 steel was realized, and the hardness change of the material after heat treatment was predicted and verified by heat treatment test. The research results show that the composition of the die material is abnormal, especially the excessive P and C elements, at the same time, there is a phenomenon of quenching overheating and insufficient tempering, resulting in insufficient strength, toughness and hardness of the die material, in addition, the die surface is subjected to the cold and hot alternating load, and finally, the die surface collapses and wear too soon, resulting in its failure. Through the combination of heat treatment simulation optimization and test, the optimal heat treatment temperature of NOS525 steel was finally determined, that is, the quenching temperature of 1090℃, the first tempering temperature of 560℃, the second tempering temperature of 600℃, the third tempering temperature of 600℃, so that the mechanical properties of the material have been significantly improved.

Exploring tribological properties in the design and manufacturing of metal matrix composites: an investigation into the AL6061-SiC-fly ASH alloy fabricated via stir casting process

This study investigates a novel methodology to intricately craft a HAMMC and thoroughly examine its multifaceted mechanical and tribological characteristics. By combining silicon carbide (SiC) and fly ash as reinforcements, a unique identity is bestowed upon this hybrid composite, enhancing its structural integrity and functional attributes. Stir casting is the chosen methodology for fabricating this composite, favored for its economic viability and suitability for large-scale manufacturing. In this research, the emphasis is on developing a cost-effective composite that not only meets stringent economic considerations but also exhibits improved material properties. Within the realm of hybrid metal matrix composites, the well-regarded Al6061 takes on the role of the matrix material, while the synergistic inclusion of fly ash and SiC serves as reinforcing constituents. Three specimens with compostion 90% Al6061 + 5% SiC +5% Fly ash, 90% Al6061 + 10% SiC +6% Fly ash and 90% Al6061 + 15% SiC +7% Fly ash were fabricated. To unravel the intricacies of the fabricated Al6061 metal matrix composite, comprehensive tests are employed. These tests, including the Pin-on Disc test, Scratch test, Rockwell Hardness test, and Charpy Impact test, collectively work to unveil the nuanced tribological and mechanical behaviors encapsulated within this innovative alloy. The results indicated significant improvement in wear resistance in specimen comprising 78% Al6061 + 15% SiC +7% Fly Ash and volumetric loss found to have 0.96 g. Superior hardness characteristics and enhanced abrasion resistance found in 78% Al6061 + 15% SiC +7% Fly Ash than other two specimens. The highest impact strength exhibited in 90% Al 6,061 + 5% SiC +5% Fly ash specimen.

Understanding the corrosion and structural potential of 95Al-RHA-PSA composite for advance application

Material reinforcement has become popular in improving properties, such as corrosion, mechanical and wear behaviour. Aluminium-base composite has found usefulness in the technology of automobiles, aerospace, and marine and designs of a wide range of components. The use of reinforcement materials increases the efficiency of composites products and reduces overall expenses. Aluminium alloy composite provides low-cost advantages over many other matrix composites. The use of agro-based waste material as reinforcement alternatives is becoming very important because of its close to nothing cost and availability to produce nanoparticles. This study aim to use agro based processed rice hulls (RHA) and periwinkle shells (PSA) to improve aluminium properties in an attempt to gain prominence in today's automotive advancements. SEM imaging was conducted at a magnification of 15,000 at 20 kV to evaluate structural properties, while X-ray Diffractometer (XRD) images were utilized to observe the crystallography peaks and phases of the developed alloys. Rockwell hardness testing, in accordance with ASTM E18 standards, involved subjecting the samples to a 30 kg/f load for 30 s using a hardened steel ball for indentation. Corrosion properties were assessed via linear polarization resistance and open circuit potential measurements. From the results, there is a higher corrosion resistance from 95Al-RHA-PSA composite samples compared to the control (aluminium alloy) samples. The lower values of jcorr and higher values of Pr of the 95Al-RHA-PSA composite samples also indicated that the RHA and PSA content of the composite minimized the penetration of chloride ions into the active sites of the composite samples. The 95Al-2RHA-3PSA composite sample exhibited the lowest Cr of 1.4172 mm/year, lowest jcorr of 1.220E-04 A/cm2 and highest Pr of 70.02 Ω, which indicated the 95Al-2RHA-3PSA composite sample provided the most significant passivation, leading higher corrosion resistance. The XRD of the control sample has several crystallographic phases, with AlNi3Al2SiO8 exhibiting the most elevated peak intensity at about 550 a.u (2θ = 39°). In comparison, the peak intensity of the other crystals is less than 200 a.u. However, the 95Al-RHA-PSA composite samples exhibited crystallites of higher peak intensities and better morphological strengthening characteristics. The findings suggest promising prospects for the development of sustainable and long-lasting aluminium alloy for automotive use.

