began to consider an alloy of iron with other chemical compounds.Among the components of the composition, is present in an amount of carbon is 2.14%.Thanks to his presence iron alloys acquire their strength.The share of steel is 75500-77500 N / m.The alloy composition may sometimes contain the alloying elements.Specific heat of steel at 20 ° C measured at 460 J / (kg * ° C), or 110 cal / (kg * ° C).
Classification
There are various options by which characterized the material in question.For example, steel is the tool and the structural.High-speed alloy is considered to be a type of tool.There are also differences in accordance with the chemical composition.Depending on what elements are present in the alloy, and carbon doped separated.Also accepted classification level of carbon concentration.So, there are three types of alloys:
1. Low carbon.It carbon content of 0.25%.
2. Steel Medium.In this alloy, carbon about 0.25-0.6%.
3. High-carbon steel.In this alloy, there is about 0.6-2% carbon.
Similarly classified and alloy steel for the percentage of alloying elements:
1. The low alloy steel containing up to 4%.
2. In srednelegirovannoj alloy is present up to 11%.
3. High-alloy steel.It contains more than 11%.
steel produced by different methods and with the use of special technologies.Depending on a particular process in the alloy composition contains different metallic inclusions.This indicator has an impact on the share of steel.Classifying alloys in the number of impurities are distinguished:
1. Mixtures of ordinary quality.
2. Quality.
3. High.
4. Specially quality.
There is also a classification in accordance with the structural composition of the material.For example, manufactured ferritic, bainitic, austenitic, pearlitic and martensitic alloys.Undoubtedly, the structural composition affects the share of steel.Alloys are also divided into two-phase and multiphase.It depends on the presence of phases in the structure.Also alloys are classified according to the nature and degree of hardening of deoxidation.So, there is a quiet, semi-killed and rimmed steel.
methods
steel production as a raw material for the manufacture of cast steel is used.The presence of large amounts of carbon, phosphorus and sulfur in its composition makes it brittle and fragile.For processing one material to another is necessary to reduce the content of these substances to the required concentration.When this change and the specific weight of steel, and its properties.One or another method of manufacturing the alloys suggests different ways of oxidation of carbon in the iron.The most commonly used:
1. Open-hearth method of steel production.It should be noted that this option recently badly competes with other methods.
2. converter method.Today, most types of steel products produced using this technology.
3. Electrothermal - one of the most advanced technological methods for producing steel.As a result of the material produced is characterized by very high quality.
converter method
Using this technology the way, the excess iron, phosphorus and sulfur is oxidized with oxygen.Implemented by blowing pressurized through the molten material in a special oven.It is called a converter.This stove has the shape of a pear.In the inner part - lining with refractory bricks.This oven has a high mobility: can be rotated 360 degrees.The capacity of the converter about 60 tons.For the lining used, as a rule, two types of materials:
1. Dinas - it includes SiO2, which has acidic properties.
2. Dolomite mass - MgO and CaO.It was obtained from material dolomite MgCO3 * CaCO3, have basic properties.
Because of different materials for the lining of the converting furnace is divided into the Thomas and Bessemer.Air is blown under pressure covering the entire area of the metal.It should be noted that the processes occurring in the furnace, have a duration of no more than 20 minutes.Duration of the material in the converter affects the heat capacity of the steel.An alloy which is produced in the converter furnaces, often contains large amounts of iron monoxide.That is why the material is often of low quality is obtained.Open-hearth furnace
This method of processing iron obsolete.Sure, using a few backward technologies in the processing of significantly reduced quality of the material, changing its characteristics (the heat capacity of steel and others).Open-hearth furnace is a big melting bath.It is covered with vault of refractory bricks, heat exchangers and chambers.These compartments are designed to heat the combustible gas and air.They are filled with a nozzle brick (refractory).The flow of hot gas and air is blown into the furnace through the third and fourth heat exchanger.A first and second in the meantime heat from flue gases.After a sufficient rise in temperature the whole process is going in the opposite direction.
electrothermal method
This method has several advantages over open-hearth and converter.Electromechanical method allows you to change the chemical composition of the resulting steel.This mixture is obtained after the conversion process is very high quality.Due to the limited access of air is reduced in an electric iron monoxide.He is known to its impurities contaminate the steel.And this, in turn, has a significant impact on its quality.The electric furnace temperature does not drop below 2000 ° C.Thus, contaminants such as sulfur and phosphorus, are completely removed from the pig iron.
method of operation of the furnace
electrothermal furnace, due to its high temperature alloy steel allow using refractory metals.These include, in particular, tungsten and molybdenum.Of arc provides a high-quality mix: the specific heat of steel, as well as its quality characteristics - at the highest level.But, unfortunately, these furnaces consume large amounts of electrical energy (up to 800 kWh per ton of raw material).Electric capacity can be from 500 kg to 360 tonnes.The units use a conventional lining.The structure of the charge may reach 90% of scrap iron and 10% iron.Sometimes the proportion of raw materials may be different.Lime, is added to the batch, plays the role of flux.The main chemical processes in electric arc furnaces are not particularly different from the open hearth.
The share
currents of industrial frequency induction heating of the metal is carried out.Due to the large mass of the core of such an impact is quite enough.To melting of steel weighing up to 100 tons of sufficient current frequency of 50 Hz.I must say that some of the parameters for different types of raw materials can be the same.For example, corrosion, heat-resistant stainless steel and have a share of 7,9 g / cm3.This rate is directly related to the weight of the finished product at the outlet.That is what it is, the product is therefore heavier.A proportion of galvanized steel, too, about 7.9 g / cm3.There may be a slight difference depending on the type.But the proportion of sheet steel - 7.85 g / cm3.As seen, the rate is slightly lower mean and lighter material.We must assume that the proportion of iron and steel is different.In the alloy output figure is higher as a rule.This is largely due to the fact that during processing, despite the fact that some components are removed from the raw material to the mixture is added additional elements.They have an impact on the parameters of the output product.Different types of iron have their specific gravity (g / cm3):
- White - 7,5 ± 0,2;
- gray - 7,1 ± 0,2;
- malleable - 7,5 ± 0,2.
calculation
ratio between the volume of the alloy and its mass is characteristic only of a particular substance.In addition, it is a constant parameter.Using a special formula you can find the density of matter.It has a direct relation to the calculation of the proportion of the alloy.Here's how it looks.
The proportion of metal is designated as the formula γ.It is the ratio of P - homogeneous body weight - in terms of connections.And is calculated as follows: γ = P / V.
It only works when the metal has a completely dense state, non-porous.
Conclusion New technologies, which are used in heavy industry, in many ways different from that used in the initial stage of development of the industry.Thanks to modern scientific progress matallopromyshlennost produces a huge amount of variation alloys.The proportion of compounds affects the choice of raw material to be used in production.If you take three different metals: iron, brass and aluminum with the same amount - then everyone will have different masses.Therefore, the choice of a metal must be taken into account, among other options, its share.
