Carburizing Process Research Articles

Pengaruh Variasi Jenis Katalisator Dan Holding Time Pada Proses Pack Carburizing Terhadap Perubahan Komposisi Karbon Dan Nilai Kekerasan Baja Karbon Rendah (Low Carbon Steel) St 37

In this study, a pack carburizing process was carried out on low carbon steel using activated carbon, coconut shell charcoal and various catalysts in the form of ale-ale shells, eggshells, and beef bones. The method used is heating at an austenite temperature of 900 oC with a variation of holding time of 30, 60, and 90 minutes, then quenching using water, followed by hardness testing with the Vickers method and composition testing. The general result is that the three types of catalysts can accelerate the diffusion-reaction so that the carbon addition process occurs and the longer holding time can provide an opportunity for the carbon formed to transform from the pearlite microstructure to the austenite microstructure, and when quenching it forms the Martensite microstructure. Of the three types of catalysts that produced the highest hardness was an ale-ale shell, from the initial hardness 119 HV to 464 HV.

Characterization of Graded Subsurface Zones in Industrial Case-Hardening Using a Non-Destructive Testing System

Abstract For process monitoring and quality assurance of case-hardened components, the determination of the case-hardening depth in the manufacturing process after hardening of the subsurface layer is a quality verification that is often required in industry. Currently, these quality assurance tests can only be realized with destructive measures. During case-hardening, the essential microstructural formation, and thus the key component properties are developed during the heat treatment in the cooling section. The testing technique used in the present study is based on the analysis of harmonic signals of eddy current testing. The aim of this project was to achieve an early identification of incorrect cooling processes in the case of a known transformation behaviour of the components during cooling. The data collected in the industrial hardening process show that an evaluation of the carburizing process on the basis of the case-hardening depth can be carried out non-destructively during component cooling and in the cooled state with the use of eddy current technology.

Analysis and Predicting the Energy Consumption of Low-Pressure Carburising Processes

The monitoring of the performance of heat treatment equipment has been the subject of a number of studies. This paper proposes and explores a new study on the models—and the monitoring thereof—for predicting the energy intensity of low-pressure carburisation processes using the DeepCaseMaster Evolution soaking furnace. For research purposes, 18 carburising experiments were performed with different carbon layers, at different input parameters, such as the number of cycles, time, temperature and average carburising pressure. Based on the research experiments conducted and statistical analysis, the influence of individual parameters on the energy consumption of the pump and heating systems was determined. Moreover, the models were verified on real data of low-pressure carburising processes. The innovativeness of the proposed solution is a combination of two areas: (1) defining and measurement of the parameters of the low-pressure carburising process; and (2) predicting the energy consumption of low-pressure carburising processes using correlation and regression analyses. The possibilities of using the results of this research in practice are demonstrated convincingly.

Optimizing the carburization conditions of supported rhenium carbide for guaiacol conversion

The present work evaluates the effect of ethylene content of a carburization mixture on the formation of carburized rhenium supported on activated carbon. The resulting catalysts were characterized by N2 physisorption, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and temperature-programmed reduction, and the results show a strong effect on the final phase obtained. A high amount of ethylene inhibited the carburization process, resulting in carbon formation, while a lower amount (≤ 35 %) of ethylene was favorable to the formation of the carbide phase. The catalysts were evaluated for the hydrodeoxygenation (HDO) of guaiacol, a bio-oil model compound, and a high yield of benzene (50 %), a desirable aromatic compound, was obtained at complete conversion over the catalysts containing the carbide phase.

Prediction of the formation of carbide network on grain boundaries in carburizing of 18CrNiMo7-6 steel alloys

With the increasing surface carbon content during the carburizing process, undesirable carbide networks are generally formed on the surface and in the near-surface region of the mechanical parts composed of plain low carbon steels. Therefore, it is of great significance to predict the formation conditions of carbide networks in advance and thereby avoid their appearance. The effect of carbon concentration and grain size on the formation of carbide networks of 18CrNiMo7-6 steel alloys has been investigated in this work. The results show that the network carbide of the 18CrNiMo7-6 steel alloys after carburizing was mainly composed of cementite. Grain size has a significant effect on the formation of carbide network for 18CrNiMo7-6 steels during carburizing due to the preferential diffusion of excess carbon through the grain boundaries. Grain growth behavior of the 18CrNiMo7-6 steels during different pseudo-carburizing process was investigated to build the relationship between grain size and process parameters of time and temperature. On the other hand, a mathematical model including variables of process time and temperature was established to predict the critical volume fraction of carbides forming networks by estimating the grain size of the 18CrNiMo7-6 steel alloys in the carburizing process. And the critical carbon concentration for forming carbide networks could be further calculated through the thermodynamic simulation. The results indicate that carbide network could be restrained by adjusting the process parameters of temperature, time and carbon concentration before carburizing with reasonable accuracy.

