Rockwell Hardness Tester Research Articles

Pengaruh Jenis Limbah Aluminium Pada Proses Pengecoran Menggunakan Tungku Krusibel Terhadap Nilai Kekerasannya

Aluminum waste that has accumulated due to the widespread use of aluminum in household needs, daily life, and in the manufacture of industrial material components will have an impact on the environment if not handled properly. It is necessary to utilize aluminum waste in a product that has a sale value through a casting process using a crucible furnace. This research was conducted to determine the hardness differences of waste aluminum from used aluminum cans, used aluminum pots, and used aluminum wires melted in a smelting furnace. This study uses quantitative analysis and experimental research types. Tests carried out on this crucible furnace were carried out to determine the effect of the type of aluminum waste and the length of time it took to smelt the three types of material on the hardness results. The results of the Rockwell hardness test on aluminum can waste have an average value of 71.38 HRB, on aluminum pans waste it has an average value of 71.68 HRB, and on aluminum cable waste it has an average value of 53.02 HRB.

EFFECT OF QUENCHING MEDIA VARIATIONS ON THE HARDNESS AND MICROSTRUCTURES OF AISI O1 TOOL STEEL

Tool steels AISI O1 are widely used in the manufacturing industry to produce a wide variety of tools, moulds, and other applications requiring high wear resistance. Wear resistance is identic with high hardness, and the combination can be obtained by hardening-tempering and cryogenic treatment. However, cryogenic treatment requires liquid nitrogen, which is relatively expensive. Therefore, this study aims to determine whether to cool to produce high hardness, which is close to the hardness value of 69 HRC due to cryogenic treatment. The hardening process was carried out by heating the steel at a temperature of 880 °C and holding it for 30 minutes, then quenching using air, oil SAE 10, water with 15% salt, and ice water. The microstructure of the test sample was observed with an optical microscope, and the hardness was tested with a Rockwell hardness tester. The test results showed that the microstructure changed from pearlite and ferrite to bainite and martensite after hardening-quenching. The lower the quenching media temperature, the higher the hardness. Ice water quenching resulted in a fully martensitic structure, and the highest hardness was 66.37 HRC. Ice water is a quenching medium that can produce hardness almost close to the hardness of cryogenic treatment.

On the Use of Repeated Low-Temperature Nitrocementation for Effective Hardening of the Crankshafts of KAMAZ Vehicles, Ground to Repair Dimensions

Purpose of research the aim of the work is to develop an effective technology for surface hardening of the crankshafts of KAMAZ 740 engines, restored by re-grinding to repair dimensions, by means of their accelerated low-temperature nitrocementation in the conditions of car service (car repair) enterprises.Methods. Nitrocementation of the samples was carried out in a nitrogen-carbon paste. The samples with a nitrocementating coating were heated in a laboratory furnace with a vertical load of SSHOL-12-M3-U4. The nitrocemented samples were subjected to metallographic analysis using an Axio Observer.A1m optical microscope and a Quanta TM 3D200i electron scanning microscope. Phase analysis of diffusion layers on samples nitrocemented according to various modes was carried out on an XRD-7000S X-ray diffractometer. The microhardness of the nitrocemented samples was measured using a Duramin-5 microhardness meter with a computer and software. The hardness of the nitrocemented samples was measured on a TK-2M (Rockwell) hardness tester on the "A" scale according to the standard method.Results. The technology of low-temperature nitrocementation of nitrided crankshafts of KAMAZ vehicles after their repair by grinding with the removal of the hardened layer from the surfaces of the root and connecting rod necks is presented. It is shown that nitrocementation of 42HMFA steel, from which crankshafts are made, at a temperature of 520...580 °C for 3 hours in a highly active paste ensures the production of hardened layers in depth, structure, phase composition and hardness are almost identical to nitrided layers. Such nitrocementation can be a full-fledged and effective replacement for the re-nitriding of the restored shafts provided for in the technical documentation for the repair of KAMAZ engines, categories E-2, E-3 and E-4.Conclusion. The low labor intensity and technological simplicity of nitrocementation will allow it to be used to strengthen the crankshafts of all seven repair sizes provided for these parts, which can give a very large economic effect.

