Browse Topic: Chromium
A new material might contribute to a reduction of the fossil fuels consumed by aircraft engines and gas turbines in the future. A research team from Karlsruhe Institute of Technology (KIT) has developed a refractory metal-based alloy with properties unparalleled to date. The novel combination of chromium, molybdenum, and silicon is ductile at ambient temperature. With its melting temperature of about 2,000 degrees Celsius, it remains stable even at high temperatures and is at the same time oxidation resistant. The results are published in the journal Nature.
A new high-temperature resistant material exhibits great potential for applications such as energy-efficient aircraft turbines. Karlsruhe Institute of Technology, Karlsruhe, Germany A new material might contribute to a reduction of the fossil fuels consumed by aircraft engines and gas turbines in the future. A research team from Karlsruhe Institute of Technology (KIT) has developed a refractory metal-based alloy with properties unparalleled to date. The novel combination of chromium, molybdenum, and silicon is ductile at ambient temperature. With its melting temperature of about 2,000 degrees Celsius, it remains stable even at high temperatures and is at the same time oxidation resistant. The results are published in the journal Nature. High-temperature-resistant metallic materials are required for aircraft engines, gas turbines, X-ray units, and many other technical applications. Refractory metals such as tungsten, molybdenum, and chromium, whose melting points are around or higher than 2,000 degrees Celsius, can be most resistant to high temperatures. Their practical application, however, has limitations: They are brittle at room temperature and, in contact with oxygen, they start to oxidize causing failure within short time already at temperatures of 600 to 700 degrees Celsius. Therefore, they can only be used under technically complex vacuum conditions - for example as X-ray rotating anodes.
With rising environmental concerns, developing lead-free solders is crucial for sustainable electronics. Traditional lead-based solders, while effective, pose health and environmental risks, prompt a shift to safer alternatives that retain reliability. Sn-9Zn alloys, when alloyed with elements such as cerium (Ce) and chromium (Cr), show enhanced mechanical and thermal properties suited for modern electronics. This study examines the effects of Ce and Cr, and their combination in Sn-9Zn solder alloy, analyzing improvements in microstructure, thermal, wettability, and hardness properties. Microstructural analysis reveals that Ce and Cr additions refine the alloy’s structure, benefiting performance. Wettability testing shows that Sn-9Zn-0.05Ce achieves the lowest wetting angle, while Sn-9Zn-0.05Ce-0.1Cr displays a balanced angle between Sn-9Zn-0.05Ce and Sn-9Zn-0.1Cr. Differential scanning calorimetry (DSC) results indicate that Sn-9Zn-0.05Ce has the lowest melting temperature, while Sn-9Zn-0.1Cr has the highest, with Ce and Cr together reducing the melting temperature by 2.83°C from the peak in Sn-9Zn-0.1Cr. Apart from this, the Vickers microhardness test reveals the highest hardness in Sn-9Zn-0.05Ce-0.1Cr with 19.62 HV, underscoring the strengthening effects of Ce and Cr. The outcomes suggest Ce and Cr alloying as a promising approach to enhance the performance of lead-free solders in eco-friendly electronics.
High-strength steel has several industrial applications such as automobile, tool and die, construction industries etc. However, it is challenging to achieve it. Various strengthening mechanisms, such as dispersion strengthening, alloying, grain boundary strengthening etc., plays a vital role in deciding the properties of the steel. At the industrial level, high-strength steel is produced by adding alloying elements such as Tungsten, Chromium, and Molybdenum in the steel matrix, increasing the high-strength steel cost. On the other hand, Wire Arc Additive manufacturing (WAAM) can produce dispersion strengthening in steel to mimic the properties of a high-strength steel matrix. The WAAM is a relatively low-cost additive manufacturing technology which uses a welding process to build up layers of material to fabricate the finished product. We have dispersed hard silicon carbide (SiC) particles in the mild steel matrix using the WAAM process in this work. SiC-dispersed steel's hardness is 28% higher than mild steel samples prepared by the WAAM process. The SEM micrograph shows the presence of dispersion of SiC in the steel matrix, which increases hardness compared to mild steel samples.