The comparison pack carburizing-nitriding SUS 316 with gas type Welding Grade and Ultra High Purity

The paper discusses the comparison of pack carburizing-nitriding SUS 316 with gas Nitrogen. The purpose of this study was to increase the hardness and corrosion resistance of SUS 316.
 The research used a pack carburizing-nitriding method with gas type Welding Grade (WG) and Ultra High Purity (UHP). The pack carburizing process uses teak wood activated carbon and barium carbonate as a bio-photo catalyst. The specimens were put into a Sealed Steel Container containing teak wood activated carbon, with a depth of 1 cm below the activated carbon's surface. The test material is then heated until it reaches 850 °C and is held for 1 hour in a heating furnace. Furthermore, the nitriding process, the specimen is put into a tightly closed nitrogen tube, then nitrogen gas flows until the pressure reaches 41 bar and is held for 24 hours. They are using Welding Grade (WG) and Ultra High Purity (UHP) gas types. Furthermore, microVickers hardness testing, optical microscope, and Scan Electron Microscope (SEM) were carried out.
 The results of the study include a. There was an increase in violence by 41.7 % for UHP and WG (17.3 %). b. The formation of nitride compounds and carbon dissipation on the specimen surface in the UHP carburizing-nitriding pack treatment is more than WG. The formation of a nitride layer is indicated by its fine and dense morphology and film bonding to the substrate. The chemical composition affects the diffusivity of nitrogen atoms in modifying the surface layer of the substrate. The higher the nitride compound formed, the smoother the substrate surface. Also, with UHP treatment, the lower the elemental content of Cr makes SUS 316 more resistant to corrosion. So that SUS 316 UHP can be recommended for use as an implant material

Investigation of the Effects of Low‐Pressure Carburizing Process Parameters on Microstructural Evolution by Means of In Situ Synchrotron X‐Ray Diffraction

In situ X‐ray diffraction experiments during low‐pressure carburizing processes are performed at the German Electron Synchrotron Facility, Beamline P07, in Hamburg, Germany, with a specially developed process chamber. Microstructural evolution is precisely analyzed based on diffraction data, and several process parameters are varied. The investigations focus on boost and diffusion steps in which carbon donor gas interacts with the hot steel surface and carbon atoms diffuse through the sample. An increased process temperature leads to higher carbon absorption during the boost step, especially at the early stages of the process. Regardless of process parameters, austenite saturation is reached in a few seconds. Therefore, longer boost step duration and/or a higher acetylene amount does not directly increase the carbon profile; instead, this would only increase the amount of carbides formed on the surface, which would contribute to the carbon profile by dissolution in the following steps. Therefore, shorter and a high number of boost steps are recommended for high efficiency. The cementite formation rate shows a similar trend with austenite saturation. It is very fast at the beginning and then stays almost constant. Therefore, introducing acetylene to the furnace after that point has no positive effect on the carburization.

The Hybrid Process of Low-Pressure Carburizing and Metallization (Cr + LPC, Al + LPC) of 17CrNiMo7-6 and 10NiCrMo13-5 Steels

This paper presents the concept of modification of physicochemical properties of steels by simultaneous diffusion saturation with carbon and chromium or aluminum. The application of a hybrid surface treatment process consisting of a combination of aluminizing and low-pressure carburizing (Al + LPC) resulted in a reduction in the amount of retained austenite in the surface layer of the steel. While the use of chromium plating and low-pressure carburizing (Cr + LPC) induced an improvement in the corrosion resistance of the carburized steels. It is of particular importance in case of vacuum processes after the application of which the active surface corrodes easily, as well as in case of carburizing of low-alloy steel with nickel, where an increased content of retained austenite in the surface layer is found after carburizing.

