Stainless Steel Essay
explanatory Essay
1272 words
Stainless steel, especially, Austenitic stainless steel, because of their high corrosion resistance and customizable mechanical properties has become an indispensable part of the regularly evolving modern day technology. Stainless steels of various grades find applications in numerous fields starting from the household to the nuclear reactors; from food and beverage cans to construction of different automobile parts. The formation of impervious oxide layer on the surface makes it suitable for use in adverse environments such as sea water.
The high temperature application of Austenitic Stainless Steel is somewhat limited because at higher temperatures it undergoes a phenomenon called Sensitization. According to Ghosh et al. [1], it refers to the precipitation of carbides and nitrides at the grain boundaries. Precipitation of Chromium rich carbides (Cr23C6) and nitrides at the grain boundaries result when the Austenitic stainless steel is heated and held in the temperature range of 500-8500C (773K-1123K). This precipitation of carbides taking place at the grain boundary is because of their insolubility at these temperature ranges. This leads to Chromium depreciated regions around the grain boundaries. So the change in microstructure is takes place and the regions with low Chromium contents become susceptible to Intergranular Corrosion (IGC) and Intergranular Stress Corrosion Cracking (Alvarez et al.) [1, 2]. Along with carbides and nitrides there is formation of chi phase. The chi phase, which is a stable intermetallic compound, consists of Fe, Cr, and Mo of type M18C. Some studies reveal that sensitization may lead to formation of Martensite. In addition to the altered microstructure, mechanical properties of the Austenitic Stain...
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...rmination
To obtain a detailed knowledge on the effect of Sensitization on the hardness of the samples, two kinds of hardness determination tests were performed.
(a) Micro Hardness
(b) Macro Hardness
(a) Micro Hardness
In order to perform the micro hardness test on the samples, they were first roughly polished using belt grinder. Then they were polished with the Emery papers as described in previous descriptions so as to obtain flat surfaces and to avoid anomalies in the results.
The micro hardness of the prepared samples were obtained by using a Vickers Micro hardness Tester (Model : Leco LV 700, USA). 5 readings were taken for each sample to calculate the average hardness. An indentation load of 5gf was used. After calculating the average hardness for each sample, mean variance and standard deviation (S.D.) was calculated to check the consistency of the data.
In this essay, the author
- Explains that the objective of this investigation is to study the effect of sensitization on the mechanical and microstructural properties of a nonconventional stainless steel.
- Explains that x12crmnnin17-7-5, a special grade of non-conventional austenitic stainless steel, was selected for this investigation.
- Explains that thermo electron corporation limited, switzerland provided the chemical composition of the chosen sample determined with help of optical emission spectrometer.
- Explains that the sample was subjected to heat treatment which included solution annealing to dissolve precipitated phases, followed by water quenching.
- Describes how an optical microscope was used to reveal the microstructures of the prepared samples. the samples were put under the microscope lens and images were captured at various magnifications.
- Explains that two kinds of hardness determination tests were performed to obtain a detailed knowledge on the effect of sensitization on samples.
- Explains that austenitic stainless steel has become an indispensable part of the constantly evolving modern day technology.
- Describes how the samples were polished with a belt grinder and etched with aqua regia. the fineness of the papers increases with their grade.
- Explains how the liner intercept method was applied to determine the size of the grains of nonconventional stainless steel samples. the number of grains cut by a line was counted.
- Explains how samples were polished using belt grinder, then polished with emery papers to avoid anomalies in the results. the micro hardness of the samples was calculated using a vickers micro hardness tester.
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- Stainless Steel Essayexplanatory essayI. INTRODUCTION Martensitic stainless steels have good mechanical strength and moderate corrosion resistant. Because of their excellent corrosion resistance and mechanical strength, martensitic stainless steels are used for manufacturing the steam turbine blades, heat exchangers, automotive components and structures, petrochemical & process piping. Properties of martensitic stainless steel can be changed by the heat treatment. Increasing productivity of any welding process while maintaining or even improving the weld quality has been the task of researchers in the field of development of welding processes.