This specification covers the requirements for brush plating of zinc-nickel by electrodeposition.
Electroplating is a process whereby an object is coated with one or more relatively thin, tightly adherent layers of one or more metals. It is accomplished by placing the object to be coated on a plating rack or a fixture, or in a basket or in a rotating container in such a manner that a suitable current may flow through it, and then immersing it in a series of solutions and rinses in planned sequence. The advantage to be gained by electroplating may be considerable; broadly speaking, the process is used when it is desired to endow the basis material (selected for cost, material conservation, and physical property reasons) with surface properties it does not possess. It should be noted that although electroplating is the most widely used process for applying metals to a substrate, they may also be applied by spraying, vacuum deposition, cladding, hot dipping, chemical reduction, mechanical plating, etc. The purpose for applying an electroplate and the metals used for various applications follow.
This specification covers an aircraft-quality, low-alloy steel in the form of bars, forgings, mechanical tubing, and forging stock.
This specification covers an aircraft-quality, low-alloy steel in the form of sheet, strip, and plate.
In current scenario, there is trend to use stainless steels in place of carbon steels and aluminized carbon steels for Exhaust application. In response to changing regulatory requirements and durability performance requirements of exhaust systems, the ferritic stainless steels are proven to be best suited for the purpose. There are multiple ferritic stainless steels available as options for exhaust system. The material in an exhaust system is subject to heat, oxidation, corrosion and condensate. These environment condition demands that exhaust material should possess high temperature corrosion and oxidation resistance along with required mechanical performance such as vibration and thermo-mechanical load cycles. This work is an attempt to develop simulated test methods for corrosion and thermal environment and evaluate performance of commonly used ferritic stainless steels. The ferritic stainless steels, in this study, were subjected to corrosive media and synthetic exhaust environment. Specific test conditions with respect to chemical concentration and thermal cycles were used to simulate exhaust conditions. The results showed improvement in performance of ferritic stainless steel grades with increase in chromium content. The study also provided comparative performance of ferritic stainless steel grades at different temperatures. The relative performance derived from the study can be used to select the right exhaust stainless steel material for the exhaust system.
This specification defines limits of variation for determining acceptability of the composition of cast or wrought nickel, nickel alloy, and cobalt alloy parts and material acquired from a producer.
This specification covers an aluminum alloy in the form of sheet and plate 0.020 to 4.00 inches (0.51 to 101.60 mm), inclusive, in nominal thickness (see 8.5).
This specification covers an aluminum alloy in the form of sheet and plate 0.008 to 1.000 inch (0.20 to 25.40 mm), inclusive, in thickness, clad on two sides, supplied in the annealed (O) condition. When specified, product shall be supplied in the “as fabricated” (F) temper (see 8.6).
This specification covers an aluminum alloy in the form of sheet and plate with thickness from 0.008 to 4.000 inches (0.20 to 101.6 mm), inclusive, clad on two sides (see 8.6).
This specification covers an aluminum alloy in the form of sheet and plate 0.008 to 4.000 inches (0.20 to 101.6 mm), inclusive, in thickness (see 8.6).
This specification covers an aluminum alloy in the form of sheet clad on both sides with a different alloy for sheet thicknesses of 0.020 to 0.128 inches (0.51 to 3.25 mm), inclusive, in nominal thickness (see 8.5).
Hexavalent chromium is not a term frequently associated with engineers. Residents of Hinkley, California, however, know all about it. So do workers tasked with the labor-intensive process of depainting aircraft.