Development and characterization study of bagasse with stubble reinforced polyester hybrid composite

In the present day, recycling and reducing environmental pollution are the primary objectives of sustainable development. A lot of experts are considering the possibility of creating a new composite technology with waste materials. This work aims to investigate the effects of waste material on mechanical and hydrophobic properties, with a particular focus on bagasse fiber with stubble. The tensile, flexural, impact, and hardness properties of bagasse with stubble polyester composite were investigated to see if it may be used as a novel material in various engineering applications for a longer life. To improve the impact resistance of the composite, bagasse fibers is mixed in different ratios with polyester and stubble as infill. Additionally, a very tiny amount of TiO2 was added to every sample. Tensile, flexural, and impact mechanical properties were assessed using the Universal Testing Machine, the Rockwell Hardness Testing Machine, and the Izod Impact Test. Samples were hand-set out using varying weight ratios of binder, filler, and fiber. The study's findings demonstrated that the sample with a higher percentage of bagasse fiber demonstrated better mechanical and hydrophobic qualities as compared to the neat and other samples. It is an economical, long-lasting, and environmentally responsible option for a variety of applications.

Analysis and Characterization of Composites for their potential use in Disc Brake Pad

Brake pads are crucial for vehicle safety, converting kinetic energy to halt motion. They come in types like organic, semi-metallic, ceramic, and metallic. Beyond automotive, brake pads find application in industries such as aerospace, railways, manufacturing, and wind energy for controlled deceleration and safety. This study is primarily concerned with the quality and appropriateness of ceramic brake pads for automotive applications, which are an essential aspect of braking systems for vehicles. The performance characteristics of ceramic brake pads are well established, and this study explores the variables affecting their quality. Under high pressure, brake pad samples are prepared in the study using Powder Metallurgy (PM), which guarantees superior mechanical qualities by removing interface bonding problems. The samples are then sintered at 2850. Hardness, temperature resistance, wear resistance, and Electron Dispersive Spectroscopy (EDS) analysis are all included in the evaluation to ascertain the make-up and distribution of the materials in the brake pad. EDS sheds light on the degree of sintering and the presence of reinforcements. Heat resistance is evaluated using controlled thermal testing, while wear resistance and hardness are determined through Rockwell hardness testing and wear tests, respectively. These measurements are validated for use in automotive disc braking systems for vehicles and motorcycles. The findings are more reliable thanks to statistical analysis done with MINITAB. The study highlights research gaps in environmentally friendly materials, emerging technology impacts, and long-term brake pad durability.

Analysis of Selected Properties of Polymer Mixtures Derived from Virgin and Re-Granulated PP with Glass Fibers.

