1. What is Iron Ferrite, what is it used for, and where is it found?
Well, a few definitions match your question. First, "ferrite" is the name metallurgists give to the body-centered-cubic phase of iron and its alloys. The 'body-centered-cubic' phrase refers to the way the atoms are arranged in the lattice, to distinguish it from "austenite" which is the face-centered-cubic arrangement. Generally, ferrite is a pretty pure iron- the core iron used in electrical transformers, for example, is ferritic-but there are also some stainless steels that are ferritic. These iron-chromium alloys would have 12 to 18% chromium in them, and used for expensive exhaust systems in automobiles, for example. Iron is not found in nature, as are, say, chunks of copper, but must be refined by a blast furnace or other smelting technique.
2. Which metals do not react with lithium Bromide ad why?
For solving the problem you should have the electro negativity of Li and B and calculate the difference between the two quantities, and for the next step for any metal, you should calculate the difference between its electro negativity and bromine's. Then if the result was higher than first value, one may say that this metal will react with the material otherwise it will not. However, you should have this in mind that the given procedure is true only in standard condition. However, in practice, many other factors will affect. Now I give you the calculations:
Electro negativity for Li = 1
Electro negativity for Br = 1.14
1.14 - 1 = .14
Now we consider a metal, let say Mg. Its Electro negativity is 1.2, so the difference is 1.2-1.14= .06, which is less than .14, so it will not react in standard conditions. Let say Fe, its Electro negativity is 1.8, the difference is 1.8 - 1.14 = .64 which is greater than .14, and it may react and form FeBr2.
3. What is widman statten structure?
Primary Widman statten ferrite either directly grows from the austenite grain surfaces, whereas secondary Widmanst¨atten ferrite develops from any allotriomorphic ferrite that may be present in the microstructure.
Widmanst¨atten ferrite can form at temperatures close to the Ae3 temperature and hence can occur at very low driving forces; the under cooling needed amounts to a free energy change of only 50 J mol. This is much less than required to sustain diffusion less transformation. Because Widmanst¨atten ferrite forms at low under cooling (and above the T0 temperatures),
It is thermodynamically required that the carbon is redistributed during growth.
4. Why duplex or super duplex stainless steels are welded with low heat input type electrode?
Duplex and super duplex stainless steel; but in general it's true for welding of all types of austenitic stainless steels -and you must know that we can assume duplex s. steels as austenitic s. steels cause the amount of austenite is 50% of the matrix equal to ferrite- to use a low heat input process. In addition, the reason is general in austenitic s. steels as well. That is because the weld decays. Austenitic s. steels containing about 0.1% carbon or more are often susceptible to inter granular corrosion in the weld HAZ, which is known as "Weld Decay". In these types of S .Steels the higher the heat input, the more severe the weld decay. However, here is a fact that all duplex stainless steels have a carbon content of less than 0.1%. Therefore, the severity of weld decay may be lighter, but still exists, and sensitization takes place more rapidly as the carbon content is increased.
Porosity is related to air or gas entrapment during the melting or casting process. When the metal cools and solidifies a small hole is left in the casting. Good out gassings of the melt and good foundry practice can eliminate much of this. Porosity can also be caused by lack of flow into the mold, which is a function of the alloy, superheat (temperature above the melting point), complexity of the mold and a few other factors. Another problem might be entrapment of impurities or slag in the melt. This results in a "dirty" casting. Some aluminum alloys can be particularly prone to these problems. Porosity can be eliminated by careful slag control in the melt, filters, and pour techniques.
I am not sure if the problems are particularly Indian versus British but the people who are doing the casting. I have seen excellent Indian, British, U.S., and Mexican castings as well as bad ones for these nations.
Clearly, you have some specific alloy issues possibly relating to an engineering or design problem you are working on. It appears to me then you are seeking some free consultation. I will cover some basics but you need to be talking to a local metallurgical engineer who can help with the specifics of your problem.
First, you mention two different alloys A-479 is a type 405 ferritic alloy, 11.5 - 14.5 Cr, 0.8 C, and no nickel. This single-phase BCC alloy is not heat treatable. The XM-19 alloy is a type 209 austenitic stainless steel, sometimes called Nitronic 50, 20.5 - 23.5 Cr, 0.6 C, 4 - 6 Mn, 11.5 - 13.5 Ni, plus all kinds of minor alloying elements. This stable, single-phase FCC alloy is also not heat treatable but gets its strengthening from cold work.
The primary users of pressure vessels and piping are the chemical, petroleum, and electric power industries. The classification of pressure vessels regarding the material is based on the working environment and service temperature.
For ordinary-temperature service, the ultimate strength of steels remains relatively constant over the temperature range from -30 to 345, consequently the plain carbon steels are the most commercial.
For low-temperature service, to ensure safe performance, the steel must be resistant to the initiation and propagation of a crack under all service conditions. In thick sections, plain carbon steels produced according to fine-grain practice and normalized or quenched and tempered are used for service to -45 degrees centigrade. Low-carbon high nickel steels are used for service down to -195. Austenitic chromium-nickel steels, aluminum, and special copper and aluminum-base alloys have been found to be particularly suitable for applications close to absolute zero. Because austenitic steels have a face-centered cubic (FCC) crystal structure, they retain toughness to very low temperature.
8. What is the different between ferrite percentage and ferrite number?
Ferrite Number is an arbitrary standardized value designating the ferrite content of an austenitic stainless steel weld metal. It should be used in place of percent ferrite or volume percent ferrite on a direct replacement basis.
FN has been adopted as a relative measure for quantifying ferritic content using standardized magnetic techniques. The FN approach was developed in order to reduce the large variation in ferrite levels determined on a given specimen when measured using different techniques in different laboratories. FN approximates the "volume percent ferrite" at levels below 8 FN; above this level, deviation occurs.
A number of instruments are commercially available for determining the ferrite content of welds, including the Magne gage, Severn gage, and ferrite scope.
Brass is alloy of copper and zinc, of historical and enduring importance because of its hardness and workability.
However, brass is not magnetic, the basic magnetic elements are Iron, Cobalt and Nickel and their alloys. Then there are the new ceramic materials, which exhibit magnetic capabilities.
10. Why is steel vital in the construction of an aircraft?
In the aircraft business, carbon steels provide the airframe structure, landing gear, and by alloying with nickel, chromium, and other elements it makes up most of the aircraft gas turbine engine materials. Titanium is used in some cases for the aircraft structure because it is less dense but also much more expensive.
