Carburized Samples Research Articles

The effect of surface roughness and carburized depth on wear resistance in 16MnCr5 case hardening steel

Purpose Today, wear and tear is a metaphor whose cost cannot be ignored by real sector. For this reason, many sectoral and academic studies are carried out to minimize the wear effect. This study aims to create a perspective against wear problems for the automotive industry as well. Design/methodology/approach The 16MnC5 material, which is used as the U-joint material in the powertrain of the automotive industry, was subjected to heat treatment such as normalization and carburization at certain temperatures and duration. By subjecting the resulting carbide thickness to the abrasion process, the maximum effective heat treatment parameters against wear were determined. Findings It has been determined that the ideal cementation condition for 16MnCr5 steel to be used in the wear system is carburized samples at 900 °C for 3.5 h with a hardness depth of 1.04 mm. Originality/value The variation in which the surface hardness thickness and surface roughness obtained by different heat treatment variations of the U-joint part, which is one of the cardan shaft components that provide power transmission of heavy commercial vehicles, show the best wear resistance, were investigated. As a result of this study, the study is to prevent the waste of limited materials in the world and to reduce the repair and maintenance costs of commercial vehicles. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2024-0152/

A Time‐Saving Method for Evaluating the Fatigue Strength of Carburized High‐Alloy Steel Containing Carbides

To propose a time‐saving method for evaluating the fatigue strength of carburized steel, the fatigue behavior and fracture mechanism of carburized 14Cr14Co13Mo5 steels are studied by the rotary bending fatigue tests. It is found that the fatigue crack initiation site changes from surface to internal after carburizing due to the residual compressive stress and carbide cluster caused by the carburization. Besides, a notable correlation between the stress intensity of the cracked carbides at fatigue crack initiation site and fatigue life is observed in the carburized samples. This correlation allows for the estimation of fatigue strength at long conditional life based on samples tested at relatively high stress amplitudes with short lives, achieving a prediction error within 10% for the material studied. A significant time saving of ≈65% compared to the staircase method is achieved. The proposed method has significant implications for improving the efficiency fatigue strength evaluation in carburized steels containing carbides.

A novel route of carburizing through microwave hybrid heating

Abstract Carburizing is a surface treatment process by diffusing carbon into the steel. These days, manufacturing industries demand highly efficient processes that consume low power. Microwave processing is a newly evolving process that consumes low power. This study proposes a novel route for carburizing mild steel (substrate) through experimental and simulation studies using a microwave heating. Charcoal powder was used as a susceptor to convert microwave energy into heat energy and to deposit carbon on the surface of the specimen. The mild steel specimens were exposed to the microwave power input of 900 W and 360 W for exposure time of 1500 s and 1980 s naming it as S2 and S3 respectively. The microstructural analysis of specimens S2 and S3 confirms the formation of pearlite structures at the surface. However, the amount of pearlite structure was significantly higher for the S3. The higher carbon content is confirmed through energy-dispersive x-ray spectroscopy (EDS) analysis of specimen S3. The average hardness of the S3 specimen was determined to be 220.8 HV, which shows an increase of 38.36% compared to the S1 (base metal). x-ray diffraction (XRD) results indicate the additional cementite peaks (Fe3C) and ferrite-confirming phase transformations for carburized samples. The wear analysis of S2 and S3 was conducted through pin-on-disk testing. The peak COF of 0.73 and 0.64 was observed for S2 and S3 respectively. The hard surface of S3 resists the penetration of the counter body to a greater extent due to the fine morphology of pearlite. From the FEM study, the maximum value of 7.96 × 10 3 (V/m) was determined at the center region for the electric field distribution in the microwave cavity, which is the optimum value for efficient heating. The maximum temperature of the mild steel obtained during the carburization process was 900 °C in 1800 s. The microwave carburizing process requires relatively less time than the conventional carburizing process which will save energy consumption.

