Optimizing Material and Technology Selection for Cost-Effective Equipment Performance

LCC procedures are commonly used in building retrofit interventions for the evaluation of the costs and benefits of different solutions. LCC methods are also commonly applied to energy retrofit interventions according to UNI-EN 15459. However, these procedures can give significantly different results in relation to the methods used to define the economic and technical parameters used in the calculation. Several authors have highlighted how the uncertainties related to the quantification of the costs of initial investment and maintenance, the economic scenarios (inflation and interest rates), the costs of energy and labor and the "service life" of the components strongly influence the results and the assumption of different data sets can result in significantly different results. Several authors pointed out that it is necessary, prior to these procedures, to perform sensitivity analyzes, useful for understanding if and how each of these parameters can influence the results, which leads to the need to use probabilistic methods. The study reported here analyses the influence that different assumptions about the service life of building components have on the economic benefits brought by interventions of energy requalification. Specifically, through a specially developed probabilistic procedure, the influence on the global costs of different assumptions about the probability distributions and the specific parameters characterizing each of them related to the service life of components useful to realize the thermal insulation was evaluated. the envelope of existing buildings. In particular, four different probability distributions (normal, uniform, left triangular, right triangular), different values of the median have been taken into consideration for the same distribution amplitude and the global costs and the return time values have been evaluated. investment considering different alternative economic scenarios for inflation and interest rate.

The addition of third elements may help transform brittle D022-structured lightweight Al3Ti to a relatively ductile L12-structured (Al, M)3Ti (where M represents the third elements), thus increasing the ductility at the expense of hardness. Such a transformation could benefit the wear resistance of the alloy due to improved toughness if a proper balance between the hardness and ductility is achieved. In this work, a D022-predominant Al3Ti alloy (S-Al3Ti) and an L12-predominant (Al, Fe)3Ti alloy (S-Al67Ti25Fe8) were fabricated by arc melting. Change in wear resistance, corresponding to a D022-to-L12 transformation, caused by the addition of Fe as a representative third element, was investigated and compared with the wear resistance of a commercial Al-matrix composite reinforced by 30 wt.% SiC particles (S-Al/SiCp) as a reference material. It was observed that wear of the S-Al3Ti resulted from abrasion involving synergistic oxidation, leading to a larger volume loss. In contrast, the softer S-Al67Ti25Fe8 showed enhanced wear resistance, benefiting from improved toughness with reasonable hardness. During the wear testing, both the alloys exhibited better performance than S-Al/SiCp, a well-known lightweight composite. This study highlights that D022-to-L12 transformation enhances wear resistance due to increased toughness which can be adjusted using the addition of a third element.

Wear and enhancement of wear resistance – A review

Information about the actual history of cyclic loading in the actual state of the metal in equipment components must be used for analyzing the safety of power-generating units in operating nuclear power plants, in preparation for service-life extension, and to determine the moment of onset of rapid aging of the metal and the end of the period of stable operation. The properties of the exponential distribution function and probability functions which are constructed for various loading scenarios using the hypothesis of probabilistic summation of fatigue damage for estimating the γ-percentage residual service life of equipment components are examined. Probabilistic estimates of the service life for operating nuclear power plants make it possible to control effectively the residual service life of the components of a nuclear power plant on the basis of information provided by the diagnostics systems and by the systems monitoring the state of the metal and the data on loading parameters from the control systems.