EFFECT OF QUENCHING HOLDING TIME ON MICROSTRUCTURE AND PROPERTIES OF HIGH SILICON HYPEREUTECTIC HIGH CHROMIUM CAST IRON

In this paper, the effects of different quenching holding times on the microstructure and properties of high-silicon hypereutectic high-chromium cast iron (Fe–4.0C–35.0Cr–1.9Si) were investigated. The effect of quenching holding time on the microstructure of high silicon hypereutectic high chromium cast iron was analyzed by optical microscope, scanning electron microscope and X-ray diffractometer. The hardness and wear resistance of high-silicon hypereutectic high-chromium cast iron quenched at 1150∘C for different time were tested by Rockwell hardness tester, microhardness tester and wear tester. The results show that the microstructure of as-cast high-silicon hypereutectic high-chromium cast iron is mainly composed of pearlite matrix and M7C3 carbide. Quenching heat treatment makes part of the matrix transform from pearlite to martensite, and precipitate a small amount of M[Formula: see text]C6 type secondary carbide. With the increase of quenching holding time from 1[Formula: see text]h to 6[Formula: see text]h, the amount of martensite transformation gradually increases, the primary carbide has no obvious change, the eutectic carbide tip dissolves, and the morphology gradually becomes smooth. The hardness and wear resistance both increase first and then decrease. After 4 hours of insulation, the hardness reaches the highest 60.5HRC, which is increased by 3 HRC compared to 1 hour of insulation. The wear resistance increases by 22.1% compared to 1 hour of insulation. At this time, the wear resistance is the best.

PROSES KARBURASI PADAT PADA BAJA KARBON RENDAH DENGAN TEMPERATUR 900 C, 1000 C, DAN 1100 C

This study aims to determine the effect of temperature on the solid carburizing on increasing the hardness value of ST37 steel. This solid carburizing uses temperature variations of 9000C, 10000C and 11000C, with a holding time of 30 minutes. The material used is a mixture of CaCO3 and coconut shell charcoal with mineral water as a cooling medium. The test carried out was the Rockwell hardness test which was carried out in the Mechanical Engineering Materials Testing Lab of Politeknik Negeri Ketapang. From the test results for ST37 steel, the average hardness obtained in the raw material = 48.3 HRB, then in each carbonation treatment at a temperature of 9000C = 48.6 HRB, a temperature of 10000C = 48.9 HRB, a temperature of 11000C = 49.1 HRB. Carburized steel plates with a temperature of 9000C, 10000C and 11000C the test results are harder than the raw material.

THE EFFECT OF QUENCHING TREATMENT BY VARIATION OF COOLING MEDIA (WATER, USED OIL, COOKING OIL) ON EGREK HARDNESS

Oil palm is harvested using the egrek agricultural implement. Using water for gilding, the blacksmith's egrek is toughened. The egrek that blacksmiths manufacture frequently is tarnished and worn out. Oil palm growers are consequently forced to swap them out for new ones.The product's economic value decreases as a result. Because of incorrect heat treatment, the cause of egrek is easily destroyed. The goal of this research was to ascertain how the heat treatment procedure affected how hard the quenched egrek was. Rockwell hardness test results. The hardness of the quenched egrek can be affected by changes in the water chilling medium, utilized oil, or cooking oil, according to statistical data processing using ANOVA and supported by the use of design expert software. Having an average carbon content of 0.379%, the raw material is made up of medium carbon steel. According to the results of the hardness test, the cooking oil cooling medium quenching process, which occurs at an average temperature of 800°C and a hardness value of 50.1 HRC, produces the average minimum hardness value, while the water cooling medium, which has an average hardness value of 60.4 HRC, produces the average maximum hardness value. The percentage contribution calculation reveals that used oil and cooking oil are the cooling media that have the greatest impact on the hardness level, with used oil contributing 96.37% and cooking oil contributing 96.61%, respectively, while water cooling media contribute 88.41%.

