The mechanism of natural age-strengthening of grey cast iron: PEC-ageing

Effect of brass-alloy machining-swarf additive on the microstructure, hardness and toughness of gray cast iron.

The effect of heat treatment on the electrical resistance and thermal conductivity of synthetic grey cast iron is considered. The mechanism of forming phases and structural components of cast iron depending on the mode of heat treatment (HT) is presented. Experimental dependences of electrical resistance and thermal conductivity on cast iron composition and heat treatment parameters are found out. Recommendations are proposed that make it possible to select one or another alloy for real products with the required set of electrophysical characteristics. The importance of the presented studies is stressed, the results of which will allow replacing traditional expensive high-resistance materials with less expensive gray cast iron.

To meet the mechanical property requirements of gray cast iron for the shells of coal mine explosion-proof equipment and investigate the effect of austenitizing temperature on the microstructure and mechanical properties of gray cast iron, isothermal quenching was conducted at four austenitizing temperatures (890 °C, 910 °C, 930 °C, and 950 °C), with cast samples as the control group. The microstructure was using a scanning electron microscope, and the mechanical properties were tested using a universal tensile testing machine, a drop-weight impact testing machine and a hardness tester. The results show that the matrix microstructure of gray cast iron transforms from ferrite + pearlite to ausferrite after isothermal quenching, and the proportion of ausferrite increases gradually with the rise of austenitizing temperature. At an austenitizing temperature of 930 °C, the hardness of the sample reaches a maximum value of 247.6 HBW, which is 31.9% higher than that of the cast sample. At 910 °C, the impact energy and tensile strength achieve the optimal values of 9.59 J and 219 MPa, respectively, with an increase of 6.43 J and 51 MPa compared with the cast sample. Comprehensive analysis indicates that the austenitizing temperature of 910 °C can improve the strength while maintaining good toughness, which makes it more suitable for application scenarios requiring both strength and toughness such as coal mine explosion-proof equipment.

Heterogeneous Deep Gray Matter Iron Deposition Patterns across Multiple Sclerosis Subgroups Defined by the Clinico-Radiological Paradox.

This study presents a comprehensive investigation into the corrosion behavior of grey cast iron in a biodiesel–diesel–ethanol fuel blend (B20D70E10; 20% biodiesel, 70% diesel, 10% ethanol) and its associated fuel degradation. Immersion tests were conducted under two exposure conditions: prolonged ambient exposure at 25 °C for 962 h and accelerated exposure at 60 °C for 504 h. The novelty of this work lies in the integrated evaluation of grey cast iron corrosion and concurrent fuel degradation in a BDE blend under dual exposure conditions. At 25 °C, grey cast iron exposed to B20D70E10 exhibited a corrosion rate of 0.1924 mpy, higher than petroleum diesel (B0, 0.0726 mpy) but lower than pure biodiesel (B100, 0.8387 mpy). At 60 °C, the corrosion rate increased significantly to 0.6653 mpy, exceeding both B0 (0.1109 mpy) and B100 (0.2564 mpy), highlighting the dominant influence of temperature in ethanol-containing blends. Surface morphology revealed localized pitting and deposits, while FTIR confirmed chemical modification of the metal surface. Fuel characterization showed moderate changes in density, viscosity, and flash point, with most properties remaining within acceptable limits. Fuel degradation indices indicated lower oxidative degradation for B20D70E10 than B100, though greater than B0.

AI-Driven Decision Support for Multi-Objective Optimization of Turning Parameters in Grey Cast Iron Machining

Molecular dynamics analysis of friction wear in gray cast iron brake discs: an atom-scale investigation of graphite/matrix interface behavior

The article presents a comprehensive analysis of the problem of machining high-strength cast iron with vermicular graphite (CGI) using cutting tools made of polycrystalline cubic boron nitride (PCBN).The relevance of the study is determined by the importance of CGI in the automotive industry for improving engine performance and reducing harmful emissions. However, its widespread use is hampered by low machinability, which is significantly inferior to gray cast iron. Based on the analysis of scientific documents, the main reasons for the low stability of PCBN tools have been systematized. The unique microstructure of PCBN is recognized as the key problem: vermicular graphite combined with low sulfur content. This leads to intense thermomechanical stresses and prevents the formation of a protective sulfide layer (MnS), which effectively reduces wear when machining gray cast iron. As a result, thermochemical and diffusion wear become the dominant wear mechanisms, accompanied by the penetration of iron into the tool structure and the destruction of boron nitride grains. The article discusses possible ways to solve the problem, in particular, development of new PCBN grades with improved binding materials. Application of innovative processing methods, such as modulation-assisted machining (MAM). It is shown that MAM converts continuous cutting into intermittent cutting, which reduces thermal loads and significantly increases tool life. In addition, the review highlights that cutting speed and thermal management strategies play a crucial role in controlling the intensity of diffusion wear. Optimizing these parameters can partially compensate for the lack of a lubricating sulfide layer and improve the overall machining performance of CGI. Moreover, recent studies indicate that controlled cooling techniques can further stabilize the cutting zone, thereby reducing tool degradation and enhancing dimensional accuracy during CGI machining.

