steel casting

Carbon steel is usually used water-cooled quenching, but the small size of the medium carbon steel, especially for the 8-12mm in diameter, 45 # steel quenching prone to crack, this is a more complex issue. The measures being taken when the specimen was quenched in water and quickly stir, or the use of oil and cold cracks can be avoided.

Carbon steel can be classified according to carbon content for low-carbon steel, medium carbon steel and high carbon steel. High-carbon steel are tool steel, see "tool steel" section. Low-carbon steel, such as 20, were more commonly used to produce carburizing steel parts. Carburization heat treatment process is carried out before treatment, followed by quenching and tempering. After such a treatment has a high hardness parts surface while the Department has a good heart plasticity. The medium-carbon steel, such as the use of 45 steel under different conditions, heat treatment in different ways. Generally used in thermal processing to be done for quenching and tempering treatment, that is, high-temperature tempering after quenching. Other conditions can be used in normalizing treatment.

Carbon steel is the carbon content of less than 2%, and a small amount of silicon, manganese and phosphorus, sulfur and other impurities in the iron-carbon alloy. Industrial application of carbon steel carbon content generally less than 1.4%. This is because the carbon content of more than this amount, the steel show a great deal of hard and brittle nature, and processing difficulties, loss of production and use value. Carbon steel can be classified according to their different masses ordinary carbon structural steel and high-quality carbon structural steel two categories. High-quality carbon structural steel provides sulfur and phosphorus content than ordinary carbon steel to allow low, so mechanical properties better than ordinary carbon steel.
(1) manufacturing methods. Carbon steel smelting usually BOF, open hearth furnace carried out. BOF General Smelting ordinary carbon steel, while the open-hearth can be a variety of high quality steel smelting. In recent years, oxygen BOF steelmaking technology has developed rapidly, there is a tendency to replace the open-hearth steel. The refining of molten steel into the ingot mold, get all kinds of steel ingot. After forging, or rolling ingot after processed into various shapes of steel and forgings. Ingot processed through the pressure, can improve the steel's internal organization and distribution of inclusions, so the same composition of the steel ingot in superior performance than some.
(2) purposes. Strength of carbon steel is mainly used to manufacture machine parts and a variety of less demanding metal structures. Widely used in machinery manufacturing in all its aspects. Such as agricultural machinery, machine tools, and ships. It is a most widely used, uses the largest steel.

According to carbon content is divided into low-carbon steel (carbon content of 0.04% ~ 0.25%), medium carbon steel (carbon content of 0.25% ~ 0.6%), high-carbon steel (carbon content 0.6% ~ 1.35%).
By mass is divided into ordinary carbon steel, its harmful impurities phosphorus and sulfur content of less than 0.05%, including the A steel (A type of steel, to ensure the mechanical properties), B steel (B type steel to ensure the chemical composition) and the Special class steel (C type steel, to ensure the mechanical properties and chemical composition) - such as: Q235A, Q235B, A235C, Q235D, SS400, etc.; high-quality carbon steel, harmful impurities phosphorus and sulfur content of less than 0.04%; high-quality carbon Su Gang, harmful impurities phosphorus and sulfur content of less than 0.03% - such as: 45, S50C, S45c, P20 and so on.
By end-use is divided into carbon structural steel and carbon tool steel, the former is mainly used for manufacture of a variety of structural parts and machine parts, are generally within the low carbon and medium carbon steel; the latter for the manufacture of cutting tools, measuring tools, mold, etc. generally within the high-carbon steel.
Carbon structural steel in accordance with the yield strength of steel is divided into five grades:
Q195, Q215, Q235, Q255, Q275
As the quality of each grade were divided into A, B, C, D grade, the largest four, some only one; Another method of deoxidation of steel smelting difference.
Deoxy method Symbols:
F - boiling steel
b - Semi-killed steel
Z - killed steel
TZ - special killed steel

Carbon Steel
Carbon content of less than 1.35%, in addition to iron, carbon and limited within the silicon, manganese, phosphorus, sulfur and other impurities, the steel does not contain other alloying elements. The performance of carbon steel depends on carbon content. Carbon content increased, the strength of steel, the hardness increased, plasticity, toughness and weldability decrease. Compared with the other steel type, carbon steel using the first, low cost, performance range, the largest amount. For nominal pressure PN

According to carbon content is divided into low-carbon steel (carbon content of 0.04% ~ 0.25%), medium carbon steel (carbon cont