Tribological performance of low-temperature plasma carburized AISI 420 martensitic stainless steel

Plasma carburizing has emerged as a potent technique for improving the wear resistance of stainless steels, and sustaining or improving corrosion resistance through a suitable choice of process parameters. This study evaluated the impact of plasma carburizing time and temperature on the tribological behavior of AISI 420 martensitic stainless steel through dry-sliding wear tests in a ball-on-disk configuration. Two different treatment sets were conducted to assess the impact of carburizing time and temperature on the wear performance of the treated AISI 420 steel. The first group encompassed treatments at temperatures spanning from 350 to 500 °C, with fixed treatment times of 8 and 12 h. The second group involved treatments at a temperature of 400 °C for durations spanning 12 to 48 h and at temperature of 450 °C for durations between 4 and 16 h. To facilitate the discussion of wear test results, microstructural analysis was performed using metallographic analysis, X-ray diffraction, and microscale hardness measurements. Microstructural characterization results revealed that the carburized surface consists of an outer layer followed by a diffusion layer. The diffusion layer is primarily composed of the α′C phase, while the outer layer contains α′C and Fe3C (for low-temperature and short-time treatments) and Cr/Fe-carbides primarily formed due to the α′C decomposition into Fe–α phase (for the studied higher-temperature and longer-time treatments). Wear test results suggest that the surface structure and composition of the treated material exert substantial influence on its tribological behavior. Carburized layers free from Cr-carbide precipitation exhibit lower wear and friction coefficients. The decomposition of α′C into Fe-α and Cr/Fe-carbides leads to an elevation of friction and wear coefficients. Finally, carbon enrichment does not alter the wear mechanism, as both uncarburized and carburized samples exhibited microabrasion and oxidative wear.

Determination of Optimum Ratio of Selected Carbonaceous Materials on Mechanical and Corrosion Behavior of Carburized Mild Steel

This work is centred on the determination of optimum ratio of selected carbonaceous materials of A(40% Snail shell + 40% Animal bone), B(60% Snail shell + 20% Animal Bone), C(20% Snail shell + 60% Animal bone), D(50 Snail shell + 30 Animal bone) and E(30 Snail shell + 50% Animal bone), the mechanical properties and corrosion behaviour of carburized mild steel. Which were carburized at single austenitic temperatures of 1000°C, soaked at single carburizing time of 5hr, at the treatment temperature and samples were then quenched in water. Before the carburization process, standard test specimens were prepared from the received sample for testing hardness, tensile strength, wear, and microstructure analysis. After the carburization process, the test samples are subjected to standard testing to generate data on the ultimate tensile strength and wear rate of the carburized samples. Research shows that the mechanical properties of mild steel are strongly influenced by each of the mixed ratios of the carbonaceous material (Such as Snail shell and Animal Bone). An improved hardness values in all the samples were observed, with sample A having the highest hardness value of 59.05 RHC while sample B and sample C have the highest wear resistance value of 0.090. The samples were immersed in 0.3M H2SO4 solution for potentiodynamic studies. There results show that sample E had the least corrosion rate of 8.1809 mpy hence is less prone to corrosion attack in acidic environment than others. These samples are found to be useful in automobile industry.

Stress Field Simulation and its Experimental Verification of Carburizing-Quenching Process Performed on 18CrNiMo7-6 Steel

The carburizing and quenching process of 18CrNiMo7-6 steel was performed through simulation methods and experiments. The study was carried out to accurately predict the residual stress distribution of carburized samples after the quenching process. The stress and retained-austenite amount were measured via X-ray diffraction. Similarly, the carbon content was determined using a carbon sulfur analyzer, respectively. A detailed model with the coupling of thermal, metallic, and mechanical fields was built to predict the evolution of the stress field during the quenching process. The carburized “thoroughly” specimens at different carbon potentials were used to obtain the required mechanical property parameters and dilatometric parameters for FEM simulation. According to the results, the martensite transformation kinetic parameters α value of 18CrNiMo7-6 alloy steel should be 0.0202. With the increase of carbon content, the changing trend of the transformation plasticity coefficient K appeared as a 'tick' shape. A compressive residual stress field was generated at the carburized layer surface after the quenching process, and the maximum value of 340 MPa occurred at ~ 0.9 mm below the surface. The carbon profile and residual stress fields predicted from the FEM simulation corresponded closely to the experimentally determined results.