In this essay, the author
- Explains how the experimentation section discusses the procedural steps that were used for experimental investigation in a systematic manner so that the formulated objectives of this work could be achieved.
- Explains that martensitic stainless steel plates were cut to length from the flats, and metallurgically compatible filler wire aisi 410 ss was used to fill the groove volume.
- Explains that pre-cleaning the surface of the base plates and groove edges was done so that dust, oil, rust and other unwanted particles could be removed from the weld area.
- Explains that the root pass was made with the help of aisi 304l ss solid filler wire in each joint and the welding parameters used were kept constant.
- Analyzes the effect of post weld heat treatment on the mechanical performance of the welded joint. the specimens were heated at 740°c for 90min.
- Explains the details of the mechanical testing of different welded samples in as well as post weld heat treatment condition.
- Presents the results of the experimentation, mechanical testing (tensile test and impact test) of different welded specimens.
- Describes the results of the transverse tensile testing of different welded specimens according to astm e-08 (tension testing of metallic materials).
- Explains that low heat input and pwht improve the tensile performance of these joints, but this strength increase occurs at the expense of reduced ductility.
- Explains that the charpy v-notch impact test was conducted at room temperature. specimens were taken from each welded plate and prepared according to astm e-23 standard.
- Explains that the maximum cvn value was 127 joules recorded, which is possessed by low heat input welded specimen in post weld heat treatment condition.
- Explains that the weld joint made using the low heat input possessed the maximum ultimate tensile strength (791.56 mpa).
- Explains that in the present experiment work, maximum uts increased by 38.11 mpa for the joints fabricated with low heat input and subjected to post weld heat treatment.
- Explains that the maximum cvn value in welded condition of low heat input combination is 115 joule and it is increased with the post weld heat treatment.
- Compares the joints welded with two different heat inputs and concludes that the ultimate tensile strength (uts) and impact toughness decreases with increases in heat.
- Explains that martensitic stainless steels have good mechanical strength and moderate corrosion resistant properties. the heat input rate is one of the most important variables in fusion welding.
1375 wordsRead More - Stainless Steel Essayexplanatory essayStainless steel is a type of alloy that has a very strong lattice structure (an arrangement/ shape of the crystals or other objects) which in some case can be more beneficial than others depending on the type of application it may be used for. In many cases this structure will make the material more suited to being used in engineering applications such as tools for instance a hammer (stainless steel alloys) , also they can be used for gears, engines, electrical motors and hydraulic systems because the structure makes the material so strong. So when the arrangement of the structure is as above it makes the overall material even stronger which makes it a good for all the applications stated above. I believe its strength and durability are its main properties as these are commonly needed in the engineering industry, although it is also very well known to be used for its corrosion resistance as it is resistant to many types of corrosion. It is used for these properties because the components such as gears need to be strong in order to keep transferring and altering the rotary motion and torque exhibited in the machine that it may be used in, durable to withstand any loads or pressure put onto it and also corrosion resistance to give the components a bigger life span and increase its rate of work throughout its required use.
In this essay, the author
- Explains that stainless steel has a strong lattice structure that makes it more suited to engineering applications such as tools, engines, electrical motors, and hydraulic systems.
- Explains that polymer-polyethylene is partially crystalline and amorphous. it can be moulded or extruded into shapes such as pipes.
- Explains the properties of alumina, such as strength, corrosion resistance and wear resistance, which makes it important in engineering. aluminium oxide is the second hardest mineral after diamond and is non-reactive.
- Explains that carbon-fibre is made up of layers of fibrous composite materials, bonded together in minuscule crystals, and has a high strength to weight ratio.
- Explains that nitinol is an alloy of nickel and titanium. it can be used in engines and couplings in aerospace applications due to its useful properties.
1180 wordsRead More - Micro Hardness Test Essayexplanatory essaySurface roughness measurement is carried out using a portable surface roughness tester (Fig. 11). The sampling length is around 0.8 mm with a velocity of 0.5 mm/s. Table 2 gives the surface roughness values. It is noticed that the values are consistent across grain sizes.
In this essay, the author
- Explains that a microhardness measurement is done using the mitutoyo micro hardness tester (load range 10 g to 2 kg) for two samples.
