According to the different chemical compositions, steel bars and steel wires can be divided into:

According to the different chemical compositions, steel bars and steel wires can be divided into:

According to the different chemical compositions, the steel wire can be divided into alloy steel wire and carbon steel wire, and carbon steel wire can be divided into low carbon steel wire, medium carbon steel wire and high carbon steel wire.

Hot-rolled ribbed steel bars for reinforced concrete" GB1499 and "Thermo-optical round steel bars for reinforced concrete" GB1499 have been implemented since March 1, 2008: GB, there is no transition period. Replaces the original standard.

Replaces the original standard. 1-2008;%)c carbon si silicon mn manganese p phosphorus s sulfur hpb235 hpb300 0, there is no transition period. 3 0, and GB13013-1991 "hot-rolled round steel bars for reinforced concrete".

25 0。HRB335 1, the original standard is invalid. 045 0;The corresponding part of T701-1997 "Mild Steel Hot Rolled Disc Rod" has been implemented on September 1, 2008.

2-2007, the old regulations have not changed, and the chemical content of the brand is not greater than ( .045 0, the original standard is invalid. 55 0：

GB1499-1998 "Hot-rolled ribbed steel bars for reinforced concrete" Steel bars New standard steel bar grade yield strength (MPa) tensile strength (MPa) elongation ( ) HPB235 235 370 25 HPB300 300 420 HRB335 335 455 (490) 17 (16) HRB400 400 540 (570) 16 (14) HRB500 500 630 (630) 15 (12) The chemical composition of the steel bar is required to be new 1

In addition to the main chemical component iron (Fe), the steel bar also contains a small amount of carbon (C), silicon (Si), manganese (Mn), phosphorus (P), sulfur (S), oxygen (0), nitrogen (N), titanium (yang, alum ( ) and other elements. (1) Carbon is an important element that determines the performance of steel bars, and it has a great impact on the mechanical properties of steel. When the carbon content in the steel is below, with the increase of carbon content, the strength and hardness of the steel increase, and the plasticity and toughness decrease.

For steels with greater carbon content, their weldability will be significantly reduced. (2) Silicon is a beneficial element in steel, and it plays a role in deoxidation in steelmaking. It is the main alloying element of steel in China, and its role is mainly to improve the mechanical strength of steel.

3) Manganese is a beneficial element in steel, which can play a role in deoxidation and desulfurization in steelmaking, which can reduce the thermal brittleness caused by sulfur, improve the hot working properties of steel, and improve the strength and hardness of steel. (4) Phosphorus is one of the most harmful elements in steel. With the increase of phosphorus content, the strength and hardness of the steel are improved, and the plasticity and toughness are significantly reduced, especially the lower the temperature, the greater the impact on the plasticity and toughness, thereby significantly increasing the cold brittleness of the steel.

Phosphorus significantly reduces the weldability of steel, but improves the wear and corrosion resistance of steel. Construction steel generally requires a phosphorus content of less than 0. 045%。

5) Sulfur is a very harmful element, which can reduce various mechanical properties of steel. Sulfur reduces the weldability, impact toughness, fatigue resistance and corrosion resistance of steel. Construction steel generally requires that the sulfur content should be less than.

6) Oxygen is a harmful element in steel, which can reduce the mechanical properties of steel, especially toughness. Oxygen has the effect of promoting aging tendency. The low melting point caused by the oxide also makes the weldability of the steel worse.

It is usually required that the oxygen content in the steel is less than. (7) The effect of nitrogen on steel is similar to that of phosphorus and sulfur, which increases the strength of steel and significantly decreases plasticity, especially toughness, which will aggravate the aging sensitivity and cold brittleness of steel and reduce weldability. It is usually required that the nitrogen content in the steel is less than.

8) Titanium is a strong deoxidizer, which can significantly increase strength and improve toughness, but slightly reduce plasticity. Titanium reduces aging tendencies and improves weldability. (9) Vanadium is a weak deoxidizer, which can weaken the adverse effects of carbon and oxygen when added to steel, which can effectively improve the strength and reduce the sensitivity of efficiency, but has a tendency to increase hardening during welding.

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The examination is that the steel bar is classified according to the production and processing workers, and the steel bar is classified according to the production and processing technology: it can be divided into: hot-rolled steel bar, heat-treated steel bar, cold-drawn steel bar and cold-rolled steel bar.

In reinforced concrete, according to the function, the reinforcement can be divided into several types of reinforcement?

Dear, hello, I am happy to answer for you: in reinforced concrete, according to the role to distinguish, steel bars can be divided into 4 types of steel bars 1, stressed beam steel bar: in reinforced concrete structure, according to the structural calculation, the steel bar that bears tension or pressure is the main part of the configured steel bar.

2. Erection reinforcement: positioning reinforcement set up to meet the requirements of structure or construction. The function is to fix the main stressed steel bars (such as main steel bars, stirrups, etc.) in the correct position, and connect with the main steel bars to form a steel skeleton, so as to give full play to their respective force characteristics.

3. Distributed reinforcement: structural reinforcement set perpendicular to the stress direction of the plate or beam. Its function is to transfer the load acting on the plate or beam to the stressed steel bar more evenly, and at the same time, the position of the steel bar can be fixed by binding or spot welding in the construction, and is used to resist temperature stress and concrete shrinkage stress.

