The purpose of this report is to understand the failure of high strength steel wires due to the environment in which they are exposed to, this report will primarily be focusing high strength steel wires that are used in suspension bridge cables. Due to the environment that the bridge cables are exposed to their lifetime expectancy depends on the corrosion it undergoes. There are various types of corrosions that can occur such as pitting corrosion, stress corrosion and corrosion-induced cracking which it makes it all the more complex to understand corrosion of high strength steel wires(1). Due to the vast number of failures that can occur due to the environment this paper primarily focuses on hydrogen embrittlement. Hydrogen embrittlement occurs when steel is exposed to hydrogen causing it to become brittle and crack.
Hydrogen reduces load – bearing capability and reduction of ductility, there are several hydrogen sources, it can enter the material as a result of electroplating, and the main source of hydrogen in steel bridge cable wires is hydrogen gas in the atmosphere. Molecular hydrogen is dissociated, which produces atomic hydrogen that then diffuses internally and embrittle’s the metal. Hydrogen diffuses rapidly through the lattice due to its small size this is because hydrogen in the lattice exists as a monoatomic form. Dissolved hydrogen can travel along by moving dislocation in response to applied stress. On a macroscopic scale hydrogen produces a decrease in the prevalence of ductile process in comparison to fracture without hydrogen due to a decrease in stress intensity (2). Cracks grown in hydrogen embrittlement are mostly along slip planes which can be seen as striations. Hydrogen tends to accumulate in lattice, gra...
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Steven Hermosillo Professor Wallace Fire Tech 105 15 November 2015 Silver Bridge Collapse According to Wikipedia, Forty-six people were killed in the silver-bridge collapse and another nine people were injured. “The Silver Bridge was an eye-bar-chain suspension bridge built in 1928 and named for the color of its aluminum paint. The bridge connected Point Pleasant, West Virginia, and Gallipolis, Ohio, over the Ohio River” (Wikipedia). This was a highly used bridge serving thousands of cars a day before the collapse.
Hydrogen is a diatomic element that is in a gaseous form at room temperature. Its most identifying characteristic is the fact that it is highly explosive. It is the lightest element in the world, and has a lifting power of 8% more than that of helium. Hydrogen was used in airships and zeppelins for more than 20 years during the beginning of the 20th century. This practice stopped abruptly after the German airship Hindenburg disaster over New Jersey. It is used in fuel cells to create electricity, and to power cars and planes. Liquid hydrogen is mixed with liquid oxygen to form a cryogenic liquid that is burnt in Solid Rocket Boosters to power the space shuttle. Hydrogen is used to fill weather balloons because of its superb lifting power.
Titanium exhibits a variety of mechanical properties that allows it to be used in different applications. Titanium is extremely resistant to corrosion especially when in close proximity with different media such as human bone, synovial fluid and plasma. This is achieved through the use of a stable and insoluble oxide film that strongly adheres to the surface of titanium. Research has shown that titaniums resistance is considerably better than
[14] Liu, J. (2013). "Effect of diffusion annealing on interface microstructure of hot rolled high boron alloyed stainless steel composite plate". Transactions of Materials and Heat Treatment (1009-6264), 34 (4), p. 90.
Elements are the basic building blocks of matter due to the fact that they are chemically the simplest substances. Whether we can find them in the air or in our gold/silver necklaces, elements are everywhere! One essential element is hydrogen, the first element on the period table (located under Group 1 as an alkaline metal) is composed of a single proton and electron; therefore having an atomic number and atomic mass of 1 and electron configuration of 1s1. In fact, hydrogen is the lightest, simplest and most commonly found chemical element in the universe (it makes up about 90% of the universe by weight). Interestingly enough, the heavier elements on the periodic table were either made from hydrogen or other elements that were made from hydrogen. The most common isotope formed of hydrogen is protium, with 1 proton and no neutrons. Hydrogen can also exist as both positively or negatively charged. The physical form of hydrogen at room temperature is a colorless and odorless gas. Hydrogen gas is extremely flammable and because of this chemical property, it is used as fuel for the main engine of space shuttles. Hydrogen is an important element and has received a lot of recognition throughout history for its usefulness.
Chapter two of this document describes the definition of fatigue failure and summarizes the research done in the area of fatigue behavior of steel moment connections and the concept of low-cycle fatigue.