- Explains that surface roughness measurement is carried out using a portable surface-roughness tester. the sampling length is around 0.8 mm and the values are consistent across grain sizes.
- Explains that the micro extrusion experiments are conducted without lubrication at room temperature using the testing platform. the grain size effect on deformation load plays a significant role.
- Explains the force-displacement curves for the experiments with pure copper billet are shown in fig. 13.
- Explains that the relatively coarse grain structure leads to non uniform material flow and lack of repeatability during extrusion. to investigate the effect of grain refinement, refined copper is produced by heat treatment process.
- Explains that the difference of deformation load with different grain sizes becomes significant in the stable forward extrusion phase. the anisotropy grain properties become significant when only a few grains flow into the micro sized cavity.
- Explains that the grain size of the material can be varied by heat treatment process. the original microstructure of copper and aluminum is shown in fig.
778 wordsRead More - The Benefits and Manufacturing of Duplex Stainless Steelexplanatory essayDuplex stainless steels is a combination of many of the beneficial properties of ferritic and austenitic steels. First duplex steel grades had a great performance characteristics as well as limitations. The metallurgical processes at that time were not suitable for producing grades with the right austenite-ferrite balance. These early duplex steels were also high in carbon content because of the unavailability of efficient decarburization techniques. Because of these limitations the products using this materials were limited to specific applications. (Alvares-Armas, 2008)
In this essay, the author
- Explains the processing and manufacturing of super duplex is the same as the austenitic steels, with the difference in microstructure and metallurgy.
- Explains how the raw materials iron ore, chromium, silicon, nickel, etc. are melted together according to the required quantity in a furnace and the liquidized mixture is cast into semi-finished forms.
- Explains that once the steel is semi-finished it is sent to the forming operations. the first operation is hot rolling where heated steel passed through heavy rolls.
- Describes cold rolling in combination with annealing in a controlled atmosphere furnace, by grinding, or by buffing.
- Explains that the first cast of duplex was made at avesta in sweden in 1930. the evolution in steel making techniques affected mainly to this take off.
- Explains the process of annealing, wherein steel is heated and cooled under controlled conditions to relieve stresses and soften the metal. lower aging temperatures produce high strength with low fracture toughness.
- Explains how various processes can be used to remove scale from steel. pickling, elctrocleaning, hot rolling, forging, and extruding are examples.
- Explains that cutting is done by mechanical cutters and various techniques are used to cut the super duplex steels.
1015 wordsRead More - Metallurgy Essayexplanatory essayIntroduction Metallurgy is the field of materials science and material engineering that studies the physical and chemical behaviour of metallic elements, their microstructure compounds and their mixtures, which are mostly known as alloy. Metallurgy can be refers as the technology of metals where science is applied to the production of metals, and the engineering of metal components for the uses of products for consumers and manufacturers. Metals are widely use in industrial, economic growth and most importantly our daily life. Metals can be found in our car (steel), cell phones (gold, tin), computers (mercury, lithium), electrical wires (copper) and soda can (aluminium). But what is the prime factor that really determines the quality of metals?
In this essay, the author
- Explains that steels owe their ascendance of the field of engineering materials to their ability to respond to heat treatment and provide congruous properties at economic cost on an engenderment scale.
- Explains that heat treatment is a process using the controlled application of heat to change the physical and chemical properties of materials. glasses can also be heat treated.
- Explains that annealing and tempering are not the same types of heat treatment.
- Explains process annealing, also known as subcritical, in-process, or intermediate, is applied in softening metals or to restore ductility to product after cold working by heating the metal below the austenite phase.
- Explains the process of annealing, which involves heating the steel to 30-50 degrees c above the critical temperature of steel and maintaining the temperature for a specified period.
- Explains that every time a piece of metal is used or worked, it absorbed and accumulates stress and becomes harder. solidification processes result in both micro and macro segregation of the alloying elements present.
- Explains that different kinds of annealing treatments are widely used in commercial practice.
- Explains that hot and cold rolled steel sheets and strips are annealed to relieve the stresses begot during rolling or cold working, and also to soften the material for ensuing fabrication.