Selecting suitable materials for automotive brake discs is an important process in the construction and assembly of braking systems. Brake discs or rotors are important components that convert kinetic energy into thermal energy to enable efficient braking and ensure vehicle and occupant safety. The choice of brake disc material is important to ensure optimum performance, reliability and durability under various operating conditions. Several important properties such as efficient heat dissipation, high mechanical strength, wear resistance and constant friction properties should be considered when choosing a suitable material for brake discs. Historically, Gray cast iron (GCI) continues to be the number one choice for brake discs due to its excellent heat transfer capabilities, effective vibration damping, and cost effectiveness. GCI effectively withstands the high temperatures and mechanical stresses encountered during braking, providing reliable and consistent performance. However, advances in materials science and engineering are researching alternative materials for brake disc applications Titanium alloys such as Ti-6Al-4V offer exceptional favour such as lightweight design, high-calibre strength, and corrosion resistance. These properties make titanium alloys suitable for certain applications that require reduced weight and increased performance. TMC combines a titanium matrix with ceramic reinforcements to improve performance compared to conventional materials. There are various factors to consider when choosing the brake disc material, such as: B. Vehicle type, weight, intended use (racing, daily driving, etc.), operating temperature, and cost considerations. Thorough testing and evaluation are performed to ensure that selected materials meet required performance criteria such as braking efficiency, durability, wear resistance and heat aging resistance. As the automotive industry continues to advance, there is more R&D exploring advanced materials such as carbon-ceramic composites for high-performance and luxury vehicles. These materials provide excellent braking performance, weight savings and long life. Research Significance: The study of material selection for automotive brake discs will show results in the performance, reliability, and safety of braking systems. The aim is to identify suitable materials that improve braking efficiency, durability and thermal stability. Efforts in this area have led to improved braking performance through the development of materials with optimal friction properties. These materials result in shorter braking distances, increased responsiveness, and improved overall braking efficiency. Additionally, research is focused on identifying lightweight materials that maintain structural integrity and heat dissipation capabilities. This weight savings contributes to improved fuel efficiency, lower emissions, and improved vehicle handling and performance. Durability and longevity are important aspects studied in research. Materials with high mechanical strength and wear resistance are selected to ensure long-term durability and long service life. Effective heat dissipation is also an important factor. The aim of the research is to find materials with good thermal conductivity and stability. This prevents brake slippage and ensures smooth, reliable braking performance even under the most demanding conditions. Cost-effectiveness is also a consideration, as researchers strive to find materials that balance performance, durability, and cost. Identifying cost-effective materials without compromising safety and performance is critical for widespread adoption in the automotive industry. Methodology: Weighted Sum Method: It method is the mathematical approach by combines many factors or criteria by assigning weights to each of them. A weighted sum is calculated by the means of multiplying the weight of each one element by the corresponding value and summing it up. This method allows comprehensive evaluation and ranking of alternatives based on their weighted scores. It provides a simple and effective way to consider multiple factors at once and make decisions. Alternate Parameters: GRAY CAST IRON (GCI), TMC, AMC 1 & AMC 2, TI-ALLOY (TI-6AL-4V). Evaluation Parameters: Friction coefficient tµ), Wear rate (x10^ {-6} mm^ {3}/N/m), Specific gravity (Mg/m^ {3}), Compressive Strength (MPa), Specific heat (Cp (KJ/Kg. K)). Result: From the result it is seen that Gray cast iron (GCI) got the first rank where as is the Ti-Alloy (Ti-6Al-4V) having the lowest rank. Conclusion: The first ranking material gray cast (GCI) is obtained with the best and suitable material for automotive brake disc.

This paper investigated the response of carburized 20CrNi2MoV steel to cryogenic treatment including microstructure and wear resistance. Two cryogenic treatment methods including cryogenic treatment at −80 °C (CT) and deep cryogenic treatment at −196 °C (DCT) as well as conventional heat treatment (CHT) were carried out after carburizing process. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffractometry (XRD) were employed for microstructure characterization. The wear resistance was investigated by ball-on-disc sliding wear test on a multi-functional tribometer. The results show that the wear resistance of the experimental steel has been improved by 17% due to CT and by 25.5% due to DCT when compared to CHT. This significant improvement in wear resistance after cryogenic treatment is attributed to the microstructural changes including the finer martensitic structure, the reduction of retained austenite and the development of fine and more numerous carbides. Among these factors, the precipitation of fine carbides plays a more prominent role in enhancing wear resistance.