The problem of the growing amount of waste polymer materials currently affects virtually every area of the global economy. New actions taken by the E.U. and member states could lead to a reduction in the burden on the natural environment, as well as the reuse of thermoplastic waste. The aim of this study was to analyze the possibility of reusing post-industrial waste (recycled polypropylene-rPP) in order to produce mixtures with original polypropylene (PP) and glass fibers. The research undertaken is characterized by a high level of innovation and was carried out on an industrial scale from industrial waste. The primary goal of the analyses was to determine changes in the properties of the polymer mixtures depending on the amount of recycled polymers. For this purpose, four types of mixtures were prepared, characterized by different degrees of filling with recycled material obtained from big-bag packaging (the filling levels were 0 wt.%, 20 wt.%, 30 wt.%, and 70 wt.%). A detailed analysis of the physical properties of the obtained mixtures was carried out to determine changes in the densities depending on the amount of rPP material. In addition, changes in the MFIs (melt flow indexes), characterizing viscosity changes, were analyzed depending on the amount of secondary raw material used. An analysis of the mechanical properties was also carried out based on static tensile testing, the impact strength (the Charpy method), and the Rockwell hardness test (the M method). The analysis of the thermal changes was performed using the DSC method. The results showed that the composites made of virgin polypropylene (PP GF30) and those made from re-granulates and glass fibers (rPP GF30) are characterized by similar mechanical properties and significantly different processing properties, determined by MFI. This means that the addition of re-granulates significantly affects the processability of the obtained materials, while the addition of glass fibers maintains the basic mechanical properties.

Effect of Deformation Degree on Microstructure and Properties of Ni-Based Alloy Forgings

The primary objective of this paper is to investigate the influence of deformation degree on the microstructure and properties of a Ni-based superalloy. An upsetting experiment was conducted using a free-forging hammer to achieve a deformation degree ranging from 60% to 80%. The impact of the forging deformation degree on the hardness and high-temperature erosion performance was evaluated using the Rockwell hardness tester (HRC) and high-temperature erosion tester, respectively. The experimental results indicate that as the deformation degree increased, the hardness of the forged material progressively increased while the rate of high-temperature erosion gradually decreased. In order to comprehensively study the mechanism behind the variations in forging performance, optical microscopy (OM), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM) were employed. The findings reveal that as the deformation degree increased, the presence of small-angle grain boundaries and an increase in grain boundary area contributed to enhanced hardness in the alloy forgings. Furthermore, it was discovered that grain boundaries with twin orientation promoted dynamic recrystallization during deformation, specifically through a discontinuous dynamic recrystallization mechanism. Additionally, the precipitated γ′ phase in the alloy exhibited particle sizes ranging from 40 to 100 nm. This particle size range resulted in a higher critical shear stress value and a more pronounced strengthening effect on the alloy.

Failure analysis and numerical drive structure optimization design of Cr12Mo1V1 electrical connection die

A type of Cr12Mo1V1 electric connection die occured brittle fracture after 200 times of service, and its life was much lower than the design life of the die. In this paper, the 5M1E failure analysis method was adopted, combined with the characteristics of Cr12Mo1V1 cold-work die steel, scanning electron microscopy, direct reading spectrometer, Rockwell hardness tester, metallographic microscope and other means were used to analyze and test the macro fracture morphology, material composition, mechanical properties and microstructure of Cr12Mo1V1 electric connection die. The crimping process of the die was simulated by Deform software. The results show that the material composition is not up to standard, the strength is too low, the internal eutectic carbide is not uniform, the size of carbide exceeds the standard and so on are the root causes of the short life and brittle fracture of the die. In addition, the unreasonable designs of the crack slot and round hole of the die lead to excessive stress concentration in the crimping process of the die, which is too the main reason for the brittle fracture failure of the die. In view of the above factors, the paper puts forward some measures to prolong the life of the electric connection die from the aspects of raw materials, heat treatment, forging process and die structure design.

Investigation into Stress Relaxation and Creep Rate of C47200 Copper Alloy

Copper alloys have high thermal conductivity, relatively high mechanical strength, and toughness over a wide range of temperature; hence they are highly sorted for complex structural applications that required extreme heat flux under load. Creep of materials is classically associated with time-dependent plasticity under a constant stress/load at an elevated temperature, often greater than the absolute melting temperature. This research is aimed to study the evaluation of stress and creep rate in copper, identifying the mechanisms at which copper can easily be exposed to stress and creep deformations in structures. A 12 mm diameter copper rod with the composition of 52.05 % CuO and 30.26 % SnO2 was procured locally. Samples from the procured rod were heat treated to 650°C for 30 minutes and cooled in the still air as well as inside the furnace. Creep test was carried out at 760uC with a constant load corresponding to an initial stress (between 1.5 MPa and 350 MPa) and stress relation was carried out on a 98 kN capacity stress relaxation frame (from 350 MPa to 300 MPa). Rockwell hardness test and metallographic analysis (at 200 mm) were also conducted on the heat treated and unheated control samples. It was established that heat treatment reduced the hardness property of stress relaxed copper, accelerated the stress relaxation process up to 60 %, speed up both primary creep rate and the tertiary creep rate as well altered the linear creep pattern and behaviour.