Microstructure and properties of carbon fiber-H62 brass matrix composites prepared by friction stir processing

Carbon fibre (CF) reinforced H62 brass matrix composites were fabricated by friction stir process (FSP). The influence of CF compound amount and welding speed on the microstructure and properties of CF-H62 brass matrix composites was investigated by variable orthogonal experiments by drilling CF filled holes in H62 brass plates. Under the set experimental process parameters, the stirred friction processed composites with good surface formation, all without macroscopic defects, no loosening or holes. Optical microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the microstructure of the joints. The microstructure is a fine isometric crystal that is the result of dynamic recrystallisation. As the welding speed increased from 20 mm/min to 60 mm/min, the average grain size at the weld in the weld zone decreased from 5 μm to 2 μm. When the hole depth of the filled CF was 1.5 mm and the welding speed was 40 mm/min, the CF was most uniformly distributed in the composite area. This paper uses the orthogonal test method to optimise the formulation design of a variety of reinforcement fibre contents. The friction and wear properties as well as the physical properties of the two friction material samples were tested using a constant speed friction tester, a shear strength tester and a Rockwell hardness tester. The influence of each fibre and content on the friction material properties was investigated by extreme difference analysis; The best fibre ratio formulation was selected by combining a fuzzy comprehensive evaluation method. ANOVA was used to investigate the changes in friction material properties after the addition of graphene.

A proposed method using t-test for stability check in proficiency testing in tensile and hardness tests

The proficiency testing is very powerful tool for laboratories to continuously monitor the validity of the results, and is considered one of the technical requirements for accreditation according to ISO 17025. Stability check for the test samples or artifacts is important to ensure that these samples are fit for purpose, and give consistent performance over a specified period of time. The aim of this work is to propose a method for stability check using t-test as an alternative method of that followed in ISO 13528. The proposed t-test method is applied on proficiency test for Rockwell hardness test, Brinell hardness test, and tensile test for both PVC (Polyvinyl Chloride), and steel reinforcement bars. The results for stability check are analyzed, and compared with the results obtained from the convenient method of ISO 13528. The proposed method excelled the convenient method followed by ISO 13528. The main advantage of the proposed method using t- test is independent on the participants’ results, it depends only on the results from one lab , which perform the stability check.

Hardness assessment of novel waste tire rubber-polypropylene composite

As the manufacturing and use of vehicles are increasing globally, the disposal and recycling of waste tire have become a major environmental issue when they are out of service life. One of the potential recycling processes is to turn the waste tire into a useful composite material that may have domestic and industrial applications where hard materials are required. In the present study, hardness of novel Waste Tire Rubber-Polypropylene (WTR-PP) composite is evaluated using analog Rockwell hardness tester. Since WTR is a soft material and elastic in nature, the addition of WTR in composite materials affects the properties of the resulting novel WTR-PP composite including the hardness. It is observed from the test that the hardness of the WTR-PP composites decreases with the increase of WTR % due to lower hardness of WTR as compared to PP. Results reveal that upon addition of 20%, 40%, 60% and 80% WTR in the composite the hardness of composite decreased by 42.5%, 61.8%, 84.09% and 93.18% respectively.

Influence of silver addition on wear characteristics of Cu-Al-Mn shape memory alloys

The aim of the present work is to study wear resistance and hardness of Cu-Al-Mn shape memory alloys prepared by the addition of Silver(Ag) as alloying element. Cu-Al-Mn-Ag shape memory alloys are prepared by varying the Ag concentration of 2%, 4% & 6% (wt.%). Wear behavior of alloys are investigated by using a Pin on disc tribometer at room temperature under dry sliding conditions by considering three parameters i.e. applied load, sliding speed and sliding distance. Hardness measurement is recorded by Rockwell hardness testing equipment. From the experimental findings it is observed that the amount of silver added in the alloys has shown significant effect in the improvement of wear resistance and hardness of prepared alloys. As the pin on disc speed increased, wear was reduced by 55%. A reduction in wear of 42% was observed with an increase in the volume fraction of silver.

