Threaded steel bars are ribbed steel bars, also known as ribbed bars, usually with two longitudinal ribs and transverse ribs that are evenly distributed along the length. The lateral ribs are spiral, herringbone and crescent shaped. It is widely used in the construction of civil engineering projects such as houses, bridges and roads. Mainly produced in Japan and Western Europe, China's North and Northeast China is also part of the production, China will have a certain volume of imports each year. However, many people do not know what are the specifications of the rebar . Let's take a look.
Rebar classification
There are two commonly used classification methods for the rebars: one is the geometric shape classification and the classification is based on the cross-sectional shape of the transverse ribs and the spacing of the ribs. For example, in British Standard (BS4449), the rebar is divided into type I, Type II. This type of classification mainly reflects the gripping properties of the rebar. The second is performance classification (level), for example, China's current implementation standard, in which the rebar is (G B1499.2-2007) and the wire is 1499.1-2008), and the rebar is divided into strength grades (yield point/tensile strength). In the three levels, Japanese Industrial Standards (JI SG3112) classify rebars into five categories according to overall performance; British Standards (BS4461) also specify several levels of rebar performance tests. In addition, it is also possible to classify the rebar according to its purpose. For example, it can be divided into ordinary rebar for reinforced concrete and heat-treated rebar for prestressed reinforced concrete.
Calculation of theoretical weight of threaded reinforcement
The nominal diameter (mm) squared of the rebar is multiplied by 0.00617 times the length L, and 0.617 is the weight of the round 10 rebar.
The weight of the rebar is proportional to the square of the diameter (radius), C/m = 0.617*D*D/100.
Weight per kilogram (Kg) = Diameter of rebar (mm) × Diameter of rebar (mm) × 0.00617.
Note: After the Φ12 (including 12) and Φ28 (including 28) steel bars, take the three digits after the decimal point, and Φ14 to Φ25 take the double digits after the decimal point.
Rebar specifications
The rebar specifications are usually required to be listed in the import and export trade contract. In general, the specifications of the rebar should include standard grades, nominal diameters of the rebars, nominal weights, ie, masses, specified lengths, and tolerance values ​​for the above-mentioned indicators. The recommended nominal diameters of the rebar standard are 6, 8, 10, 12, 16, 20, 25, 32, 40, and 50mm. The length of the supply of the rebar is divided into length and size, and the length of the threaded steel rebar for export in China is 6~12m. The range of the rebar rebar in Japan is 3.5~10m. The rebar made in China is sold. There is no requirement in the contract. Its length is usually 9m and 12m.
Screw reinforcement application
Rebar is widely used in the construction of civil works such as houses, bridges and roads. Large public facilities such as highways, railways, bridges, culverts, tunnels, flood control, dams, etc., as well as foundations for building construction, beams, columns, walls, slabs, and reinforced steel bars are indispensable structural materials. With the deepening of the degree of urbanization in China, the vigorous development of infrastructure construction and real estate has a strong demand for reinforced steel bars.
Twisted steel bar theoretical weight table
The diameter of the rebar (in mm) multiplied by 0.00617 times the length L; 0.617 is the weight of the round 10 rebars per meter. The weight of the rebar is proportional to the square of the diameter (radius)
C/m=0.617*D*D/100
Weight per kilogram (Kg) = Diameter of rebar (mm) × Diameter of rebar (mm) × 0.00617
Note: After the Φ12 (including 12) and Φ28 (including 28) steel bars, take three digits after the decimal point. Φ14 to Φ25 bars take the two decimal places after the decimal point.
Rebar prices
The main factors affecting the price of rebar are production cost, supply and demand, and speculation. These factors are also constrained by many other factors. Speculative factors sometimes lead to irrational rises or falls in the prices of rebar. It is understood that since March this year, the price of rebar has fallen in a weak downward trend, and related parties have analyzed that this status will continue for a short period of time.
Here we have collected the price trend of the rebar in Beijing. The price of the three-stage thread with the specification of 12-14mm is 3,090 yuan per ton, the price of the 18-25mm three-stage rebar is 3060 yuan per ton, and the specification is 28-32mm per ton. It is 3090 yuan. From the current point of view, the price of tertiary rebar is still lower than RMB 10 per ton. The price of the three-tiered rebar with 16mm specification is basically stable, while the four-level rebar is still operating steadily.