- Explains that annealing of mach-inability depends on the microstructure and hardness of the steel. the presence of coarse pearlite enhances the machinability of medium carbon steels.
- Explains that forgings are commonly annealed to improve their mach-inability and to acquire the desired microstructure.
- Explains the importance of maintaining proper temperatures when tempering a work piece to achieve the perfect result.
- Explains that the structure of steel obtained after hardening is not suitable for engineering applications.
- Explains that the formation of martensite from austenite by quenching produces large internal stresses in the hardened steel.
- Explains that martensite obtained after hardening is extremely brittle and results in cracking of the tools.
- Explains that the tempered process introduced some transformations in the structure and properties of steel.
- Explains that internal stresses in steel caused by hardening process are due to these two reasons.
- Describes the rapid decrease in temperature of the specimen, resulting in what is known as thermal stresses.
- Explains that martensite obtained after hardening is quite brittle and not acceptable in structural and tool steels. ductility and toughness of hardened steel can be enhanced by tempering at a successively higher temperature.
- Explains that during tempering, steel's hardness is continuously reduced, and internal stresses are relieved. gradual decrease is observed at 350°c.
- Explains that blacksmiths temper steel so that it will not break easily. different implements are tempered to different colours, depending on how much carbon there is in the steel.
- Explains that tempered glass is a type of safety glass processed through controlled thermal treatments to increase its toughness.
- Explains tempering is a process of heating and cooling chocolate to form stable crystals so that it can be used for coating or dipping purposes.
- Explains that metallurgy is the field of materials science and material engineering that studies the physical and chemical behaviour of metallic elements, their microstructure compounds, and their mixtures.
- Explains that normalization is an annealing process applied to ferrous alloys to give the material a homogeneous fine grained structure and make it less brittle.
- Explains that annealing involves the diffusion of atoms within a solid material to facilitate carburization.
- Explains that full annealing is the process of slowly raising the temperature for about 50 oc above the austenitic temperature line a3 or line acm in the case of hypo-eutectoid steels.
- Explains quenching is a subcritical heat-treating process used to improve the toughness of quench-hardened steels.
- Explains the process of tempering, wherein the steel is heated to a specific temperature until austenization occurs, which results in homogeneous solution of austenite.
- Explains that the proper tempering temperature for a particular steel depends on the composition of the steel and the desired properties.
- Explains the structure obtained after hardening consists of reserved austenite and martensite, which are meta-stable and will change to a more stable phase with time.
- Explains the increase in volume of the specimen due to changes of austenite to martensite. internal stresses are increased for higher austenitizing temperatures and higher cooling rates.
- Explains that heat treatment of steel is a common practice among material science engineers that helps control the properties of the steel such as hardness, strength, and ductility.
- Explains that there are three kinds of heat treatment processes: softening, harden, and thermo-chemical processes. they explain that the rate of cooling from the austenite phase is determinant of final structure and properties.
3146 wordsRead More - Stainless Steel Industry Analysisexplanatory essayStainless steel has been on high preference among consumers since ages. Due to a number of advantages that it has, it is used for the manufacture of a wide range of products, including furniture. Be it in furniture, home décor, kitchen appliances, bathroom, bedroom, or other purposes, stainless steel has a lot to offer to its consumers.
In this essay, the author
- Explains that stainless steel has been on high preference among consumers since ages due to a number of advantages that it has.
- Explains that manufacturers target using stainless steel for the manufacture of different products, such as chairs, tables, desks, sink benches, cabinets, dining, beds, office furniture, etc.
- Explains that stainless steel is highly resistant to corrosion, which makes it extremely suitable for furniture products.
- Explains that the manufacturing of furniture using stainless steel is easy and convenient to achieve, as the metal can be easily curt and designed.
- Explains that stainless steel furniture has been used in early times and is still being used for its multiple advantages.
- Explains that stainless steel furniture is suitable for the modern décor of a house, with low maintenance costs and efforts adding to the attractiveness of the products.
- Explains that stainless steel furniture is highly cost-effective and perfect items to furnish a house, office, restaurant, school, or residential or commercial buildings.