Analysis of the influence of temperature and hold time in the solid carburization process on the hardness and microstructure of AISI 1020 and 1045 using Oil Cooling

This study aims to determine the effect of variations in temperature and holding time on the value of hardness and microstructure in the carburizing process of low-carbon steel and medium-carbon steel. The temperature variations used during the carburizing process were 850oC and 950oC with variations of the holding time used being 15 minutes and 30 minutes. The types of materials used are AISI 1020 steel and AISI 1045 steel. In the carburizing process, the carbon source used is wood charcoal powder. After the process of adding carbon elements, the material will be quenched in the oil medium. The tests carried out were hardness testing and microstructure observations. The hardness test used the B-scale Rockwell hardness test method. The surface etching process of the material used a nital etching solution, namely a mixture of 3% nitric acid (HNO3) and 97% ethanol. The results showed that the lowest increase in hardness occurred at 850oC with a holding time of 15 minutes, namely 82.00 HRB for AISI 1020 steel and 95.66 HRB for AISI 1045 steel. Meanwhile, the highest increase in hardness occurred at a temperature of 950oC with a holding time of 30 minutes. namely 93.00 HRB on AISI 1020 steel and 105.33 HRB on AISI 1045 steel. This shows that the higher the temperature and the longer the holding time, the higher the hardness value.

Numerical and Experimental Investigations of Cold-Sprayed Basalt Fiber-Reinforced Metal Matrix Composite Coating.

The aluminum-basalt fiber composite coating was prepared for the first time with basalt fiber as the spraying material by cold-spraying technology. Hybrid deposition behavior was studied by numerical simulation based on Fluent and ABAQUS. The microstructure of the composite coating was observed on the as-sprayed, cross-sectional, and fracture surfaces by SEM, focusing on the deposited morphology of the reinforcing phase basalt fibers in the coating, the distribution of basalt fibers, and the interaction between basalt fibers and metallic aluminum. The results show that there are four main morphologies of the basalt fiber-reinforced phase, i.e., transverse cracking, brittle fracture, deformation, and bending in the coating. At the same time, there are two modes of contact between aluminum and basalt fibers. Firstly, the thermally softened aluminum envelops the basalt fibers, forming a seamless connection. Secondly, the aluminum that has not undergone the softening effect creates a closed space, with the basalt fibers securely trapped within it. Moreover, the Rockwell hardness test and the friction-wear test were conducted on Al-basalt fiber composite coating, and the results showed that the composite coating has high wear resistance and high hardness.

Fabrication and Characterization of Eco-Friendly Natural Human Hair Fiber Reinforced Polyester Composite

ABSTRACT In the present era, recycling and reducing environmental pollution are the main objectives of sustainable development. Many researchers are thinking of innovation in the field of composite technology by utilizing waste material. The objective of this work is to check the effect of a human hair (waste material) as fiber on physical and mechanical properties. Tensile, flexural, impact strengths and hardness of human hair based polyester composite were evaluated to assess the possibility of using it as a new material in various engineering applications for longer life. The addition of polyester to the human hair fiber with marble dust adds as filler to increase the Impact strength of fabricated composite. Samples are fabricated by the hand lay-up process (40: 20: 40 matrix, filler and fiber ratio by weight), and the mechanical properties like tensile, flexural, impact using the Universal Testing Machine, Hardness test using Rockwell hardness testing machine, Impact using Izod impact test were all evaluated. It is an eco-friendly, long life and cost effective solution for various applications.