Carburization behavior at elevated temperatures and mechanical properties of a hot stamped complex phase steel

As a lightweight construction strategy, hot stamped parts of ultra-high-strength steels with tailored properties are increasingly used for crash relevant components in car bodies, e.g., as B-pillars. With the process of tailored carburization, parts can be reinforced locally without increasing the sheet metal thickness. Thus, this process has the potential to be applied to lightweight components for no deformation zones, e.g., in the battery housings. Standardly, carburization is performed at 950 °C, with the highest strengths achieved at long times of up to 6 h, which prolongs the total process time. By raising the temperature, the carbon diffusion increases, which enables a reduced heat treatment time and, consequently, a shorter process time. Therefore, the objective of this study is to investigate the influence of elevated carburization temperatures on the mechanical properties of a carburized and hardened complex phase steel, CP-W® 800. A single carburization step at the enhanced temperatures leads to an embrittlement of the samples. Hence, an additional diffusion-annealing step is implemented to homogenize the carbon content, without enlarging the total heat treatment time. Depending on the time allocation of carburization and diffusion, the application of the diffusion annealing step results in higher strengths and ductility compared to only carburized samples.

Surface integrity and bending fatigue behavior of aeronautic gear steel under combined carburized treatment and shot peening

The carburized treatment combined with shot peening were introduced to improve fatigue behavior of aeronautic gear steel. Surface integrity and fatigue behavior after carburizing and combined treatment were systematically analyzed. Results indicated that surface roughness, microhardness and residual compressive stress were increased after combined. Meanwhile, average size of ultra-fine grains was reduced to 0.495 μm. Fatigue limit was increased from 720 MPa of carburized samples to 890 MPa treated by combined. Moreover, higher shot peening jet presure in combined treatment does not necessarily lead to better fatigue limit. Residual compressive stress was an important factor affecting fatigue cracks propagation mode.

Improving low temperature degradation of 3Y-TZP ceramics via high temperature carburizing

3Y-TZP ceramics are prepared by solid state method and surface carburization process, and the effect of surface carburization on its the low temperature degradation is studied. The conventional sintered samples completely lost its mechanical properties after aging for 15 h, while the failure time of the surface carburized samples are 300 h. In addition, the nuclear growth rate of the surface carburized samples (αd) and the nucleation rate (Nr) is lower than that of sintered samples, αd plays a dominant role in the degradation process at low temperature and is the key factor determining the aging rate. At the same time, it is found that carbon is dissolved in zirconia lattice in the form of electrically neutral atoms, which will not destroy the original charge balance and produce new oxygen vacancies when entering the interstitial site. More importantly, the precipitation rate of Y3+ from zirconia lattice is the key factor to determine the low-temperature phase transition of tetragonal-monoclinic(T-M). The treatment method of surface carburization has significantly improved the low-temperature degradation performance of 3Y-TZP ceramics, which provides a basis for the application of zirconia ceramics in low-temperature and humid environment.

