440 steel - stainless steel. Steel 440: characteristics

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

Steel is a compound of iron and carbon. The types of this material are determined not due to the ratio of the main components, but based on impurities and additives that endow the product with different properties and characteristics.

Types of steel, according to the pricing policy, can be divided into subgroups: cheap, popular and expensive. It all depends on the purpose of the material, the difficulties of its production. Moreover, there is no uniquely bad or good alloy, since this material contains a whole range of characteristics that meet certain conditions. Specifically, this can be seen if we consider, for example, 440 steel.

Steel components

Quality steel should be characterized simultaneously by wear resistance, strength, elasticity, ductility, rigidity, anti-corrosion ability and sharpening endurance. In practice, almost all of these properties contradict each other. One of the main elements of the alloy responsible for hardness and rigidity is carbon. Compounds with a high content of it include those in which the concentration of thischemical element is more than 0.5%. Chromium gives steel the property of wear resistance and low tendency to corrosion. If its level is more than 13%, then it is a stainless product.

Grain, strength, rigidity gives the alloy manganese. It is used at the stage of forging and rolling. This is the so-called deoxidized steel.

To make products from this material not brittle and brittle and at the same time resistant to heat, molybdenum is added to the compound. In this case, the alloy is called air-hardening.

Helps reduce the risk of corrosion and hardens nickel. The property of the fortress provides silicon to the material. Tungsten and vanadium give the alloy strength and wear resistance.

Features of steel grade 440

440 steel refers to stainless materials. It is used mainly for the manufacture of knives, building structures. A distinctive feature of this alloy is corrosion resistance and high strength. Also, the advantage of this series is resistance to environmental factors, water, food, weak acids and alkalis.

Steel grade 440 includes subspecies 440A, 440B, 440C, and the 440A series is softer than others, and 440C is harder. However, the downside of 440C is brittleness and relatively low rust resistance compared to 440A and 440B. It turns out that with prolonged contact with moisture or aggressive environments, corrosion may occur. Although the additional rust prevention propertiesgiven to this alloy due to the smooth polished surface.

It is not recommended to use 440 steel at a temperature higher than its heating during tempering, as in this case the mechanical properties of the alloy will be lost.

Chemical composition of 440 steel

Steel 440, the characteristics of which are directly dependent on the chemical composition, according to the series, contains the elements shown in the table below.

Chemical composition of 440 series

Chemical element	Brand 440A	Brand 440V	Brand 440С
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 in the 440A series, the highest - 440C, that is, the last grade is the most durable, and the first is the most resistant to corrosion. Although all series of this brand are quite high quality and tolerate loads well.

Physical properties and heat treatment of 440 stainless steel

Steel 440 physical characteristics for series A, B and C has the following:

• material density - 7650kg/cu. m;
• modulus of elasticity - 200 GPa;
• thermal conductivity - 242 W/m kb.;
• specific heat capacity - 460 J/kg.kb.;
• electric resistivity - 600.

The hardness of 440 steel varies between 56-58 units.

The average coefficient of thermal expansion, which is measured in mm / m / degrees Celsius, for the 440A series is 10.1; 440V - 10, 3; 440С - 11, 7.

The heat treatment of this material goes through the following stages:

• annealing;
• hardening;
• vacation.

Annealing takes place at a temperature of +850-900 degrees Celsius, followed by a constant decrease to _600. Cooling takes place by air. Then - the procedure of damped annealing at 735-785 degrees and cooling in the furnace.

Hardening is carried out at +1010-1065 degrees Celsius. Quenching - with warm oil or air.

Holiday takes place at a temperature of +150-370 degrees, due to which the material is given the necessary hardness. Among the varieties of a material such as steel 440, the mechanical impact characteristics are the best for grade 440C. This alloy is the most expensive and reliable. It defines the quality standard for products.

440 steel applications

440 stainless steel is mostly used for making knives. The rental of this alloy is intended for building products that have welded or other connections.

Sheets finishedproducts are produced with a thickness of 4 to 50 mm. 440 steel does not require additional heating and heat treatment when welding with it. Convenient and reliable alloy for the production of bearings, parts of pipeline fittings.

From brand 440A they produce large clumsy knives, including for underwater work, hunting. Blades from the 440C series have excellent cutting properties and good sharpening endurance, so this steel is used for the production of elite cutting tools.

You need to know when buying a knife marked "440" that a less expensive alloy is used here - 440A. In the case of using more expensive 440V and 440C connections, manufacturers always pay attention to this.

Alternative brands

There are a number of alternative grades that can replace this alloy. For example, the 440A/B series has additional properties that improve corrosion resistance. 440F steel has better machinability for the same strength. The 420 grade is inferior in its characteristics in hardness. The 416 series has increased machinability, but lower reliability.

If knives are made from brand 440A and its analogues, then such products are suitable for everyday use. Although, it is worth considering the quality of hardening. Cog has proven itself well in this process. Rendell mainly manufactures 440V steel knives.