Note: This price is for reference only! Due to geographical differences, of course, the price will be different. For more details on the prices, please refer to the local distributors!
Thread reinforcement standard
1. Threaded Reinforced Bars Standard Overview Threaded bars are also known as deformed bars or shaped bars. The difference between this and the optical steel bar is that the surface has longitudinal ribs and transverse ribs, usually with two longitudinal ribs and transverse ribs evenly distributed along the length. Threaded steel bar is a small steel bar, mainly used for the skeleton of reinforced concrete building elements. In use requires a certain degree of mechanical strength, bending deformation and process welding performance. The raw material billets for the production of the rebar are carbon structural steel or low-alloy structural steel subjected to sedation smelting, and the finished steel products are delivered in the hot-roll forming, normalizing or hot rolling state.
2. Standard types of threaded steel bars There are two commonly used classification methods for threaded steel bars: First, they are classified according to geometric shape, and are classified or typed according to the cross-sectional shape of the transverse ribs and the spacing of the ribs. For example, in the British Standard, rebar is divided into Type I and Type II. This type of classification mainly reflects the gripping properties of the rebar. Second, the performance classification (level), such as China's standard, according to the strength level (yield point / tensile strength) will be divided into three grades of threaded steel; Japanese industry standards, according to the overall performance of the threaded steel is divided into five types British standards also specify several levels of performance testing for threaded bars. In addition, it is also possible to classify the rebar according to its purpose. For example, it can be divided into ordinary rebar for reinforced concrete and heat-treated rebar for prestressed reinforced concrete.
3, the standard specifications of commonly used threaded steel bars GB700-88 (carbon structural steel); GB/T2101-89 (the general provisions of the steel acceptance, packaging, marking and quality certificate); GB1499-91 (reinforced concrete); JISG3112-87 (98) (bar steel for reinforced concrete); JIS G3191-66 (94) (shape, size, weight and allowable difference of hot-rolled bar and coil bar steel); BS4449-97 (hot rolled steel bar for concrete structures).
4. Relevant considerations for threaded rebar standards The quality of the finished product of the threaded steel bars varies with the technological conditions of the metallurgical smelting furnace and the hot-rolled batch. The furnace number and batch number are the basis of the sampling inspection. Therefore, the import and export goods department and the warehousing department should pay attention to the marks on the reserved goods, and the export companies and the foreign trade departments must also distinguish the batches according to the standard requirements.
National standard screw steel specification sheet
Thread rebar meter speedometer
Specification Theory Quality Specification Theory Quality Specification Theory Quality Specification Theoretical Quality
Mmkg/mmmkg/mmmkg/mmmkg/m
5.50.184212.72409.869555.6
60.222222.984210.910061.7
6.50.260233.264512.510568
70.302243.554814.211074.6
80.395253.855015.411581.5
90.499264.175317.312088.8
100.617274.495518.612596.3
110.746284.835619.3130104
120.888295.186022.2140121
131.04305.556324.5150139
141.21315.926526.0160158
151.39326.316828.5170178
161.58336.717030.2180200
171.78347.137534.7190223
182.00357.558039.5200247
192.23367.998544.5220298
202.47388.909049.9250385
Rebar
The specifications of the hot-rolled round steel are 5.5-250 mm. Among them: 5.5-25mm small round steel is mostly supplied in bundles of straight strips, often used as reinforcement, bolts and various mechanical parts; round steel larger than 25mm is mainly used for manufacturing mechanical parts or as seamless steel tube blanks. Steel theoretical weight calculation method (unit: kg) Round bar: Weight per meter = 0.00617 * diameter * diameter (same as rebar and round bar)
Standards: (GB13013-91, GB699-1988, GB700-1988, GB3077-1988, GB702-1986, QJ/HG02.17-1991)
Specifications: 10-42mm (10,12,14,16,18,20,22,25,28,30,32,34,35,36,38,40,42mm)
Steel types: Q215, Q235, 45#, 50#, HG3, 20CrMnTi, 20Cr, 20CrMo, 35CrMo, 42CrMo, 60Si2Mn, 40Cr
Editor's summary: With the deepening of the degree of urbanization in China, the vigorous development of infrastructure construction, real estate and other construction industry, the demand for threaded reinforcement is also increasingly strong, rebar is an indispensable structural material in the construction of modern civil engineering.
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