ANALISA PENGUATAN MATA PISAU MESIN PENCACAH SAMPAH ORGANIK DENGAN PROSES HEAT TREATMENT BERTINGKAT

Garbage has been considered useless and disgusting. The problem of pollution due to the presence of waste requires processing and management to overcome it, one of which is composting. The waste chopper is a tool that makes it easy to destroy and speed up the composting process of organic waste. The progress of the industrial sector cannot be separated from the development of the tool industry or blacksmiths, both large and small. In the manufacture of blades or blacksmith himself experienced several problems, among many consumers who complains of sharpness and strength of the blades are manufactured. There are several factors that affect the sharpness and strength of the blades, including during the heat treatment process. This study used an experimental method with ST 41 steel as the material. Carburizing process using coconut shell charcoal powder at a temperature of 875 ℃, hardness test and wear test material and the salt water quenching media. The highest average hardness test value was produced by the carburising and hardening processes with a hardness value of 599.7 VHN, while the lowest wear test value was found in the carburising and hardening process, namely 0,0000767 mm³ / kg.m.

Pressure effect on diffusion of carbon at the 85.91∘〈100〉 symmetric tilt grain boundary of α -iron

The diffusion mechanism of carbon in iron plays a vital role in carburization processes, steel fabrication, and metal dusting corrosion. In this paper, using the kinetic activation-relaxation technique (k-ART), an off-lattice kinetic Monte Carlo algorithm with on-the-fly catalog building that allows to obtain diffusion properties over large time scales taking full account of chemical and elastic effects coupled with an EAM potential, we investigate the effect of pressure on the diffusion properties of carbon in $85.{91}^{\ensuremath{\circ}}\phantom{\rule{4pt}{0ex}}\ensuremath{\langle}100\ensuremath{\rangle}$ symmetric tilt grain boundaries (GB) of $\ensuremath{\alpha}$-iron up to a pressure of 12 kbar at a single temperature of 600 K. We find that, while the effect of pressure can strongly modify the C stability and diffusivity in the GB in ways that depend closely on the local environment and the nature of the deformation, isotropic and uniaxial pressure can lead to opposite and nonmonotonous effects regarding segregation energy and activation barriers. These observations are relevant to understanding of the evolution of heterogeneous materials, where variations of local pressure can alter the carbon diffusion across the material.

Investigation of the Microstructural Evolution during Hot Stamping of a Carburized Complex Phase Steel by Laser-Ultrasonics.

Prior carburization of semi-finished steel sheets is a new process variant in hot stamping to manufacture parts with tailored properties. Compared to conventional hot stamping processes, a complex phase typed steel alloy is used instead of 22MnB5. Yet recent investigations focused on final mechanical properties rather than microstructural mechanisms cause an increase in strength. Thus, the influence of additional carburization on the microstructural evolution during hot stamping of a complex phase steel CP-W®800 is investigated within this work. The phase transformation behavior, as well as the grain growth during austenitization, is evaluated by in-situ measurements employing a laser-ultrasound sensor. The results are correlated with additional hardness measurements in as-quenched condition and supplementary micrographs. The experiments reveal that the carburization process significantly improves the hardenability of the CP-W®800. However, even at quenching rates of 70 K/s no fully martensitic microstructure was achievable. Still, the resulting hardness of the carburized samples might exceed the fully martensitic hardness of 22MnB5 derived from literature. Furthermore, the carburization process has no adverse effect on the fine grain stability of the complex phase steel. This makes it more robust in terms of grain size than the conventional hot stamping steel 22MnB5.

Structure-controlled tungsten carbide nanoplates for enhanced hydrogen evolution reaction

Developing a low-cost and durable non-noble metal eletrocatalyst for hydrogen evolution reaction (HER) is critical in efficient hydrogen production. Herein, tungsten carbide nanoplates (WC NPs) with typical mesoporous structure were prepared by a controlled hydrothermal reaction followed by a gas-solid carburization process. The crystal phases, microstructure and chemical components of the nanoplates were characterized, and their electrochemical properties were measured. The results show that the as-prepared WC NPs expose active sites upmost, and exhibit enhanced conductivity and superior HER performance in acid solution in terms of a small η 10 (overpotential to obtain a current density of 10 mA cm−2) of 120 mV, a Tafel slope of 58 mV dec−1 and outstanding long-term cycling stability. These indicate that the HER properties of WC NPs are dramatically enhanced compared to that of all phase pure WC materials reported in recent years. This enhancement can be attributed to their unique structural and electronic properties, which can be exploited to improve the electrochemical properties of traditional non-noble metal material.