499 wordsRead More - Feldspar And Olivine Essaycomparative essayFor instance, olivine (Mohs 6.5-7.0) is harder than feldspar (Mohs 6.0-6.5) [2]. For this reason, feldspar and olivine are not used together in abrasive applications, even though their properties are similar. This is mostly because olivine is harder, has a higher specific gravity and its sharper particles make it more suitable for rapid, powerful cleaning and cutting action. Feldspar on the other hand, is softer and lighter, making it perfect for polishing and more delicate cleaning work, such as personal ornaments and fragile artifacts.
In this essay, the author
- Explains that feldspar and olivine are two silicate minerals commonly found on the earth's surface. both minerals are anhydrous, since they contain no water in their chemical structure.
- Explains the crystalline structure of potassium feldspar (kalsi3o8), which consists of corners that share alo4 and sio4. these tetrahedrons contain either an aluminum or a silicon atom.
- Explains that olivine and feldspar are both widely used as abrasive minerals. they share these properties in different degrees.
- Explains that olivine and feldspar are not used together in abrasive applications, even though their properties are similar.
- Explains that feldspar and olivine are naturally occurring silicates, which are a secure substitute for silica sand as cleaning agents. the sharpness of the particles produced by angular shapes guarantees rapid and efficient cleaning.
- Compares the origins of feldspar and olivine, stating that the two minerals are found and extracted from solid rocks.
- Explains the mining method employed in the extraction of olivine is underground mining, and feldspar is extracted through conventional open-pit mining.
- Explains that a method of chemical and thermal extraction is commonly used for olivine. the ore is combined with concentrated sulfuric acid and heated to 250 degrees celsius for approximately 7.5 hours.
- Concludes that both feldspar and olivine are chemically separated in industrial scales.
767 wordsRead More - Hastelloysexplanatory essayIf we take a look at C-type alloys we see that Stainless Steel fails more often than Hastelloys® due to pitting and crevice corrosion as well as from general corrosion (see figure 1). The table below (figure 1) shows how the Critical Crevice Temperature and the Critical Pitting Temperature of some Hastelloys® and types of Stainless Steel. Hastelloy® C-22 alloy has a Critical Pitting Temperature greater than 140˚C whereas stainless steel type 316L only has a Critical Pitting Temperature of 15˚C. This shows that C-22 is a far better at resisting corrosion at higher temperatures than its Stainless Steel counterparts. The same applies to C-276; which is due to them containing a higher composition of carbon and molybdenum than that of Stainless Steel, Mild Steel and Iron.
In this essay, the author
- Describes the three main sub-groups of corrosion resistant alloys: b-alloys, c-allies, and g-allies.
- Explains that stainless steel fails more often than hastelloys® due to pitting and crevice corrosion as well as from general corrosion.
- Explains that c-22hs has double the yield strength and is the most widely used alloy in industry. c-276 hastelloy® is popular due to its strong resistant to chlorine.
- Explains that b-group alloys perform well in non-oxidizing environments. b-3 can withstand corrosion of hcl in a wide variety of concentrations and temperatures.
- Explains that the hastelloy® bc-1 is a hybrid alloy, which combines the characteristics of both c and b group alloys.
- Explains that g-group alloys have a high composition of chromium, which means they have brilliant corrosion resistance in strong oxidizing environments.
- Explains that g-35 is resistant to caustic de-alloying. the hastelloy® n alloy is a nickel-based alloy, which has good oxidation resistance to mainly hot fluoride salts.
- Explains that all the corrosion resistant hastelloys® have great resistance to both localized and uniform corrosion attack and excellent stress corrosion cracking resistance.
- Explains that hastelloys® have low carbon contents, which reduces the carbide precipitation during welding. high chromium compositions are used in strong oxidizing mediums.
- Explains that most information came from their company website. csi alloys, about c-22 -> advantages.