SS304 (Stainless Steel 304) is a nickel- chromium based alloy, that is extensively used for the applications like cryogenic vessels, valves, refrigerator equipment and evaporators because of its high corrosion resistance, ductility and ability to remain as solid up to a temperature of 14000 C. SS304 is one of the tough to machine materials by conventional methods of machining. Wire Electrical Discharge Machining (WEDM) facilitates the ease of machining complicated cuts with hard to machine, conductive materials where high surface finish is required. In this investigation, a study has been done on WEDM of SS304 and mainly to optimize the process parameters during the machining of SS304 by using Taguchi’s analysis. Taguchi’s DoE approach is used to plan the experimental runs and by considering the process parameters such as pulse on time, pulse off time and peak current at three different levels the experiments were conducted. The performance measures considered in present analysis are material removal rate, surface roughness and overcut. Contour plot analysis has been prepared for revealing the overall influence of process variables on desired performance measures. Analysis of Variance (ANOVA) has been used to establish the significance of independent variables on the desired dependent variables. Through this overall investigational analysis, the effect of individual process parameters on the response parameters have been studied. Stainless steel alloys are primarily applied for high temperature applications. SS304 can maintain its mechanical and chemical characteristics stable in all kinds of working environments. These materials are considered as harder materials due to these extraordinary properties. Stainless Steel 304 is most widely used nickel and chromium based alloy for number of engineering applications such as refrigerator equipments, valves, evaporator coils and cryogenic applications. SS 304 shows high ductility, corrosion resistance and excellent tribological and abrasive behaviour at higher temperatures (Ramesh Raju et al. 2019; Ramesh Raju et al. 2018; Palanisamy et al. 2021; Bagci and Seref, 2006; Kumar et al. 2009). Wire Electrical Discharge Machining (WEDM) is a superior method of modern machining processes which is also familiar as spark erosion machining process. In WEDM, the spark generation is due to the gap voltage developed that is sufficiently higher to develop the required high power spark that rises the temperature to more than 10000 degree Celsius that eventually removes the metal from the work piece as shown in the figure 1. The material removal in this WEDM process is irrespective of the hardness of the material to be machined. (Palanisamy et al. 2020; Davim, 2008; Manikandan et al. 2020; Ugrase et al. 2015; Manikandan et al. 2020; El-Hofy 2005). Taguchi’s concept is a significant one for planning the experimental trials and also adopted for single response optimization. Optimization of process parameters plays a vital role in reducing the overall cost with an improved quality. An appropriate approach also has been adopted for deriving the multi performance called GRG, which is attained by a Multi Criteria Decision Making Method called Grey Relational Approach. The method of GRA is much helpful for deriving the various combinations for attaining better multiple performance machining characteristics (Welling, 2014; Leone et al. 2011; Yang et al. 2017; Durairaj et al. 2013; Raj and Radhika, 2017; Palanisamy and Senthil, 2016; Manikandan et al. 2018). It is surmised from the available research article, that there is a demand of attention on machinability analysis of Wire Electrical Discharge Machining of harder materials. In this present explorative study, an endeavour has been considered for investigating the significance of process variables by Taguchi-Grey approach and to analyze the importance of variables using ANOVA analysis. Contour plots also developed for disclosing the prominence of input variables on desired performance measures.
Foundry industries are very much familiar and rich experience of producing ferrous castings mainly Flake Graphite (FG) and Spheroidal Graphite (SG) cast iron. Grey cast iron material is mainly used for dampening applications and spheroidal graphite cast iron is used in structural applications wherein high strength and moderate ductility is necessary to meet the functional requirements. However, both types of cast iron grades are very much suitable in terms of manufacturing in an economical way. Those grades are commercially available and being consumed in various industries like automotive, agriculture etc, High strength SG Iron grades also being manufactured by modifying the alloying elements with copper, chromium, manganese andcobalt. but it has its own limitation of reduction in elongation when moving from low to high strength SG iron material. To overcome this limitation a new cast iron developed by modifying the chemical composition. Additionally, strengthening mechanism were studied to have a linear relationship of strength and elongation even in higher strength. As an outcome, solid solution ferritic strengthened ductile SG iron developed to meet light weight design requirements. In this paper, the effect of alloying elements, strengthening mechanism, chemical, mechanical, microstructural properties, weight optimization, manufacturing challenges and validation etc, are discussed in detail.
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