Pemanfaatan Limbah Cangkang Kerang Simping (Amusium Pleuronectes) Sebagai Katalisator Pada Proses Carburizing

Simping clam’s a type of waste that is rarely used. The high levels of calcium carbonate in simping shells enable them to be used as a catalyst in the carburizing process. This research aimed to determine the effect of simping clam shell powder as a catalyst in the carburizing process on the hardness and impact strength values of ST 42 steel. This research used an experimental method by varying the percentage of simping clam shell powder: 0%, 10%, 20%, 30%, and coconut shell activated charcoal powder: 100%, 90%, 80%, and 70%, against ST 42 steel with variations in carburizing time: 3 hours, 6 hours, and 9 hours using a temperature of 900°C. The tests carried out were rockwell hardness tests and charpy impact tests according to ASTM E23 standards. From the test results, it was obtained that good hardness and impact strength values were obtained in 3 hours, the percentage was 30% with an average hardness value of 34.02 HRC and an impact value of 0.279 joules/mm2, in 6 hours the percentage was 30% with an average hardness value of 38. 92 HRC and an impact value of 0.229 joules/mm2, a time of 9 hours with a percentage of 30% an average hardness value of 43.68 HRC and an impact value of 0.179 joules/mm2. So by increasing the carburizing time, the hardness increases. The longer the carburizing time, the higher the percentage of simping clam shell powder used. This means that simping clam shell powder functions as a catalyst.

Analysis of the mechanical characteristics of mild steel using different heat treatment

The specimen used in this study to test various mechanical properties is mild steel. Analyzed are the effects of heat treatment (annealing, hardening, and tempering) on a particular specimen's mechanical characteristics. The most significant heat treatment procedures frequently employed to alter the mechanical properties of engineering materials are annealing, hardening, and tempering. Heat treatment is used to examine the mechanical characteristics of iron, which are typically ductility, hardness, yield strength, tensile strength, and impact resistance. Heat treatment increases mechanical qualities like tensile strength, yield strength, ductility, corrosion resistance, and creep rupture in addition to developing hardness and softness. These procedures also increase the effectiveness of the machining and increase their adaptability. Utilizing universal tensile testing equipment for the tensile test, a compression test, and a Rockwell hardness tester for the hardness test, the mechanical behavior of the samples is examined. Heat treating makes it simple to alter the mechanical properties to meet a specific design objective. To examine the impact of various tempering temperatures on the mechanical properties of mild steel, selected samples are heated to various temperatures above the austenitic area, quenched, and then tempered. Tensile strength variations are used to describe the changes in mechanical behavior compared to unquenched samples. Mild steel is used to create tensile test specimens, which are then heated through a variety of processes, including annealing, hardening, and tempering. The results demonstrated that different heat treatments for a specific application can alter and enhance the mechanical properties of mild steel.

Effect of Cryogenic Time on Wear Resistance of M2 High Speed Steel

The wear resistance, residual austenite volume and carbon content in martensite of M2 steel were studied by means of universal vertical friction and wear testing machine, X-ray diffractometer (XRD), scanning electron microscope (SEM) and digital Rockwell hardness tester. The results show that a large number of fine carbide particles in M2 steel martensite are precipitated by cryogenic treatment and distributed uniformly and diffusely in the structure. With the increase of cryogenic time, the residual Austenite volume of M2 steel gradually decreases, while the Martensite volume increases, resulting in the wear resistance and Rockwell hardness increasing first and then decreasing. After 24 hours of cryogenic treatment of M2 steel, its wear resistance increased by 310%, hardness increased by 3.6%. Therefore, 24 hours is confirmed as the best cryogenic treatment time for the wear resistance and hardness of M2 steel.