688 wordsRead More - Chromiteexplanatory essayOf the many ores that contain chromium, chromite is the only one that has commercial use. Chromium has a wide range of applications in metallurgical and chemical processes. When used in the production of iron, steel and other alloys, chromite will enhance the hardness and the ability to resist the effects of corrosion and oxidation. Due to these properties, it is a key component in the making of stainless steel. In the automotive and heavy industrial sectors, refractory chromite is used in its granular form to make ferrous and non-ferrous castings. The chromite sands derive their high refractoriness from low wettability and a good chemical stability. With a melting point of 2150 ºC and low thermal expansion, the bloating caused by the oxidation of the FeO compounds helps seal the moldings. In addition, this ore’s high density and thermal conductivity promotes the rapid solidification of the castings.
In this essay, the author
- Explains that chromite is an iron-chromium oxide with a chemical formula corresponding to fecr2o4.
- Explains that chromite has a wide range of applications in metallurgical and chemical processes.
- Explains that 94% of the world's production of chromite is smelted into ferrochromium alloys, while japan, the u.s., germany, and india account for the remainder.
- Explains that chromite ore is classified into general grades associated with end use. the refractory industry uses concentrates with less than 40% cr2o3.
- Explains that zircon is an anhydrous silicate mineral with the nesosilicate subclass. its chemical formula is zrsio4.
- Explains that zircon ore is valuable to many industries because of its high melting point and excellent chemical properties.
- Describes zirconia refractories as crucibles for melting platinum, palladium, and other metals. it is an integral part of the construction of reactors and can be implemented as furnace liner.
- Describes how the industry transforms zirconium oxide by molding the powder-like substance and roasting it at 1700°–2200°c.
962 wordsRead More - Choosing the Best Folding Knifeexplanatory essay...t's generally seen as beneficial because they are more resistant to the wear and tear of frequent use. They're resistant to rust and water damage, and they're easy to sharpen. However, they lose their edge quite frequently. Despite the name, stainless steel is actually susceptible to stains.
In this essay, the author
- Explains that folding knives can be extremely useful in emergency situations and everyday occurrences, but you need to know how to choose the best folding knife for your needs.
- Explains that knives come in so many styles, designs, and types that it can be confusing to know which one to need. focusing on how many blades or tools you will need on your knife should be the first aspect to think about.
- Explains that single-blade knives are the most common form of folding knife. they are stronger and more durable than multi-blade knives since they focus their entire design on one blade instead of multiple blades or tools.
- Explains that multi-blade knives are useful for people who intend to use them for a wide range of purposes. the smaller knives can fit in tight spaces, while the larger blades can be used for cutting small branches, cutting meat, carving and more.
- Explains that the most important part of any knife is the edge. having a good edge is what makes your knife so useful in various situations.
- Explains the most common type of blade, the straight edge, which provides precision, control, and ease of use. they are especially useful as self-defense, but don't have sawing function.
- Explains folding knives range from tiny knives that you could put on a keychain to large knives roughly the size of hunting knives. the sizes also have several advantages and disadvantages.
- Explains that small blades are common for people who just want a quick pocket knife for regular use, but they're usually not very durable or strong.
- Explains that medium blades falls between three and four inches long, and they're the most common type of folding knife.
- Explains that large blades are any knives over four inches long. they're useful for rough purposes like regular hunting, camping, or working in the outdoors, but bulky for everyday use around the house.
- Explains that folding knives usually come in two types of steel; stainless and carbon. both types are quite similar, but stainless steel has more chromium than carbon steel.
- Explains that stainless steel products are often boasted for many products, but knives are generally seen as beneficial because they're resistant to wear and tear, are easy to sharpen, and are susceptible to stains.
- Explains that carbon blades are tougher than stainless steel, but they are highly susceptible to rust and stains. they're also more difficult to sharpen.
- Explains that choosing the best folding knife depends on your preferences and intentions for the knife's use. compare various knives to get a good understanding of what you're looking for, and remember quality is one of the most important factors in your decision.
- Explains that these knives are the most versatile as they provide the user with a variety of tools such as corkscrews, can openers and screwdrivers alongside the knife. the downside is that there's little focus on the actual knife and the complicated design makes them weaker.
- Recommends purchasing a combo edge, which is half straight and half serrated, if you can't decide between the two.
837 wordsRead More