Effect of carbon concentration and carbon bonding type on the melting characteristics of hydrogen-reduced iron ore pellets

Decarbonization of the steel industry is one of the pathways towards a fossil-fuel-free environment. The steel industry is one of the top contributors to greenhouse gas emissions. Most of these emissions are directly linked to the use of a fossil-fuel-based reductant. Replacing the fossil-based reductant with green H2 enables the transition towards a fossil-free steel industry. The carbon-free iron produced will cause the refining and steelmaking operations to have a starting point far from today's operations. In addition to carbon being an alloying element in steel production, carbon addition controls the melting characteristics of the reduced iron.In the present study, the effect of carbon content and form (cementite/graphite) in hydrogen-reduced iron ore pellets on their melting characteristics was examined by means of a differential thermal analyser and optical dilatometer.Carburized samples with a carbon content <2 wt% did not show any initial melting at the eutectic temperature. At and above 2 wt%, the carburized samples showed an initial melting at the eutectic temperature irrespective of the carbon content. However, the absorbed heat varies with varied carbon content. The carbon form does not affect the initial melting temperature, but it affects the melting progression. Carburized samples melt homogenously, while melting of iron-graphite mixtures occurs locally at the interface between iron and carbon particles, and when the time is not long enough, melting might not occur to any significant extent. Therefore, at any given carbon content >2 wt%, the molten fraction is higher in the case of carburized samples, which is indicated by the amount of absorbed melting heat.

A novel metallurgical technique for the preparation of soft magnetic iron carbide from low-grade siderite

Iron carbide (Fe3C) has attracted widespread attention as a functional material, catalyst, and magnetic material. In this study, soft magnetic Fe3C was prepared by carburization roasting, magnetic separation, and acid leaching using low-grade siderite as the raw material. The effects of carburization, subsequent magnetic separation, and acid leaching of the carburized samples on their magnetic properties were studied using a vibrating sample magnetometer (VSM), and the mechanisms of these methods were also studied. The final samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), VSM, and Mössbauer spectroscopy. Under optimized conditions, an iron carbide material comprising assaying 92.08% Fe and 6.94% C with a corresponding iron recovery rate of 73.50% was obtained. The saturation magnetization, the remanence, and coercivity values of the obtained iron carbide were 136.10 emu/g, 1.84 emu/g, and 39.11 Oe, respectively. Furthermore, Na2SO4 and NaOH were found to be useful additives for improving the carburization efficiency of iron carbide, enlarging iron carbide particles, improving the embedding relationship between iron carbide and gangue, and enhancing the dissolution of gangue in acid. The proposed technique is promising for the preparation of magnetic iron carbide materials with good soft magnetic performance.

Quasi-Non-destructive Characterization of Carburized Case Depth by an Application of Centerless X-ray Diffractometers

A new application of a centerless x-ray diffractometer was proposed that goes beyond residual stress measurements during the regular operation of such equipment. During depth residual stress measurement, it is possible to fit the measured interference function of the ferrite (211) with a different number of curves as a function of depth. The different curves corresponded with the appearance of ferrite fractions with different grain sizes and concentrations in ferrite, perlite, bainite, or martensite. Accordingly, different microstructures were non-destructively detected through the thickness of the carburized layer, and a good correlation was found with results from metallography and hardness testing. This novel method was validated on solid and gas carburized samples, but more work is needed to apply it to other microstructures.

Carburization-Based Optimization of AISI 8620 Steel Using Rice Husks and Charcoal as Carburizers

This study was centered on improving the mechanical properties of AISI 8620 steel using the carburization technique. The failure in service conditions of many steel components such as cams, gears, and shafts necessitated the research as it demands that they possess both high wear-resistant surfaces and tough shock-resistant cores. Standard test samples prepared from the steel material were subjected to a pack carburization process using rice husk and charcoal as carburizers, and the energizer – calcium trioxocarbonate (IV) at temperatures of 800, 850, 900, and 950 °C, and held for 60, 90, and 120 minutes. The samples were quenched in water and tempered at 500°C for 60 minutes. After the pack hardening process, the test samples were subjected to tensile, impact, and hardness tests. From the data obtained, ultimate tensile strength (UTS), Hardness, Young’s Modulus, engineering strain, and impact strength were calculated. The case and core hardness of the carburized samples were noted, and an optical microscope was used to observe the microstructural features of the case-hardened, quenched, and tempered samples. The responses (mechanical properties of steel) were optimized using response surface methodology to obtain the optimum carburizing conditions-temperature and holding time. Results showed that the sample’s microhardness core and microhardness case increased from 253 to 327 HV and from 243 to 339 HV as the holding time increased from 60 to 120 minutes, indicating an appreciable increase in the mechanical property of the samples. The optimum carburizing conditions were at a temperature of 885 °C and a holding time of 120 minutes. Hence, the carburization of AISI 8620 steel using rice husk and charcoal as carburizers improved the steel material’s case, core, and mechanical properties.