The Effect on Carburizing Process on Microstructure and Properties of 20MnCr5 Gear Steel

In this report, 20MnCr5 gear is characterized and analyzed under two carburizing heat treatment processes by optical microscope (OM) analysis, scanning electron microscope (SEM) analysis, X-ray diffraction (XRD) and Vickers hardness test. Results show that spherical and angular carbides can be obtained by a high concentration carburizing process for 20MnCr5 gear. Reheating and subsequent low-temperature tempering help refine the grains of the infiltration layer, reduce the residual austenite content in the permeable layer, and increase the thickness of the effective hardening layer.

The Influence of Carbon Particle Size in The Carburizing Process of ST-40 Steel to The Surface Hardness

This research aimed to determine the changes in the microstructure that occurred and changes in the hardness value of the steel surface. This research uses ST 40 steel and carbon powder with an average area of carbon particles 115,103µm 2 and 515,735µm 2. Steel and carbon were put in a closed container and heated at 780oC for 4 hours. After the carburizing process, the particle area was reduced to 110,051µm 2 and 440, 058µm 2. Raw material yields an average solubility of elements in Fe (β%) 5.99%. The solubility of the carburizing material element is higher in the smaller carbon grains. Likewise, the result of surface hardness after the carburizing process is harder by using small carbon granules.

Comparative Effect of Some Carbon Rich Materials on the Hardness Property of Carburized Low Alloy Carbon Steel

This work focuses on the effects of carburization process, on the hardness property of carburized low alloy carbon steel, at temperature of 890°C with varied soaking time of 1 hour, 2 hours and 3 hours, after which the samples were later quenched in air. The carbon rich materials used in this work include: coal dust, snail shell particulate, palm kernel shell and cow bone while 20% limestone was used as the energizer. Thirteen specimens were machined to specifications from 10mm diameter mild steel and each set of the specimens were randomly assigned to hardness test. Twelve pack boxes measuring 150mm x 75mm x 75mm was fabricated from gauge 18 mild steel. Carbon rich materials and specimens were carefully placed into the pack boxes, a specimen each was packed into the four boxes meant for coal dust, snail shell, carbonized palm kernel shell and cow bone respectively. Each box was labeled accordingly, and were loaded into heat treatment furnace and carburized at a soaking temperature of 890°C. At appropriate times, each sets of boxes were removed, open and air cool. Hardness testing of the various specimen were conducted using Vickers hardness test machine. Both coal dust, snail shell, palm kernel shell and cow bone were observed to have increase the hardness of the samples when compared with the as-received sample. As holding time of specimen increase in each carbonaceous materials, carbon diffusion and penetration increases which resulted to increase hardness values recorded in samples with 3 hours holding time.

The Effectiveness of the Carburizing Process on ST 42 Steel With Variations of Donor Media

Carburizing is a process of adding carbon content in steel by using solid media. This study aims to determine the effectiveness of the carburizing process on the hardness and depth of carbon diffusion on ST 42 steel with a variety of donor media. Meanwhile, the donor media used were teak wood charcoal, coconut shell charcoal, and graphite. The results of this study are the highest level of hardness in coconut shell charcoal, namely 815.39 HV, teak charcoal 715.5 HV, and the lowest hardness is graphite at 343.975 HV. While the highest average carburizing depth was coconut shell charcoal of 0.0133 µ, teak charcoal at 0.0085 µ, and graphite by 0.00416 µ. This shows that there are differences in the hardness value and the depth of carbon diffusion in the three types of donor media used in the carburizing process, so it can be concluded that the type of donor media can also affect the effectiveness of the carburizing process itself.

Structure, tribological properties, and the growth mechanism of in-situ generated TiC in titanium cermet

Titanium cermet combining metallic toughness with ceramic wear resistance has been proven to be a potential candidate for implanted joint material. In this work, titanium cermet was synthesized by means of the elevated temperature solid carburizing technology. The Ti13Nb13Zr alloy surface was found to be converted into TiC ceramic layer combined with a carbon strengthened diffusion zone underneath. The overall thickness of the carburized region grew to about 100 µm after 120 min carburization at 1,500 K. In order to clarify the growth behaviors of TiC ceramic layer, a growth mechanism is proposed. At the beginning of carburizing process, carbonaceous gas decomposed from carburizer due to high temperature and then converted to free atomic carbons through reduction reaction. Then, in-situ generated TiC ceramic layer possessing certain thickness formed on the surface, meanwhile, the inner carbon diffusion zone also grew inwards due to physical diffusion of carbon, and finally forming a gradient carbon distribution. In addition, the tribological behaviors of the new materials were evaluated through reciprocating ball-on-plate sliding wear tests in bovine calf serum. Although there was an increase in friction coefficient, the wear rate decreased by 59.6% due to the formation of the wear-resistant TiC ceramic layer. The wear mechanisms evolved from severe abrasive wear for bare Ti13Nb13Zr alloy to mild adhesive wear for titanium cermet.