4. Structural reinforcement: the reinforcement that needs to be configured due to the structural requirements of the components and the construction and installation. Erection bars and distribution bars also belong to structural bars.

Chemical composition In addition to the main chemical component Fe iron, steel also contains a small amount of carbon (C), silicon (Si), manganese (Mn), phosphorus (P), sulfur (S), oxygen (0), nitrogen (N), titanium (To, vanadium (V) and other elements, although the content of these elements is very small, but it has a great impact on the performance of steel.

What are the categories according to the chemical composition of steel bars?

1. Carbon steel bar: Carbon steel bar is rolled from carbon steel. According to the provisions of the national standard "Technical Standard for Ordinary Carbon Structural Steel" (GB700-79), ordinary carbon structural steel is divided into the following three categories according to the guarantee conditions of the factory:

Class A steel - steel that guarantees mechanical properties; It is denoted by the symbol A.

Class B steel – steel with a guaranteed chemical composition; It is denoted by the symbol B.

Special steel - steel that guarantees both mechanical properties and chemical composition. It is denoted by the symbol C.

The larger the steel grade, the higher the carbon content, the higher the strength and hardness, but the plasticity, toughness, cold bending and weldability are reduced.

2. Ordinary low-alloy steel bars: Ordinary low-alloy steel bars are steel bars made by adding a small amount of elements (silicon, manganese, titanium, rare earths, etc.) to the composition of low-carbon and medium-carbon steel.

Its steel number and representation method: The steel grade of ordinary low-alloy steel is expressed according to the type of carbon content and gold element. The first number represents the average carbon content of 10,000 parts per thousand, the following chemical element names are the alloying elements added, and the number after the alloying elements indicates the content of alloying elements.

When the average content of alloying elements is 5 to 50 a ......, the number should be written as 2, 3, 4 ...... accordinglyIf the average content of alloying elements is less than 1 5, no number is attached to the alloying elements. For example, "20 mnsi" is read as 20 manganese silicon steel, which means that the carbon content is 20 parts per 10,000, and it is composed of two alloying elements, manganese and silicon, and the average content of alloying elements is less than 1 5%.

The main advantages of ordinary low-alloy steel bars are high strength, good comprehensive performance, and the amount of steel used is about 20 less than that of carbon steel.

Commonly used ordinary low-alloy steels include 20 manganese silicon, 25 manganese silicon, 40 silicon, manganese vanadium and other varieties.

Carbon and steel. Steel wire is one of the four major varieties of steel plate, tube, profile and wire, and it is a hot-rolled wire rod.

Reprocessed products made by cold drawing. According to the cross-sectional shape, there are mainly circles, squares, moments, triangles, ellipses, flattens, trapezoids, Z-shapes, etc.; Classified by size, there are extra-fine millimeters; Classified by intensity, there are low intensity 3135 megapascals; According to the use of classification: ordinary quality steel wire including welding rod, nail making, net making, packaging and printing industry steel wire, cold top forging steel wire for cold heading rivets, screws, etc., electrical steel including the production of overhead communication lines, steel core aluminum stranded wire and other special steel wire, textile industry steel wire including comb, heald 013, card clothing and needle steel wire, rope wire wire for the production of wire rope and spokes, spring steel wire including spring and spring washer.

Steel wire for piano and tires, cord and transportation tape, structural steel wire refers to steel wire for watch industry, ball, automatic machine easy cutting, stainless steel wire includes stainless steel wire and surgical implant wire for the above purposes, resistance alloy wire for heater elements and resistance elements, tool steel wire includes steel wire and shoe-making wire.

In engineering, it is usually classified according to chemical composition, which is divided into carbon steel, low-alloy steel, and alloy steel.

Indication of steel product grade: Chinese pinyin + chemical symbol + Arabic numerals.

The carbon structural steel grade contains information: the letter Q indicating the yield point, the yield point grade, the quality grade, and the degree of deoxidation. Determined according to GB T700-1988.

There are five types of yield point values: Q195, Q215, Q235, Q255, Q275; Expressed as a yield point of 235n mm2. Such as: Q235-A b C

Quality grade: refers to the amount of sulfur and phosphorus impurities. There are four grades: A, B, C, and D.

High-quality carbon steel (implementation standard GB T699-1999) grade: expressed in two digits, representing the percentage of carbon content. Such as: 20

Low-alloy high-strength alloy steel grade representation method: yield point grade + quality grade.

Yield point grades: Q295, Q345, Q390, Q420, Q460

Quality grades: e, d, c, b, a

There are several regulations on the representation of alloy structural steel grades:

Alloy structural steel and spring steel: a two-digit representation of the average carbon content of several parts per thousand;

Stainless acid-resistant steel, heat-resistant steel: the average carbon content is expressed in thousands; When the average C content is 0, it is represented by 0 (low carbon); c, it is represented by 00 (ultra-low carbon); When the content of C is 1%, the content of C is not labeled;

When the average alloy content is average, only the elements are marked in the grade, and the alloy content is not marked;

The average alloy content is 2, 3 ......

According to the chemical composition, steel can be divided into two categories: carbon steel and alloy steel.