Process Decarburization Prior to the decarburization step, one more step should be taken into consideration: de-siliconization, which is a very important factor for refractory lining and further refinement. The decarburization step is controlled by ratios of oxygen to argon or nitrogen to remove the carbon from the metal bath. The ratios can be done in any number of phases to facilitate the reaction. The stages of blowing remove carbon by the combination of oxygen and carbon forming CO gas. The burning of carbon increases the bath temperature.
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Process Decarburization Prior to the decarburization step, one more step should be taken into consideration: de-siliconization, which is a very important factor for refractory lining and further refinement.
The decarburization step is controlled by ratios of oxygen to argon or nitrogen to remove the carbon from the metal bath. The ratios can be done in any number of phases to facilitate the reaction. The stages of blowing remove carbon by the combination of oxygen and carbon forming CO gas. The burning of carbon increases the bath temperature. Reduction After a desired carbon and temperature level have been reached the process moves to reduction.
Reduction recovers the oxidized elements such as chromium from the slag. To achieve this, alloy additions are made with elements that have a higher affinity for oxygen than chromium, using either a silicon alloy or aluminum.
The reduction mix also includes lime CaO and fluorspar CaF2. The addition of lime and fluorspar help with driving the reduction of Cr2O3 and managing the slag, keeping the slag fluid and volume small. Desulfurization Desulfurization is achieved by having a high lime concentration in the slag and a low oxygen activity in the metal bath. Also, aluminum or silicon may be added to remove oxygen. Other trimming alloy additions might be added at the end of the step. After sulfur levels have been achieved the slag is removed from the AOD vessel and the metal bath is ready for tapping.
The tapped bath is then either sent to a stir station for further chemistry trimming or to a caster for casting. Specific types of stainless steel often designated by a three digit number, e. Smelting is a process of applying heat to ore in order to extract a base metal. It is a form of extractive metallurgy. It is used to extract many metals from their ores, including silver, iron, copper, and other base metals. Smelting uses heat and a chemical reducing agent to decompose the ore, driving off other elements as gases or slag and leaving the metal base behind.
The reducing agent is commonly a source of carbon, such as coke—or, in earlier times, charcoal. In steelmaking, impurities such as nitrogen, silicon, phosphorus, sulfur and excess carbon are removed from the sourced iron, and alloying elements such as manganese, nickel, chromium, carbon and vanadium are added to produce different grades of steel. Limiting dissolved gases such as nitrogen and oxygen and entrained impurities in the steel is also important to ensure the quality of the products cast from the liquid steel.
A period 3 element is one of the chemical elements in the third row of the periodic table of the chemical elements. The periodic table is laid out in rows to illustrate recurring periodic trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when the periodic table skips a row and a chemical behaviour begins to repeat, meaning that elements with similar behavior fall into the same vertical columns. The third period contains eight elements: sodium, magnesium, aluminium, silicon, phosphorus, sulfur, chlorine, and argon.
The first two, sodium and magnesium, are members of the s-block of the periodic table, while the others are members of the p-block. All of the period 3 elements occur in nature and have at least one stable isotope. Brazing is a metal-joining process in which two or more metal items are joined together by melting and flowing a filler metal into the joint, the filler metal having a lower melting point than the adjoining metal.
Basic oxygen steelmaking, also known as Linz—Donawitz-steelmaking or the oxygen converter process is a method of primary steelmaking in which carbon-rich molten pig iron is made into steel. Blowing oxygen through molten pig iron lowers the carbon content of the alloy and changes it into low-carbon steel. The process is known as basic because fluxes of burnt lime or dolomite, which are chemical bases, are added to promote the removal of impurities and protect the lining of the converter.
An electric arc furnace EAF is a furnace that heats charged material by means of an electric arc. Gas tungsten arc welding GTAW , also known as tungsten inert gas TIG welding, is an arc welding process that uses a non-consumable tungsten electrode to produce the weld.
The weld area and electrode is protected from oxidation or other atmospheric contamination by an inert shielding gas, and a filler metal is normally used, though some welds, known as autogenous welds, do not require it. When helium is used, this is known as heliarc welding. A constant-current welding power supply produces electrical energy, which is conducted across the arc through a column of highly ionized gas and metal vapors known as a plasma.