Microstructure and Mechanical Properties of Damaged Gray Cast Iron Components Remanufactured by Multi-Pass Laser Cladding for Nuclear Power Plants

Developing brake pad friction materials is critical to enhancing the automotive brake system's performance. Solid lubricants play a crucial role in reducing wear and maintaining friction under demanding conditions. While molybdenum disulfide (MoS 2 ) remains widely used, recent progress in 2D materials has opened new possibilities. Among these, titanium‐based MXenes (Ti 3 C 2 T x ) have emerged as promising candidates due to their mechanical strength, thermal resilience, and inherent self‐lubricating properties. This study presents the first comprehensive evaluation of Ti 3 C 2 T x and MoS 2 as a solid lubricant in automotive brake pad composites. A fixed matrix composition of steel fibers, barium sulfate, phenol‐formaldehyde resin, and iron oxide is maintained across three formulations: a MoS 2 ‐based, a Ti 3 C 2 T x ‐based, and a hybrid combining both additives. The samples are fabricated adopting powder metallurgical techniques. Samples evaluation is conducted to analyze their thermal, mechanical, physical, and tribological properties. Microstructural analyses are performed using scanning electron microscopy and energy‐dispersive X‐ray spectroscopy. Tribological performance is assessed through pin‐on‐disk against a gray cast iron disk. Results show that Ti 3 C 2 T x ‐containing composites excel in all aspects compared to MoS 2 . The hybrid formulation composite reduces specific wear rate by 16.5%, while the Ti 3 C 2 T x ‐only composite achieves a 48.5% reduction relative to the MoS 2 composite.

This paper presents a detailed failure analysis of an automotive clutch pressure plate subjected to severe thermal loading conditions during operation. The study investigates the material’s chemical composition, microstructural evolution, and mechanical property changes resulting from thermal exposure. The base metal was identified as grey cast iron conforming to FG 260 standards, ensuring a baseline for understanding its expected behavior. The investigation reveals significant microstructural transformations, including the formation of martensite, tempered martensite, and bainite, which arise due to the cyclic heating and cooling typical of clutch service. These phase changes adversely affect the mechanical integrity of the pressure plate, contributing to crack initiation and propagation. The failure was isolated to the pressure plate, with related clutch components remaining unaffected, highlighting the localized impact of thermal stresses. The findings emphasize the critical interaction between material composition, thermal history, and microstructure in determining component longevity. The study provides valuable insights to guide future improvements in material selection, heat treatment processes, and operational practices to enhance the durability of friction materials in automotive applications. Keywords: Thermal Fatigue, Microstructural, Clutch Pressure Plates, Commercial vehicles, failure analysis, mechanical property, FG 260 standards, powertrain, Diaphragm Spring, Clutch Cover, IS 6331 standards, Clutch, Pressure plates, Microstructure, Martensite, Grey cast iron, Thermal load, Thermal cracks, Heat discolouration

Spur gears are commonly used for power transmission in mechanical systems. This research analyzes and compares spur gears made of four different materials - Aluminum alloy, Gray Cast Iron, Structural steel and low alloy steel AISI 4140. FEA was conducted to determine the effects of deformation, von Mises stress, and strain on the gearbox components, which indicated that they will perform adequately in relation to the loads associated with vehicle operation. This comparison evaluated the mechanical behavoir within the operating conditions for gearbox components, such as von Miss stress and Von Miss strain. The FEA and mechanical testing demonstrated that these types of materials had comparable properties. The comparative analysis of mechanical properties of these materials and the design of the gearbox should be useful in helping to determine appropriate material selection for the manufacture of spur gears to be used in mechanical applications to transmit power.

Performance and wear mechanism of PCD tools in precision turning gray cast iron HT250 under dry and cryogenic internal cooling conditions

Microstructure, residual stress and electrochemical corrosion behavior of gray cast iron subjected to massive laser cavitation peening

The foundry industry is seeking an ecological alternative to synthetic molding resins. This study evaluates the technological properties of core sands bonded with biodegradable polylactide (PLA). Cores prepared on a 2% quartz sand matrix were subjected to casting processes using two alloys with extremely different pouring temperatures: gray cast iron (approx. 1200 °C) and AK11 silumin (approx. 710 °C). The research methodology included macroscopic assessment, dimensional analysis using 3D scanning (GOM Inspect), and qualitative knock-out assessment supported by numerical temperature field simulation. The results showed that the high crystallization temperature of cast iron leads to complete thermal degradation of the binder, ensuring excellent knock-out properties.