MECHANICAL STUDY OF 9Cr-316SS-1Mo MATERIALS FOR NUCLEAR FUEL CLADDING MATERIALS POWER REACTORS

Cladding or cladding used for nuclear fuel elements requires special requirements such as good mechanical properties, radiation resistance, corrosion resistance, adequate physical and chemical properties, and low thermal neutron absorption. Materials that are widely used as structural materials for nuclear reactors are beryllium, magnesium, aluminum, zirconium and their alloys. Alloy 9Cr-316-1Mo as Nuclear fuel cladding material. 9Cr-316-1Mo material has been made. The material 9Cr-316-1Mo was chosen as an alternative cladding material because it has good mechanical and chemical properties with a microscopic cross-section of 2.6 barn. At first, the 9Cr-316-1Mo sample was cast withThe composition is 90% 316L Stainless Steel, 9% Chromium (Cr) and 1% Molybdenum (Mo) is added using an electric arc. After casting the alloy,the composition of 9Cr-316-1Mo was tested without heating and then given heat treatment (tempering) starting from 100 0C, 200 0C, 300 0C, 400 0C and 500 0C and allowed to stand for 60 minutes, then tested for hardness (rockwell) , Impact testing, micro structure testing and Chemical composition testing (XRF). The results of the Rockwell hardness test obtained the highest hardness value in the sample without tempering, namely 20.66 HRc and the lowest hardness value in the sample with tempering 500 0C, namely 16.33 HRc. Then the impact test results obtained the highest impact energy value in the sample with tempering 100 0C, which is 0.9996 Joule/mm2 and the lowest impact energy value in the sample with tempering 500 0C, which is 0.9962 Joule/mm2. The results of the microstructure test showed that the structure of 9Cr-316-1Mo still contained ferrite, pearlite and martensite. The testing process is still not fully completed and will be reported later.

A proposed method using t-test for stability check in proficiency testing in tensile and hardness tests

Proficiency testing is a very powerful tool for laboratories to continuously monitor the validity of the results, and is considered one of the technical requirements for accreditation according to ISO 17025. Stability check for the test samples or artefacts is important to ensure that these samples are fit for purpose, and give consistent performance over a specified period of time. The aim of this work is to propose a method for stability check using t-test as an alternative method of that followed in ISO 13528. The proposed t-test method is applied on proficiency test for Rockwell hardness test, Brinell hardness test, and tensile test for both PVC (Polyvinyl Chloride), and steel reinforcement bars. The results of stability check are analyzed, and compared with the results obtained from the convenient method of ISO 13528. The proposed method excelled the convenient method followed by ISO 13528. The main advantage of the proposed method using the t-test is that it is independent of the participants’ results; it depends only on the results from the lab, which performs the stability check

Ceramic Oxide MgO-SiO2-Al2O3 as Capacitor

This study aims to analyze the effect of the composition MgO-SiO2-AL2O3 on dielectric constant, hardness, and microstructure. Good ceramics can be produced from an alloy of ceramic materials with a certain composition that is hard and able to store electric charge. Magnesium Oxide (MgO) ranked as the most heat-resistant insulating material for application practice. Silica (SiO2) is known for its hardness, besides that silica can also reduce plasticity and reduce dry shrinkage. The addition of alumina (AL2O3) to the ceramic resulted in a reduction in the mass of the ceramic. However, the hardness value obtained is increasing. So that the alloy between MgO-SiO2-AL2O3 is expected to produce ceramics that have superior mechanical and electrical properties. This study varied the composition of MgO-SiO2-AL2O3 with a composition ratio of 50%:50%:0%, 80%:15%:5%, 60%:32%:8%, 30%:63%,12%, 10%:75%:15%. Sintering was carried out at 12000C with a holding time of 8 hours. Then the sample's capacitance was measured using a capacitance meter and calculated the value of the dielectric constant, and hardness test using the Rockwell Hardness Tester type. The samples that have been tested for hardness are then taken three hardness values, namely low, medium, and high hardness to be tested for microstructure by SEM. The results show the MgO content increases, the value of the dielectric constant will increase but cause more pores. The level of SiO2-AL2O3 increases the higher the hardness value and the smaller the number of pores. Of the 5 samples that have been studied, the best sample used is sample 3 which has a good dielectric constant value, moderate hardness value, and the microstructure of the number of pores is not too much

Parameters optimization of tungsten inert gas welding process on 304L stainless steel using grey based Taguchi method