Precipitation Criterion for Inhibiting Austenite Grain Coarsening during Carburization of Al-Containing 20Cr Gear Steels

AlN precipitates are frequently adopted to pin the austenite grain boundaries for the high-temperature carburization of special gear steels. For these steels, the grain coarsening criterion in the carburizing process is required when encountering the composition optimization for the crack-sensitive steels. In this work, the quantitative influence of the Al and N content on the grain size after carburization is studied through pseudocarburizing experiments based on 20Cr steel. According to the grain structure feature and the kinetic theory, the abnormal grain growth is demonstrated as the mode of austenite grain coarsening in carburization. The AlN precipitate, which provides the dominant pinning force, is ripened in this process and the particle size can be estimated by the Lifshitz−Slyosov−Wagner theory. Both the mass fraction and the pinning strength of AlN precipitate show significant influence on the grain growth behavior with the critical values indicating the grain coarsening. These criteria correspond to the conditions of abnormal grain growth when bearing the Zener pinning, which has been analyzed by the multiple phase-field simulation. Accordingly, the models to predict the austenite grain coarsening in carburization were constructed. The prediction is validated by the additional experiments, resulting in accuracies of 92% and 75% for the two models, respectively. Finally, one of the models is applied to optimize the Al and N contents of commercial steel.

Suppression of Austenite Grain Coarsening by Ferrite Pinning during Pseudo-carburizing Treatment

Grain coarsening prevention while accelerating the carburizing process is critical for the manufacturer for case hardening components such as gears to improve efficiency. In this research, a novel method is proposed to prevent austenite grain growth by introducing the ferrite phase that could retard the austenite boundary movement. The addition of aluminum promotes the ferrite phase. Aluminum as strong ferrite former raises the A3 temperature so that the ferrite phase is present at high carburizing temperature. The effect of 1 wt.% aluminum on the microstructure evolution during pseudo-carburizing treatment in 20CrMn steel is investigated in details. It is shown that the formation of ferrite during pseudo-carburizing at 930 °C for 5h prevents austenite grain coarsening. The obtained mechanical properties are similar to non-aluminum added 20CrMn steel pseudo-carburized at 830 °C for 16h. When 20CrMn was pseudo-carburized at 930 °C for 5h, significant austenite grain growth was observed, which result in low impact toughness after the subsequent quenching and tempering treatment. The “ferrite pinning” effect effectively inhibits the grain growth at high temperature, revealed by metallography investigation.

Peningkatan kekerasan dan ketahanan korosi paduan Fe-2,9Al-0,4C dengan proses karburisasi padat

Fe-Al-C alloy is a superior and economical new alloy to replace the ferritic stainless steel, whereas aluminum replaces chromium, which is relatively expensive. Some applications of Fe-Al-C alloys require hardness at the surface. This study aims to determine the effect of the temperature carburizing process on the hardness and corrosion resistance of Fe-2,9Al-0,4C alloys. Material used is Fe-2,9Al-0,4C steel alloy. Surface hardening using a solid carburizing method. The solid carburizing process carried out by the holding time for 3 hours at various temperatures of 850°C, 900°C, 950°C, 1000°C, and 1050°C. Carburized is used in the form of powder coal and MgCO3 catalyst. Tests carried out are chemical composition, microstructure, hardness, and corrosion tests. The test results show that the chemical composition of the Fe-2,9Al-0,4C alloy contains elements of 2.91% Al and 0.40% C. Microstructure formed is ferrite and pearlite with a dendritic pattern. The martensitic structure formed at 950°C, 1000°C, and 1050°C. The Carburizing process increases the hardness value where the higher temperature carburizing process, the higher hardness values until it reaches a maximum temperature of 1050°C with a hardness value of 1040.5 kg/mm2. The highest corrosion resistance value occurs after the 850°C carburizing process at a rate of 41.58 mpy corrosion (up 40.9% of the raw material). At a higher temperature carburizing process lowers the corrosion resistance of the alloy Fe-2,9Al-0,4C.