The steel used for steel structure is mainly hot-rolled steel plate, section steel and cold-formed thin-walled section steel.
1. Steel plate
Steel plates include thin steel plates (thickness 4-60mm, width 12-200mm), etc. The steel plate is represented by "one width * thickness * length" or "one width * thickness", and the unit is mm, such as -450*8*3100, -450*8.
2. Section steel
The commonly used steel sections of steel structures are angle steel, I-shaped steel, channel steel, H-shaped steel, steel pipe, etc. Except that H-section steel and steel pipe are hot rolled and welded, other sections are hot rolled.
3. Angle steel
Angle steel can be divided into equal angle steel and unequal angle steel. Equilateral angle steel is represented by "l limb width * limb thickness", and unequal angle steel is represented by "l long limb width * short limb width * limb thickness", in mm, such as l63*5, l100*80.
4. I-beam
There are two kinds of I-beam: ordinary I-beam and light I-beam. Ordinary I-beam is represented by "centimeters of I-section height". For I-beam with a height of more than 20mm, there are three web thicknesses at the same height, which are recorded as a, B and C respectively. Class a web is the thinnest and narrowest, class B is thicker and wider, and class C is the thickest and widest, such as i20a.
5. Channel steel
Channel steel is also divided into ordinary channel steel and light channel steel, expressed by "[or q{section height cm", such as 20b, q]22, etc.
6. H-shaped steel
H-beam is divided into hot rolling and welding. Hot rolled H-section steel has four types: wide flange (HW), middle flange (HM), narrow flange (HN) and H-section steel column (HP). H-shaped steel is represented by "height * width * web thickness * flange thickness", and the unit is mm, such as hw250*250*9*14, hm294*200*8*12.
Welded H-shaped steel is composed of steel plates by high-frequency welding. It is also expressed by "height * width * web thickness * flange thickness", such as h350*250*10*16.
7. Steel pipe
There are two kinds of steel pipes: hot rolled seamless steel pipe and welded steel pipe. The outer diameter of seamless steel pipe is 32-630mm. The steel pipe is represented by "outer diameter * wall thickness", and the unit is mm, such as 273*5exing.
Steel plates with a thickness of less than 5mm, steel pipes with a wall thickness of less than 3mm, and angle steels with a section of less than l45*4 or l56*36*4 should not be used as stress-bearing members of ordinary steel structures.
8. Cold formed thin-walled section steel
Cold formed thin-walled steel is made of cold-rolled steel sheet. Its wall thickness is generally 1.5-12mm, but the wall thickness of the load-bearing structure should not be less than 2mm. Thin-walled steel can make full use of the strength of steel to save steel, which is widely used in light steel structures.
Commonly used cold-formed thin-walled steel sections are equilateral angle steel (a), crimped equilateral angle steel (b), channel steel (c), crimped channel steel (d), Z-shaped steel, crimped Z-shaped steel (C-shaped steel) (E), steel pipe [(FGH)], etc.
The expression method is: it is expressed in the order of letter B, section shape symbol and long side width * short side width * crimping width * wall thickness. The unit is mm. When the long and short sides are equal, only one side width is marked, and when there is no crimping, the crimping width is not marked, such as [120*40*2.5, bc160*60*20*3].
Profiled steel plate is another form of cold-formed thin-walled steel. It is a corrugated plate made of 0.4-2mm thick steel plate, galvanized steel plate or color coated steel plate by cold rolling.