Tungsten inert gas can be used to weld stainless steel due to its offering sound weld, narrow fusion zone, precise control weld’s shape and over penetration, spatter free, slagless, stable arc and low electrode wear. The goal of this study was to offer the best process parameters for improving the mechanical characteristics of the weld joint. The experimental analysis approach was applied in this work, and the experiment was carried out on 304L stainless steel using L16. The selected welding parameters were welding travel speed, current of welding, gas flow rate, arc length, and root gap. Rockwell hardness, tensile strength, and bending strength tests were the examined mechanical properties on the weld joint. Based on the grey based Taguchi method, the optimal level-settings of welding travel speed, current of welding, flow rate of gas, arc length, and root gap were obtained 2.7 mm s−1, 160 A, 14 l min−1, 3 mm, and 1 mm, respectively. The analysis result of ANOVA showed that the current has the greatest impact and it was followed by travel speed and root gap on weld joint quality with percentage contribution of 80.77%, 10.86%, and 5.98%, respectively. According to confirmation results, the average grey relational grade of 0.863 which was found between the confidence interval of 0.800 to 1.082 for the 95% confidence level, and the maximum Rockwell hardness, tensile strength and bending strength were obtained 101.38 HRB, 1425.8 MPa and 1648.6 MPa, respectively.

Low temperature heat treatment of steel and the effect of quenching on the strength and oxidation behaviour

Mild steel is widely used in the engineering field because of its low carbon content that is often ductile and machinable. However, mild steel despite its hardness properties when exposed to corrosion mediums easily corrodes. This study investigates the effect of mild steel quenching after different heat treatment procedures and later exposed to corrosion environment (sodium chloride solution) to observe the corrosion behaviour of the metal. The mild steel samples were cut into dimensions of 75 mm x 25 mm x 4.5 mm and heat treated at temperatures of 100 ° C, 300 ° C, and 500 ° C, and quenched in both water and oil mediums. The temperature applied to the mild steel is expected to produce a phase structure in the pearlite region, and thereby improving its properties. The quenching medium influenced the microstructure of the mild steel, the hardness values as well as the corrosion resistant capabilities of the metal. The mechanical properties were tested using ultimate testing machine and Rockwell hardness Tester. Data obtained from this research, shows that the samples heat treated, water, and oil quenched all showed improved properties. It was observed that the percentage elongation for oil quenched at 100 °C, 300 °C, and 500 °C is 18.5 %, 14.1 %, and 12.4 % which is higher than water quenched which recorded 16.7 %, 12.3 %, and 9.8 % but the reverse was the results obtained for the other mechanical properties. The optical microscopy was used to observe surface morphology when the surface is exposed to the corrosion medium. It was observed that the oil quenched samples experience the lowest weight loss when compared to water quenched samples, and the as received sample had the highest weight loss. This shows that heat treatment and quenching provides some form of protection for the mild steel samples.

Study on the Influence of Silicon and Aluminum on the Microstructure and Properties of Low Cobalt M42 High-Speed Steel

M42 HSS (W2Mo9Cr4VCo8 ) is widely used as a high cobalt super-hard high-speed steel (HSS) for various cutting tool materials, but high cobalt HSS does not bring good economic benefits. In this paper, the effects of Si and Al on the organization and mechanical properties of low cobalt M42 HSS were investigated. The microstructure of HSS was analyzed by OM, SEM, EDS, XRD, etc. Rockwell hardness test, impact toughness test and flexural strength test were conducted. The results of the study showed that only increasing the Si content in M42 HSS containing 4.0% Co did not significantly improve the material organization and properties, and caused a sharp deterioration in impact toughness. After adding 1.0% Si and 1.0% Al to M42 HSS containing 4.0% Co, Si and Al can partially replace Co, resulting in a more uniform and diffuse carbide distribution. The hardness of the material is increased to 68.3 HRC and the impact toughness is increased to 13.8 Jꞏcm-2, which has better overall mechanical properties and can meet the processing and cutting requirements under actual working conditions.

THE EFFECT OF HEAT TREATMENT ON HARDNESS AND MICROSTRUCTURE OF MILD STEEL

Mild steel is the most preferred material for domestic and light-load structural applications. Such widely used mild steel materials is considered here to study their response to heat treatment in terms of hardness and microstructure. The heat treatment is done to an annealing temperature (750oC) with the muffle furnace and then quenched the samples after a fixed incubation period in the furnace say 0.5, 1, 1.5 hr. The hardness and the microstructure of the heat-treated samples are evaluated using the Rockwell Hardness test and a metallurgical microscope. It was observed that heat treatment has contributed to changes in the hardness and microstructure