Pyrometallurgy is a branch of extractive metallurgy. It consists of the thermal treatment of minerals and metallurgical ores and concentrates to bring about physical and chemical transformations in the materials to enable recovery of valuable metals. Pyrometallurgical treatment may produce products able to be sold such as pure metals, or intermediate compounds or alloys, suitable as feed for further processing.
Examples of elements extracted by pyrometallurgical processes include the oxides of less reactive elements like iron, copper, zinc, chromium, tin, and manganese. Shielding gases are inert or semi-inert gases that are commonly used in several welding processes, most notably gas metal arc welding and gas tungsten arc welding.
Their purpose is to protect the weld area from oxygen, and water vapour. Depending on the materials being welded, these atmospheric gases can reduce the quality of the weld or make the welding more difficult.
Other arc welding processes use alternative methods of protecting the weld from the atmosphere as well — shielded metal arc welding, for example, uses an electrode covered in a flux that produces carbon dioxide when consumed, a semi-inert gas that is an acceptable shielding gas for welding steel.
Decarburization is the process opposite to carburization, namely the reduction of carbon content. The production of this alloy results in a grayish silver crystalline solid that can be crushed into a powder called "ferrovanadium dust". Ferrovanadium is a universal hardener, strengthener and anti-corrosive additive for steels like high-strength low-alloy steel, tool steels, as well as other ferrous-based products. It has significant advantages over both iron and vanadium individually.
Ferrovanadium is used as an additive to improve the qualities of ferrous alloys. One such use is to improve corrosion resistance to alkaline reagents as well as sulfuric and hydrochloric acids. It is also used to improve the tensile strength to weight ratio of the material. One application of such steels is in the chemical processing industry for high pressure high throughput fluid handling systems dealing with industrial scale sulfuric acid production.
It is also commonly used for hand tools e. At standard conditions it exists as a gray solid. It is extremely hard and corrosion resistant. It is also a refractory compound, which means that it retains its strength at high temperatures as well. These properties make it useful as an additive to metal alloys. When chromium carbide crystals are integrated into the surface of a metal it improves the wear resistance and corrosion resistance of the metal, and maintains these properties at elevated temperatures.
The hardest and most commonly used composition for this purpose is Cr3C2. Selective leaching, also called dealloying, demetalification, parting and selective corrosion, is a corrosion type in some solid solution alloys, when in suitable conditions a component of the alloys is preferentially leached from the material. The less noble metal is removed from the alloy by a microscopic-scale galvanic corrosion mechanism.
The most susceptible alloys are the ones containing metals with high distance between each other in the galvanic series, e. The elements most typically undergoing selective removal are zinc, aluminium, iron, cobalt, chromium, and others. Alloy steel is steel that is alloyed with a variety of elements in total amounts between 1. Alloy steels are broken down into two groups: low alloy steels and high alloy steels.
The difference between the two is disputed. Smith and Hashemi define the difference at 4. Most commonly, the phrase "alloy steel" refers to low-alloy steels. Deoxidization is a method used in metallurgy to remove the oxygen content during steel manufacturing. In contrast, antioxidants are used for stabilization, such as in the storage of food. Deoxidation is important in the steelmaking process as oxygen is often detrimental to the quality of steel produced. Deoxidization is mainly achieved by adding a separate chemical species to neutralize the effects of oxygen or by directly removing the oxygen.
Glass-to-metal seals are a very important element of the construction of vacuum tubes, electric discharge tubes, incandescent light bulbs, glass encapsulated semiconductor diodes, reed switches, pressure tight glass windows in metal cases, and metal or ceramic packages of electronic components. Cobalt-chrome or cobalt-chromium CoCr is a metal alloy of cobalt and chromium. Cobalt-chrome has a very high specific strength and is commonly used in gas turbines, dental implants, and orthopedic implants.
The salt extraction process is an electrolytic method which may be used to extract valuable metals from slag, low-grade ores, or other materials by using molten salts. This method was developed by S. Seetharaman, O. Grinder, L. Teng and X.
Argon oxygen decarburization
Decarburization[ edit ] Prior to the decarburization step, one more step should be taken into consideration: de-siliconization, which is a very important factor for refractory lining and further refinement. The decarburization step is controlled by ratios of oxygen to argon or nitrogen to remove the carbon from the metal bath. The ratios can be done in any number of phases to facilitate the reaction. The stages of blowing remove carbon by the combination of oxygen and carbon forming CO gas. The burning of carbon increases the bath temperature. Reduction[ edit ] After a desired carbon and temperature level have been reached the process moves to reduction.