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There Are Many Types Of Steel Structures Jul 03, 2017

Steel structure materials and structural steel types of what are the specifications

The type of a steel

According to the use can be divided into: structural steel, tool steel and special steel;

According to the smelting method can be divided into: converter steel and furnace steel;

According to the deoxidation method can be divided into: boiling steel (F), semi-killed steel (b), sedative steel (Z) and special sedative steel (TZ), cast steel and special cast steel code can be omitted;

According to the molding method can be divided into: rolling steel (hot rolling, cold rolling), Steel Structure forged steel and cast steel;

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

1. Steel grades

There are many varieties of steel, Steel Structure steel structure used in the steel are mainly two categories.

⑴ carbon structural steel

According to the current national standard "carbon structural steel" (GB700), the grades of carbon structural steels are represented by the letter Q of the yield point, the value of the yield point (N / mm2), Steel Structure the quality grade symbol and the deoxygenation

Method symbols and other four parts in order.

Carbon structural steel is divided into Q195, Q215, Q235, Q255 and Q275 five, the greater the yield strength, its carbon content, strength and hardness, the lower the plasticity. Which Q235 is in use, Steel Structure processing and welding

Then the performance is better, is one of the commonly used steel steel structure.

Quality level is divided into A, B, C, D four, from A to D that the quality from low to high. Different grades of grade steel on the chemical composition and mechanical properties of different requirements. Steel Structure Class A no impact work specified, only for cold bending tests

When the requirements of the demand side, the carbon, manganese, silicon content can not be used as delivery conditions; B, C, D, respectively, to ensure that 20 ℃, 0 ℃, -20 ℃ Chibi V-notch impact Power is not less than 27J (vertical

), Are required to provide a cold bend test qualified guarantee, as well as carbon, manganese, silicon, sulfur and phosphorus content of the warranty. Steel Structure All steel suppliers should provide the quality of mechanical properties such as yield point, ultimate strength and elongation

Paul

Boiling steel, quartz steel, semi-killed steel and special sedative steel were written in Chinese characters Pinyin F, Z, b and TZ said. For Q235, A, B grade steel can be Z, b or F, C grade steel can only be Z, D grade steel can only be TZ

The Z and TZ can be omitted.

Q235-B represents a Class B semi-killed steel with a yield strength of 235 N / mm2; Q235-C represents a C-stage with a yield strength of 235 N / mm2;

Sedative steel.

(2) low-alloy high-strength structural steel

Low alloy steel refers to the steel in the process of adding one or several small amount of alloying elements, the total less than 5% of the steel. Steel Structure The low alloy steel has a high strength due to the presence of alloying elements. According to the current national standard

Quasi-"low-alloy high-strength structural steel" (GBT / l591) requirements, and its grades and carbon structural steel grades that the same, commonly used low-alloy steel Q345, Q390, Q420 and so on.

     When the low-alloy steel is delivered, the supplier shall provide mechanical strength such as yield strength, ultimate strength, elongation and cold bending test. It also provides chemical composition such as carbon, manganese, silicon, sulfur, phosphorus, vanadium, aluminum and iron

The warranty.

In addition to the four grades of carbon structural steel A, B, C, D, increase the E grade, which requires 40 ° C when the Charpy V-notch impact force is not less than 27J (vertical). Different quality

Grade of carbon, sulfur, phosphorus, aluminum content requirements are also different. Low-alloy steel deoxidation method for the killed steel or special sedative steel. Steel Structure Q345-B indicates a B-grade killed steel with a yield strength of 345 N / mm2; Q390-

D represents a special grade steel with a yield strength of 390 N / mm2.

Carbon structural steels and low alloy steels can be used to further improve their strength by appropriate heat treatment (such as quenching and tempering treatment). Such as 45 high quality carbon steel for making high strength bolts and 40 boron (40B)

, 20 manganese titanium boron (20MnTiB) is through the quenching and tempering treatment to improve the strength.

Note: The classification and requirements of the quality grade: carbon steel (A, B, C, D) four, low alloy steel (A, B, C, D, E) five. The guaranteed conditions for steel at all levels are:

A grade steel - tensile strength, yield point and elongation, Steel Structure cold bending test only when the demand side, no impact toughness requirements;

B grade steel - tensile strength, yield point and elongation, cold bending test qualified, room temperature (20 ℃) impact test, the impact of the impact of not less than 27 J;

C grade steel - tensile strength, yield point and elongation, cold bending test qualified, 0 ℃ impact test, the impact of the impact of not less than 27 J;

D grade steel - tensile strength, yield point and elongation, cold bending test qualified, -20 ℃ impact test, the impact of the impact of not less than 27 J;

E grade steel - tensile strength, yield point and elongation, cold bending test qualified, -40 ℃ impact test, the required impact of not less than 27J.

Second, the specifications of steel

The steel used in the steel structure is mainly hot-rolled steel plate, steel and cold-formed thin-walled steel.

1. Steel plate

The steel plate has a thin steel plate (thickness 0.35 ~ 4mm), thick steel plate (thickness 4.5 ~ 60mm), special thick plate (plate thickness> 60mm) and flat steel (thickness 4 ~ 60mm, width 12 ~ 200mm) and so on. Steel plate with "- wide ×

Thick × long "or" - wide × thick ", Steel Structure expressed in units of mm, such as -450 × 8 × 3100, -450 × 8.

2. Steel

Steel structure commonly used steel is angle steel, I-shaped steel, channel and H-beam, steel and so on. In addition to H-beam and steel pipe with hot rolling and welding molding, the remaining sections are hot-rolled molding.

(1) angle steel

Corner has two kinds of equilateral angle and unequal angle. Equilateral angle to "L limbs wide × thick", said, ranging from angle steel to "L long limbs wide × short limbs wide × thick", the unit is mm, such as L63 × 5,

L100 × 80 × 8.

(2) I-beam

I-beam has two kinds of ordinary I-beam and light-type I-beam. Ordinary I-beam with "I cross-section height of the centimeter" that the height of 20mm or more I-beam, the same height of three kinds of web thickness, were recorded as a, b

, C, a type of web thinnest, Ji edge of the narrowest, b class thicker wide, c class thickest and widest, such as I20a. The same height of the light I-beam flange than the ordinary I-beam edge of the wide and thin, thin web, light industry

The word steel can be expressed in Chinese phonetic symbols "Q", Steel Structure such as QI40 and so on.

(3) channel steel

Channel is also divided into ordinary channel and light channel two, "[or Q [cross-section height centimeters" said, such as [20 b, Q [22].

(4) H-beam

H-type steel hot rolling and welding two. Hot-rolled H-beam has four kinds of wide flange (H W), middle flange (HM), narrow flange (HN) and H-shaped steel column (HP). H-beam with "height × width × web thickness ×

Flange thickness ", in units of mm, such as HW250 × 250 × 9 × 14, HM294 × 200 × 8 × 12.

Welding H-beam is made of high-frequency welding of steel plate, also used "height × width × web thickness × flange thickness" said, such as H350 × 250 × 10 × 16.