Low-pressure hollow cathode plasma source carburizing technique at low temperature

A low-pressure hollow cathode plasma source carburizing was developed as a novel surface treatment technique based on the active screen plasma carburizing combined with hollow cathode sources. The cylindric cathodic cage with array holes was made of pure graphite, where the hollow cathode graphite tubes were inlaid on. A pulsed high voltage power with a peak voltage of 800 V and a pulse frequency of 30 kHz was supplied to ignite the hollow cathode discharge inside graphite tubes at a low pressure less than about 300 Pa using a gas mixture of CH 4 + 90%H 2 . The hollow cathode plasma source together with the pulsed high voltage power realized a high biasing current on the carburized samples at low pressure, and produced an enhanced heating except the thermal radiation by the cathodic cage. The graphite cathode as a carbon source besides the gas precursor provided an additional carbon potential. The AISI 304L austenitic stainless steel was carburized at a low temperature of 450 °C for a treatment time of 6 h with a bias of 200 V under the carburizing pressure of 50 Pa and 300 Pa, respectively. It was observed that the carburizing case at 50 Pa was about 13 μm with a higher surface carbon concentration of about 6.5 at.% and a higher hardness of about HV 0.25 N 8.5 GPa compared with that at 300 Pa. The carbon-expanded austenite (γ C ) phase was observed by the x-ray diffraction of both the carburizing cases. The metastable high carbon carbide Fe 5 C 2 only appeared at 50 Pa, which was attributed to high carbon potential at the lower pressure. Therefore, an increased carburizing efficiency at the low temperature was obtained by the low-pressure hollow cathode plasma source carburizing technique using a pulsed high voltage power. • Hollow cathode plasma source is utilized in low temperature plasma carburizing. • Pulsed high voltage is used in graphite hollow cathode discharge at low pressure. • High sample biasing current with enhanced heating is realized by plasma source. • Graphite cathode provides additional carbon potential besides the gas precursor. • Thick carburizing case with metastable carbide and high hardness is obtained.

Synergistic effects of a combined surface modification technology on rolling contact fatigue behaviors of 20CrMoH steel under different contact stresses

Ultrasonic surface rolling (USR), carburizing and the combined (Carburizing + USR) strengthening method were applied on the 20CrMoH steel, and the rolling contact fatigue (RCF) mechanisms of 20CrMoH steel subjected to different strengthening methods are analyzed. Results indicated that the combined strengthening method effectively increased the surface hardness value from 370 HV0.2 to 900 HV0.2, produced the highest residual compressive stress (RCS) value of −920 MPa and markedly reduced the surface roughness value to 0.48 μm. Under the Hertz contact stress of 2.02 GPa, the RCF life of the combined treated samples increased by 100% compared to the carburized samples, and the delamination mainly occurred. Surface roughness and RCS are important factors for anti-RCF failure.

Effect of Mn-dopant on carburization of the Fe3O4 catalysts in Fischer-Tropsch synthesis

By experimental and density functional theory (DFT) methods, we investigated the effect of Mn on the carburization of the Fe3O4 catalysts in Fischer–Tropsch synthesis. Freshly prepared MnxFe3-xO4 (x = 0, 0.27 and 1) nanoparticles as representative model bulk FTS catalysts were carburized by exposing to syngas. The oxide nanoparticles and the corresponding carburized samples were then characterized using XRD, XPS, TEM and MES. To mimic the experiments, a slab modelling the Fe3O4(311) surface doped with different number of Mn atoms were constructed in the DFT calculations. Our results showed that Mn doping hindered the carburization of Fe3O4 nanoparticles and stabilizes the reduction intermediate at FeO. This is attributed to the enhanced affinity of O atoms in the presence of Mn-dopant, making removal of O difficult. The work provides guidance for catalysts design and activation for FTS process.