The Tacoma Narrows Bridge is perhaps the most notorious failure in the world of engineering. It collapsed on November 7, 1940 just months after its opening on July 1, 1940. It was designed by Leon Moisseiff and at its time it was the third largest suspension bridge in the world with a center span of over half a mile long. The bridge was very narrow and sleek giving it a look of grace, but this design made it very flexible in the wind. Nicknamed the "Galloping Gertie," because of its undulating behavior, the Tacoma Narrows Bridge drew the attention of motorists seeking a cheap thrill. Drivers felt that they were driving on a roller coaster, as they would disappear from sight in the trough of the wave. On the last day of the bridge's existence it gave fair warning that its destruction was eminent. Not only did it oscillate up and down, but twisted side to side in a cork screw motion. After hours of this violent motion with wind speeds reaching forty and fifty miles per hour, the bridge collapsed. With such a catastrophic failure, many people ask why such an apparently well thought out plan could have failed so badly?(This rhetorical question clearly sets up a position of inquiry-which iniates all research.) The reason for the collapse of the Tacoma Narrows Bridge is still controversial, but three theories reveal the basis of an engineering explanation. (Jason then directly asserts what he found to be a possible answer to his question.)
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.
After quenching, the heated steel will cool down. Due to the different rate of cooling, the different types of microstructure will be formed. The formation of pearlite, bainite and martensite determine the physical properties such as hardness, strength and ductility.
Automotive wires are the special wires used to connect various 12V electrical accessories in automobiles. Some of these accessories may include automotive relays, switch panels, and fuse blocks. Automotive wires are categorized into cross-linked and PVC wires depending on the type of insulation materials used during their manufacture. Let’s various types of automotive wires used in the automobile industry.
The basis for the understanding of the heat treatment of steels is the Fe-C phase diagram. Because it is well explained in earlier volumes of Metals Handbook and in many elementary textbooks, the stable iron-graphite diagram and the metastable Fe-Fe3 C diagram. The stable condition usually takes a very long time to develop, especially in the low-temperature and low-carbon range, and therefore the metastable diagram is of more interest. The Fe-C diagram shows which phases are to be expected at equilibrium for different combinations of carbon concentration and temperature. We distinguish at the low-carbon and ferrite, which can at most dissolve 0.028 wt% C at 727 oC and austenite which can dissolve 2.11 wt% C at 1148 oC. At the carbon-rich side we find cementite. Of less interest, except for highly alloyed steels, is the d-ferrite existing at the highest temperatures. Between the single-phase fields are found regions with mixtures of two phases, such as ferrite + cementite, austenite + cementite, and ferrite + austenite. At the highest temperatures, the liquid phase field can be found and below this are the two phase fields liquid + austenite, liquid + cementite, and liquid + d-ferrite. In heat treating of steels the liquid phase is always avoided. Some important boundaries at single-phase fields have been given special names. These include: the carbon content at which the minimum austenite temperature is attained is called the eutectoid carbon content. The ferrite-cementite phase mixture of this composition formed during cooling has a characteristic appearance and is called pearlite and can be treated as a microstructural entity or microconstituent. It is an aggregate of alternating ferrite and cementite particles dispersed with a ferrite matrix after extended holding close to A1. The Fe-C diagram is of experimental origin. The knowledge of the thermodynamic principles and modern thermodynamic data now permits very accurate calculations of this diagram.
In chemistry there are a lot of elements on the periodic table. One of the elements is hydrogen. Hydrogen the first element in the periodic table it is colorless, combustible and lightest of all gases. It was first artificially produced in the early 16th century by Henry Cavendish. As we know hydrogen can be used as fuel, and the fossil fuel energy has been used in many areas, but human can’t produce the fossil energy fuel by themselves, the more we use, the less we have left, so hydrogen may be used as the most common use fuel instead of gases in the future, it is not only used as fuel but also extensively used in different areas, such as industry, agriculture, medicine, and research.
Corrosion is by far the greatest concern when it comes to aging aircraft. Corrosion is a deformity that occurs at the surface and subsurface of the structure and components of aircraft. This creates a greater need for advance techniques and inspections used to detect these deformities. Some techniques talked about in this paper that are used to detect corrosion are non-destructive testing, and different scheduled inspections.
Metals possess many unique fundamental properties that make them an ideal material for use in a diverse range of applications. Many common place things know today are made from metals; bridges, utensils, vehicles of all modes of transport, contain some form of metal or metallic compound. Properties such as high tensile strength, high fracture toughness, malleability and availability are just some of the many advantages associated with metals. Metals, accompanied by their many compounds and alloys, similar properties, high and low corrosion levels, and affects, whether negative or positive, are a grand force to be reckoned with.
Annealing and tempering are not the same types of heat treatment. Annealing can be defined as heating the steel to aus...