Microstructure and tribological evolution during laser alloying WC-12%Co and Cr3C2−25%NiCr powders on nodular iron surface

Microstructure and wear-resistant behaviors of Al2O3-TiO2 reinforced Ni-based composite coating plasma-sprayed on 6061 aluminum alloy

The article deals with the issues of increasing the fatigue strength of critical parts and components of construction machines and equipment, which are more often subjected to fatigue failure under the influence of variable complex loading. A quantitative estimate of the size of the fatigue fracture zones in the parts and joints installed in the building structures and power circuits of this construction equipment has been made. A new technique for technical diagnostics of the causes of fatigue destruction of knots of construction machines and structures is considered, revealing regularities of changes in microhardness in various zones of fatigue fractures. The results of measurements of microhardness in the zones of fatigue fractures are obtained. The systems of standard regression equations are obtained that allow one to quantify the parameters of the loading regime that led to destruction. A computational subroutine has been created that allows us to obtain analogous equations by processing the microhardness measurements of the fracture under study, and comparing them with the reference equations, give a reasonable quantitative conclusion on the causes of failure.

A κ‐carbide‐reinforced high specific Young's modulus (HSYM) steel has been developed and explored in recent years, yet its service properties remain relatively unexplored. In this work, the wear resistance of a Fe–Al–C–V HSYM steel is experimentally investigated under hot‐rolled and divorced eutectoid transformation heat‐treated conditions. Tensile tests reveal that hot‐rolled (HR) sample exhibits superior surface hardness and yield strength, but limited ductility compared with divorced eutectoid transformation (DET) sample. Three‐body impact abrasion tests indicate that HR sample consistently demonstrates a lower mass loss and an enhanced wear resistance. This improved performance is primarily attributed to its higher surface hardness of 434 ± 18.7 HV and the closely spaced lamellar carbide network, which effectively resists abrasive particle embedding and delays material spalling. Conversely, DET sample, with spheroidized/short‐rod κ‐carbides, forms a deeper work‐hardened layer owing to greater plasticity, yet shows poorer wear resistance due to lower yield strength (540 ± 7.2 MPa) and diminished resistance to abrasive penetration. These findings underscore the critical role of microstructural design in optimizing the balance between strength–ductility and wear resistance in lightweight HSYM steels for automotive applications.

Dry sliding wear behaviour of aluminum alloy 2014 microalloyed with Sn and Ag

Unveiling the effect of electron beam shock on the microstructure and wear resistance of Cr12MoV steel

Fabrication and high-temperature tribological performance of doped diamond film with B, N, and Si elements

Laser hardening is often used for hardening component segments that are subject to severe wear. Using this method, segments irradiated by laser can locally be hardened. Laser surface hardening treatment is applied on 17-4PH stainless steel and infinite chilling medium NiCr cast iron. The microstructures of the laser-treated surface layers are examined using scanning electron microscopy (SEM) or optical microscopy. The mechanical properties of the laser-treated surface are determined using nanoindentation test, and the cavitation-erosion behavior of 17-4PH stainless steel with the laser-treated surface is investigated in 3.5 wt% NaCl solution. The eroded surfaces of 17-4PH stainless steel with and without laser treatment are analyzed using SEM, and the depth data of the pits generated in the specimen surfaces are fitted into the extreme value analysis (EVA) model to predict the maximum pit depth that may occur in the material surface with a given service life. It is shown that the laser surface hardening treatment improves significantly the mechanical and cavitation-erosion performance of 17-4PH stainless steel. In the laser-treated infinite chilling medium NiCr cast iron specimen, there are three distinct zones: melting zone, transition zone and heat affected zone (HAZ). The size of the dendrite structure in the melting zone is only 1/10 to 1/30 of that in the substrate. With the microstructure refinement, the hardness and wear resistance of infinite chilling medium NiCr cast iron are improved remarkably. The field test on the surface-treated roller demonstrates that the carrying capacity of the roller increases by 50% due to the laser surface hardening, which results from the enhancement in hardness and wear resistance.

This experimental study investigates the wear resistance improvement in En 52 and 21-4N valve steels through shallow and deep cryogenic treatment using a reciprocatory friction and wear monitor as per the ASTM standard G-133. It has been observed that the wear resistance of En 52 and 21-4N has improved by 81.15% & 13.49% respectively, due to shallow cryogenic treatment, 86.54% & 22.08% respectively, due to deep cryogenic treatment, when compared to the conventional heat treatment. The microstructural study suggests that the improvement in wear resistance and hardness is attributed to the conversion of retained austenite into martensite, along with precipitation and distribution of the carbides brought in by the cryogenic treatment.