Bending behavior of a hot stamped complex phase steel with tailored properties by local carburization

Concerning lightweight design, hot stamping of boron-manganese steels has developed to a state-of-the-art process for manufacturing safety-relevant car body parts in the last two decades. To further improve passenger safety, the idea of components with tailored properties has become even more important. Normally, these process variants aim to bring in so-called soft zones, where a fully martensitic microstructure is prevented to significantly improve ductility. The growing importance of battery electric vehicles and their special requirements call for alternative processes. Especially the battery and its housing are often referred to as a no deformation zone. Concerning this matter, the new process of tailored carburization can be advantageous, since it aims to locally improve strength rather than ductility. Regarding the field of application as a safety-relevant component, the crash behavior is of high interest. In recent years, the three-point bending test has prevailed as a suitable comparative test to estimate crash performance. Within this work, the influence of various carburization parameters on the bending behavior is analyzed. The results reveal that the additional carburization improves punch force at the cost of the bending angle. By analyzing locally carburized samples it is shown, that especially the carburization of the tensile loaded side within the deformation zone is crucial for local strengthening under bending load.

Modification of Hardness Properties Characterizing Carbon Steel American Society for Testing and Materials in Carbon Steel A36 Using Bagasse Ash from the Waste of Sugarcane Industries

In this work, the effect of bagasse ash from waste sugarcane industries on American society for testing and materials in carbon steel A36 (ASTM A36) was investigated. The ash caused the formation on the surface of the samples’ carbon sheet, thereby improving the hardness of the materials’ property. The samples were polished and cleaned in preparation for hardness tests (Rockwell) and microstructural investigation. Furthermore, the bagasse was sintered in a furnace at 400 °C for 3 h to bagasse ash. Additionally, the ash was sifted to a sample size of 100 μm and mixed with 100:0, 90:10, and 80:20 ratios of barium carbonate (BaCO3). The samples were calcined in a pack carburizing box between bagasse ash and BaCO3 at 950 °C for 8 h. The carburized samples were used to classify by Thermogravimetric Analysis (TGA), Energy Dispersive X-ray Spectroscopy (EDS), Optical Emission Spectroscopy (OMS), and Optical Microscopy (OM), respectively. The results revealed that 88% of carbon by weight of bagasse ash contributes to significant improvement in the mechanical properties of the ASTM A36 steel.

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.

Potential of Date-Seed/Snail Shells as a Carburizer for Enhanced Mechanical Properties of Mild-Steel

The suitability of date-seed/snail shells as a carburizer for enhanced mechanical properties of mild-steel using the packed carburization technique was investigated in this work. Standard tensile, impact and hardness test samples prepared from mild-steel were subjected to pack-carburization process using mixtures of date-seed and snail shell in the ratio 60:40 respectively at 800, 900, and 1 000 °C for 3 hours. The carburized samples were quenched in water at room temperature and further tempered at 300 °C for 30 minutes for residual stress relief of the quenching effect. The mechanical properties and optical microstructure of carburized specimen were performed. Results indicated an enhanced mechanical property of the carburized mild-steel using date-steel/snail shell as a carburizer compared to un-carburized same steel material. The tensile strength and hardness increased with increasing carburizing temperature, though with an associated decrease in ductility. The peak hardness (32.82 HRB) and tensile strength (521 MPa) with equivalent 31.28 and 51.45 percentage increments respectively were obtained at carburizing temperature of 1 000 °C. Hence, using date-seed/snail shell powder as a carburizer can enhance the mechanical properties of mild-steel.