There are three main kinds of steels when selecting suitable steels for CNC machining: Stainless Steel, carbon steel and alloy steel. Here , the concpts, kinds, alloying elements, grades of alloy steels and the differences between alloy steels and carbon steels are introduced in detail.
What's the meaning of alloy steel?
It means a kind of alloy elements is commonly from 1% to 50% by weight. Strength, hardness, toughness, corrosion resistance, and more characteristics could be enhanced. Alloy steels are generally classified into low alloy steels and high alloy steels.
Alloy steel becomes the main force in industry because of its cost, lots of applications and excellent mechanical features. Alloy steels are widely adopted in applications where strength, toughness and corrosion resistance are significant, like construction and construction, also in the production of kitchenware, housewares and jewelry.
kinds of Alloy steels
high alloy steels: defined by high proportions of alloying elements. Alloy steel is divided into low alloy steel and high alloy steel. The content of alloying elements in high alloy steel is more than 10% .
LOW ALLOY STEEL: low in alloying elements, commonly from 1% to 5% . If the alloy element content of the steel is less than 5% , it is named low alloy steel. Low Alloy steels are characterized by the addition of chromium, Molybdenum and, sometimes, nickel. At the same carbon content, the strengthening property of low alloy steel is improved compared with carbon steel, and its microstructure is more stable at high temperature.
Common Alloy Steel is 4140 Alloy Steel (CR-MO) , tight strength, perfect wear resistance, good toughness and ductility, high temperature stress and creep resistance.
What's the role of the main alloying elements in steel?
The amount of alloying elements affects its function as well.
MANGANESE: improves surface hardness and resistance to strain, hammering and impact, combined with sulfur and phosphorus to decrease Brittleness and also helps eliminate lots of oxygen from molten steel.
Nickel: Increases Strength, toughness and corrosion resistance.
Chromium: increased hardness, increased toughness and wear resistance.
COBALT: to improve the thermal hardness of cutting tools and other applications. -MOLYBDENUM: Increases Strength and resistance to shock and heat.
Tungsten: increase hardness, improve grain structure and heat resistance. A stable carbide; inhibited grain growth. Improve the toughness of Steel
Vanadium: Increase Strength, toughness, impact and corrosion resistance.
SILICON: Increases Strength and improves magnetic properties.
Boron: A strong hardener.
Alloy steel versus Carbon Steel
1. Elements. Alloy steels contain a large amount of other elements including iron and carbon, whereas carbon steels are high in carbon and low in other elements. In the carbon alloy, the content of carbon is as high as 2.1% , and the additional elements have no minimum content and are generally considered as impurities.
2. Strength. The Carbon steel is stronger than alloy steel.
3. Corrosion resistance. Alloy steel has high corrosion resistance.
4. Point of melting. Alloy steels have a higher point of melting commonly, however carbon steels have a lower point of melting .
5. Solderability. Alloy steel is easily weldable.
6. Extensibility. Alloy Steel has higher ductility.
7. Price. The Carbon steel is comparatively cheap than alloy steel.