Abstract This study investigates the behaviour of high-chromium stainless steel 304/high-carbon grey cast iron (HCSS 304/HCGCI) bimetallic metal matrix composite alloys (MMCAs) produced via green sand mold casting. The work focuses on the interaction between the molten HCGCI layer and the solid HCSS 304 functional layer during solidification. Elevated pouring temperature promoted effective metallurgical bonding by enabling substantial heat transfer from the liquid HCGCI to the solid HCSS 304 plate. During the uphill casting process, carbon and silicon diffused toward the steel, while chromium migrated from the HCSS 304 into the HCGCI. Ultrasonic non-destructive testing and destructive characterization confirmed the formation of a permanent diffusional bond at the bimetal interface. The interface was observed to be free of defects and exhibited a well-developed dual-phase microstructure comprising α-ferrite, γ-austenite, and minor martensite/carbide constituents. Post-solidification mechanical and microstructural analyses revealed that tensile strength, ductility, hardness, and impact toughness decreased with increasing HCGCI layer thickness. Overall, the findings demonstrate that HCGCI layer thickness significantly influences the mechanical performance and interfacial integrity of HCSS 304/HCGCI bimetallic systems, providing important guidance for optimizing bimetal casting processes.

Grey cast iron brake discs are widely used in automotive applications due to their excellent thermal and mechanical properties. However, stricter environmental regulations such as Euro 7 demand improved surface durability to reduce particulate emissions and corrosion-related failures. This study evaluates multilayer coatings fabricated by Laser Metal Deposition (LMD) as a potential solution. Two multi-layer systems were investigated: 316L + (316L + WC) and 316L + (430L + TiC), which were primarily reinforced with ceramic additives to increase wear resistance, with their influence on corrosion being critically evaluated. Electrochemical tests in 5 wt.% NaCl solution (DIN 17475) revealed that the 316L + (316L + WC) coating exhibited the lowest corrosion current density and most stable passive behavior, consistent with the inherent passivation of the austenitic 316L matrix. In contrast, the 316L + (430L + TiC) system showed localized corrosion associated with micro-galvanic interactions, despite the chemical stability of TiC particles. Post-corrosion SEM and EDS confirmed chromium depletion and chloride accumulation at corroded sites, while WC particles exhibited partial dissolution. These findings highlight that ceramic reinforcements do not inherently improve corrosion resistance and may introduce localized degradation mechanisms. Nevertheless, LMD-fabricated multilayer coatings demonstrate potential for extending brake disc service life, provided that matrix-reinforcement interactions are carefully optimized.

Disc brake rotors are essential safety components in motorcycles, where their thermo-mechanical behavior under dynamic braking directly influences performance, durability, and reliability, particularly at high speeds. Conventional Gray cast-iron rotors, although widely used, often suffer from excessive thermal stress, significant deformation, and inadequate heat dissipation under severe braking conditions. Aluminium metal matrix composites (AMMCs) present advantages such as reduced weight and enhanced strength but encounter challenges including thermal expansion mismatch, localized stress concentration, and instability at elevated speeds. Despite their potential, few studies have explored microstructural tailoring of AMMCs to optimize their thermo-mechanical performance for practical braking applications. To address this, the present study systematically modifies AMMC constituents by incorporating tungsten carbide (WC) reinforcement while proportionally reducing aluminium content. A solid drilled disc rotor from a Bajaj Pulsar 150 cc was modeled in ANSYS Workbench and analyzed under transient coupled-field conditions across four braking speeds (800–2000 rpm). The work integrates transient Finite Element Analysis with experimental validation to compare Gray Cast Iron and three AMC formulations. Increasing WC reinforcement by 2% and reducing aluminium content improved thermal conductivity, hardness, and wear resistance while minimizing stress and deformation. Simulation and experimental results revealed that Gray Cast Iron experienced higher stress and temperature rise, whereas modified AMC2 demonstrated superior performance with lower peak temperatures, stable stress distribution, and minimal deformation. These findings highlight modified AMC2 as a promising material for next generation high-performance brake rotors, offering enhanced safety, durability, and weight efficiency.

In this study, the natural frequency changes, induced by vibratory stress relief, were ana-lysed. Vibratory stress relief (VSR) is a possible alternative to thermal stress relief (TSR), which can be applied to welded structures and castings to reduce residual stresses. In this paper, acoustic-based natural frequency measurements will be presented to investigate the effect of VSR treatment. Natural frequency measurements were taken on large disc-type grey cast iron components, before and after the VSR treatment and we have analysed the results for five sim-ilar castings from the same batch. The natural frequencies change when the stress state of the workpiece changes. Changes in the frequencies have been examined, and we have identified a pattern for a specific treatment parameter setting. Measurement images – spectrograms - were generated to visualize the frequency response, where stress-induced variations appeared as shifts in resonance bands. Across all five tested components, a consistent decrease in dominant natural frequencies was observed. While the results mostly align with theoretical expectations, they also highlight the complex, time-dependent behaviour of residual stress redistribution. Fur-ther long-term monitoring is recommended to clarify post-treatment evolution and material-specific responses. The results can open new directions for the automotive and heavy industry to effectively reduce residual stresses and monitor the performance of the workpieces.