classification of construction steel

classification of construction steel

Construction steel products are generally divided into rebar, round bar, wire rod, spiral steel and other categories.

1. Rebar
The general length of rebar is 9m and 12m. 9 meters’ Rebar is mainly used for road construction and 12 meters’ long Rebar is mainly used for bridge construction. The specification range of Rebar is generally 6-50mm, and deviation is allowed by the state. According to the strength, there are three types of rebar: HRB335, HRB400 and HRB500.

2. Round bar
As the name suggests, round bar is a solid strip steel with circular section, which is divided into hot rolling, forging and cold drawing. There are many materials of round steel, such as: 10 #, 20 #, 45 #, q215-235, 42CrMo, 40CrNiMo, GCr15, 3Cr2W8V, 20CrMnTi, 5CrMnMo, 304, 316, 20Cr, 40Cr, 20CrMo, 35CrMo, etc.
The specification of hot-rolled round bar is 5.5-250mm. The 5.5-25mm round bar belongs to small round bar steel, which is supplied in straight bars in bundles and is used for reinforcing bars, bolts and various mechanical parts. The round bar more than 25mm is mainly used for manufacturing mechanical parts or seamless steel tube blank.

3.Wire rod

There are three common types of wire rod: Q195, Q215 and Q235. However, there are only two kinds of wire rod for construction steel: Q215 and Q235. The commonly used diameters are 6.5mm, 8.0mm  and 10mm. At present, the largest wire rod in China can reach 30mm in diameter. The wire rod can also be used for wire drawing and wire rod as well as reinforcement for building reinforced concrete.

4.Spiral steel

As the name suggests, the spiral steel is the thread steel coiled together like wire rod, which is the same as the bundling method of ordinary wire rod, but it needs to be straightened when it is used. In general, 6.5-8.0-10-12-14 steel products are mostly used for construction.

There are many kinds of steel bars, which are usually classified according to the chemical composition, production process, rolling shape, supply form, diameter and the use of steel bars in the structure.

(1) According to rolling Profile
① Smooth steel bar: Grade I steel bar (Q235 steel bar) is rolled into smooth round section, and supplied in the form of circle, with diameter no more than 10mm and length of 6m ~ 12m.
② Ribbed steel bars: there are spiral, herringbone and crescent shapes. Generally, grade II and III steel bars are rolled into spiral and crescent shapes, while grade IV steel bars are rolled into spiral and crescent shapes.
③ Steel wire (including low carbon steel wire and carbon steel wire) and steel strand.
④ Cold rolled and twisted steel bar: cold rolled and cold twisted.

(2) By diameter
Steel wire (diameter 3-5mm)
Fine steel bar (diameter 6 ~ 10mm)
Coarse reinforcement (diameter greater than 22mm).

(3) Classification by use
Wire rod is generally made of ordinary carbon steel and high quality carbon steel. According to the steel distribution catalog and different uses, wire rod includes ordinary low carbon steel hot rolled wire rod, high quality carbon steel wire rod, carbon electrode wire rod, Quenched and Tempered Threaded wire rod, wire rod for steel wire rope, piano wire rod and stainless steel wire rod.
1. Ordinary low-carbon steel hot-rolled strip (gb701-65). Ordinary low-carbon steel hot-rolled strip is made of low-carbon ordinary carbon structural steel or carbon structural steel with lower yield point. It is the most widely used wire rod, also known as flexible wire. This is the general line
Main uses: the general line is mainly used for reinforced concrete structure in building, or cold drawn steel wire for binding.
2. Ordinary low carbon steel non twist controlled cooling and hot rolling wire rod (zbh4403-88), non twist controlled cooling and hot rolling wire rod are made by non twist high speed wire rod mill with controlled cooling after rolling, and the material is the same as common wire rod, but non twist controlled cooling and hot rolling wire rod have the advantages of high dimensional accuracy, good surface quality and high mechanical properties. This is the high line
Main application: non twist controlled cold and hot rolled wire rod, dimension accuracy is divided into a, B and C levels. A. Class B and C precision are suitable for wire drawing, construction, packaging and welding rod, and class B and C precision are suitable for processing into bolts, screws and nuts.

 

Sheryl

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