became known as a compound of iron and carbon.Types of materials are determined not by the ratio of the main components, and on the basis of the impurities and additives, endowing the product different properties and characteristics.
types of steel, according to the pricing policy can be divided into subgroups, cheap, popular and costly.It all depends on the purpose of the material difficulties of its production.And there is clearly good or bad alloy as the material contains a set of features that meet certain conditions.Specifically, it can be seen if we consider, for example, 440 steel.
steel components
quality steel should be characterized at the same time wear resistance, strength, elasticity, ductility, toughness, corrosion ability and endurance sharpening.In practice, almost all of these properties are contrary to each other.One of the major alloying elements responsible for the hardness and stiffness, is carbon.For compounds with high content of it include those in which the concentration of the chemical element is greater than 0.5%.Wear resistance properties and a low tendency to corrosion gives steel chrome.If its level is greater than 13%, this stainless steel products.
Grain, strength, stiffness gives the alloy and manganese.It is used at the stage of forging and rolling.This so-called steel deoxidation.To
products of this material were not brittle and fragile and yet are resistant to heat, a molybdenum compound is added.In this case, the alloy is called air-quenched.
Helps reduce the risk of corrosion and gives the hardness of nickel.Property Fortress provides material silicon.Tungsten and vanadium alloy gives strength and durability.
Features steels 440
440 steel refers to stainless materials.It is used mainly for the manufacture of knives, building structures.The distinguishing feature of this alloy is resistant to corrosion and high strength.Also advantage of this series is the resistance to environmental factors, water, to food, weak acids and alkalis.
Steel grade 440 includes subspecies 440A, 440B, 440C, and 440A series - softer than others, and 440C - harder.However, minus 440C is a fragility and a relatively low resistance to rust with respect to the 440A and 440B.It turns out that with prolonged contact with moisture or corrosive media may appear corrosion.Although additional properties, rust preventive, gives this alloy because of the smooth polished surface.
not recommended to use 440 steel at a temperature higher than its heating during the holidays, as in this case, lost the mechanical properties of the alloy.
440 Chemical composition of steel
Steel 440, the characteristics of which are directly dependent on the chemical composition, according to the series, contains the elements given in the table below.
| chemical element | Brand 440A | Mark 440V | Brand 440C |
| Carbon | 0,6-0,75 | 0,75-0,95 | 0,95-1,2 |
| Chrome | 16-18 | 16-18 | 17-18 |
| Manganese | 1 | 1 | 1 |
| Vanadium | - | - | - |
| Molybdenum | 0,75 | - | 0,75 |
| Nickel | - | - | - |
| Silicon | 1 | 1 | 1 |
As can be seen from the table, the lowest carbon content of the Series 440A, the highest - 440C, that is,latest brand stronger than all, and the first is the most resistant to corrosion.While all the series of this brand is quite high-quality and well tolerated load.
physical properties and heat treatment of stainless steel 440
Steel 440 characteristics of physical indicators for the series A, B and C are as follows:
- material density - 7650 kg / cu.m;
- modulus of elasticity - 200 GPa;
- thermal conductivity - 242 W / m KB .;
- specific heat capacity - 460 J / kg.kb .;
- resistivity - 600.
hardness steel 440 varies between 56-58 units.
average coefficient of thermal expansion, which is measured in mm / m / ° C, in the series 440A - 10.1;440B - 10.3;440C - 11.7.
heat treatment of the material passes through the following stages:
- joke;
- quenching;
- vacation.
Annealing takes place at + 850-900 degrees Celsius, followed by a permanent decline to _600.Cooling occurs by air method.Then - a procedure fading annealing at 735-785 degrees and cooling in the furnace.
Tempering performed at + 1010-1065 degrees Celsius.Quenching - by means of warm air or oil.
Vacation passes at + 150-370 degrees, allowing the material to give the necessary hardness.Among the varieties of material such as steel 440, the characteristics of mechanical stress from the best brands of 440C.This alloy is the most costly and reliable.It defines the standard for quality products.
Applications
steel 440 Stainless steel 440 is most commonly used for the manufacture of knives.Hire this alloy for building products that are welded or other compounds.
Sheets finished products are produced with a thickness of 4 mm to 50 mm.440 steel does not require additional heating and heat treatment during her welding.Convenient and reliable alloy for the production of bearings, pieces of pipe fittings.
From brand 440A produces more clumsy knives, including underwater, hunting.The blades of a series 440C have excellent cutting properties and good endurance sharpening, so this steel is used for the production of elite cutting tools.
need to know when buying a knife labeled "440", which is used less expensive alloy - 440A.In the case of more expensive compounds 440B and 440C manufacturers always pay attention to it.
alternative brand
There are a number of alternative brands, which can replace the alloy.For example, a series of 440A / B possesses additional features that improve the corrosion resistance.Steel 440F has higher workability for the same strength.Inferior to their own characteristics in hardness grade 420. The 416 series has a high workability, but a lower reliability.If
make knives from mark 440A and its analogues, these products are suitable for everyday use.Although, it is worth to take into account the quality of quenching.Well proven in the course of company Cor.The company "Randall" mainly produces steel blades 440B.
