The round steel is refers to the section of solid rectangular steel round. The specification is expressed by the diameter of the MM number, such as "50" means that the round steel 50 mm in diameter.

Steel material: Q195, Q235, 10#, 20#, 35#, 45#, Q215, Q235, 304, 316, 20Cr, 40Cr, 20CrMo, 35CrMo, 42CrMo, 40CrNiMo, GCr15, 65Mn, 50Mn, 50Cr, 3Cr2W8V, 20CrMnTi, 5CrMnMo etc..

The difference between steel and other steel: 1 appearance is not the same, round bar shape light round, no pattern without ribs, other reinforced surface appearance is engraved or ribbed, cohesive force which causes the small round steel and concrete, and the bonding force of other concrete reinforced with high. 2 ingredients are not the same, round (a steel) belongs to the common low carbon steel, alloy steel reinforced many other. 3 strength is not the same, round steel of low intensity, and other steel with high strength, that is, the diameter of round steel of the same size as compared with other steel, round steel can bear the pulling force than other steel is small, but the plastic round than the other reinforcing steel, round steel with that in the break before the larger deformation, and the deformation of reinforced in it the break before the much smaller.

1 according to the classification of chemical composition

Carbon steel by chemical composition (i.e. with carbon content) can be divided into low carbon steel, medium carbon steel and high carbon steel.

(1) low carbon steel

Also known as mild steel, carbon content from 0.10% to 0.30% low carbon steel is easy to accept all kinds of processing such as forging, welding and cutting, commonly used in the manufacturing chain, rivets, bolts, shaft etc..

(2) carbon steel

Carbon steel carbon content of 0.25% ~ 0.60%. Have killed steel, semi killed steel rimmed steel products, etc.. In addition to the carbon can also contain a small amount of Mn (0.70% ~ 1.20%). According to the quality of the products is divided into ordinary carbon structural steel and high quality carbon structure steel. Heat processing and good cutting performance, poor welding performance. The strength and hardness than low carbon steel high, while plasticity and toughness lower than that of low carbon steel. Without heat treatment, the direct use of hot rolled and cold drawn materials after heat treatment, can also be used. Quenching and tempering carbon steel has better comprehensive mechanical properties. The highest hardness can reach about HRC55 (H. The highest hardness can reach about HRC55 (HB538), sigma B is 600 ~ 1100MPa. So all kinds of uses in moderate intensity, medium carbon steels are the most widely applied, except as a building material, but also a large number of used for producing all kinds of machinery parts.

(3) high carbon steel

Often called tool steel, carbon content from 0.60% to 1.70%, can be hardened and tempered. Hammers, crowbars etc. by the carbon content of 0.75% steel; cutting tools such as drills, silk attack, reamer manufacturing by the carbon content of 0.90% to 1% steel.

2 according to the quality classification of steel

According to the steel quality can be divided into ordinary carbon steel and high quality carbon steel.

(1) ordinary carbon structural steel is also known as ordinary carbon steel, the carbon content, the performance range and phosphorus, sulfur and other residual element content limits wide. In Chinese and some countries according to the delivery guarantee conditions are divided into three classes: class a steel (a type of steel) is to ensure that the mechanical properties of the steel. Class B steel (B steel) is to ensure that the chemical composition of steel. Special steel (C steel) is not only ensure mechanical performance and ensure the chemical composition of steel, structural parts used in manufacturing is important. China present production and use most of the carbon content in about 0.20% of A3 steel (a steel No. 3), mainly used in engineering structure.

Some carbon structural steel also add a trace of aluminum or Nb (or other carbide forming elements) forming a nitride or carbide particles, to restrain grain growth, so that the steel reinforcement, steel saving. In China and certain countries, to meet the special requirements of professional steel, chemical composition and properties of the ordinary carbon structural steel is adjusted, and the development of a series of ordinary carbon structural steel for professional use steel (such as bridges, buildings, steel, pressure vessel steel etc.).

(2) compared with the high quality carbon structural steel and ordinary carbon structural steel, the content of sulfur, phosphorus and other non metallic inclusions in lower. According to the carbon content and the use of different, this kind of steel is roughly divided into three types: 1. Less than 0.25%C for low carbon steel, especially the carbon containing less than 0.10% 08F, 08Al, has a very good deep drawing and welding properties and is widely used as deep drawing parts such as the car, can...... Etc.. 20G is the main material for manufacturing the ordinary boiler. In addition, the low carbon steel is widely used as a carburizing steel, used in the mechanical manufacturing industry. In the 0.25 ~ 0.60%C in carbon steel, used in quenched and tempered state, making machinery manufacturing industry parts. The greater than 0.6%C for high carbon steel, used for the manufacture of springs, gears, rollers etc.. According to the content of manganese is different, can be divided into ordinary manganese content (0.25 ~ 0.8%) and high manganese content (0.7 ~ 1% and 0.9 ~ 1.2%) two steel group. Manganese can improve the hardenability, strengthened Ferritic, improve the steel yield strength, tensile strength and wear resistance. Usually in the manganese steel with high grade after additional labeled "Mn", such as 15Mn, 20Mn to be distinguished from the normal amount of carbon steel containing manganese.

3 according to the classification of use

According to use can be divided into carbon structural steel, carbon tool steel.

Carbon tool steel carbon content in 0.65 ~ 1.35% between, after heat treatment can be obtained with high hardness and high wear resistance, mainly used in the manufacture of tools, cutting tools, tooling and gage (see tool steel).

Carbon structural steel to steel yield strength is divided into 5 grades:

Q195、Q215、Q235、Q255、Q275

Q195, Q215, Q235, Q255, Q275

Because of the quality of each grade is divided into A, B, C, D level, with a maximum of four, and some only a; another method of deoxidation steel smelting difference.

Method of deoxidation symbols:

F -- rimming steel

B semi killed steel

Z - killed steel

TZ -- special steel