1. The application of cold formed steel in the construction industry in developed countries

Cold-formed steel in foreign construction industry uses a very wide range, is used as the roof frame, purlin, truss, rigid frame, wall shelf, keel, roof, wall, floor, doors, 

windows, even vessels, pipelines, cofferdam, steel sheet pile and breakwater. In recent years, the combination of cold formed steel, the shell, the shelf, the single and 

multi - story buildings have also been developed rapidly, from the airport to the large shopping centers, from the Office buildings to the stadium, from the center to the 

residential housing, cold formed steel products are widely used in building design materials. In developed countries, the construction industry is the largest user of cold

formed steel, cold formed steel accounted for 5% of the total, construction industry with cold formed steel accounted for about 70% of the total. From the structural 

mechanics and economic point of view, the combination of cold formed steel and H steel in the construction industry is the best combination, can achieve industrial plant 

and residential construction factory.

column are used in the H steel. In 1984, Sendai, Japan after the earthquake, through the research of the Sendai earthquake damaged steel structure residence found, between

the column and the beam weld split. The reason is that restriction of H type steel shape structure characteristics, H type steel and H-shaped steel butt welding, weld too little. 

Therefore, after 1984, Japan by modifying the construction law, the provisions of the steel structure of the vertical column of the steel structure of the square tube must be used

to increase the length of the weld, so as to improve the seismic performance of residential. With the popularization of the application of cold formed steel in building steel structure,

the specification of cold formed steel has also increased, the maximum size of the square tube has reached 550 mm * 550 mm, the maximum wall thickness is 22 mm. The total 

output of the cold formed steel structure used in the steel structure in 2002 has reached 2000000 t. The current market demand for the largest steel pipe specifications for 

(200 mm * 200 mm) ~ (400 mm* 400 mm), these specifications are covered by the cold bending square tube, rectangular tube total of more than 80%, other specifications of the 

market share of less than 10%.

In the United States, Zelkowa acuminata relevant survey data show that amount of cold-formed rectangular tube and hot rolled H-section steel in construction industry is about 1: 1,

in the 90s of the 20th century, building steel structure used the proportion of cold-formed steel even more than the amount of hot-rolled H-beam. Among them, the cold formed 

welded pipe (including square tube and the original pipe) about 25% of the steel structure of the construction steel, in addition, the United States each year also imports a certain 

number of structural steel pipe. The world iron and steel statistics monthly! 2003 the 7th period of statistics, 2003 may U.S. structure with steel imports for 28 728 T, 1 ~ 5 month

imported a total of 164 210 T, an increase of 10% compared to the same period in 2002. In the United States, the proportion of all kinds of cold formed steel in the steel structure

is also more than 20%.


2. The application of cold formed steel in building industry in China

In our country's industrial and civil construction, the steel reinforced concrete has been used for many years, the construction period is long and the pollution is large. In recent years, 

with the success of Maanshan Iron and steel, Laiwu Steel Hot Rolled H-section steel products market promotion, application of steel structure in the construction industry continues to

expand, steel structure building, model room, mark buildings have launched, design, construction standards and norms also began to enter gradually perfecting stage, the steel structure

industry in China in recent years much closer step. However, at present, the application of construction steel structure in China.

If hot rolled H steel and welded steel structure, the annual output of hot-rolled H steel has more than 1500000 T, and the output of light H type steel and various steel structures also

have hundreds of thousands of T, and the output of our country has about 7000000 t. Cold formed steel in our country construction steel structure in the application in the initial stage,

the cold formed square rectangular structure welded pipe instead of hot rolled H steel for steel structure of the column has just begun, other cold formed steel in the construction industry

application less.

China's Ministry of construction has been in industry, civil construction, construction steel structure of the test building, built in Tianjin for example, 2002, two building construction steel 

structure housing demonstration project, the project adopts the structural system of steel tube concrete column and steel beam frame - steel reinforced concrete core tube (SRC), 

engineering a total area of 8 000 m2, the main body (11) layer, a building columns with circular tube and another building column with square steel tube 350 mm to 350 mm, thickness

with the floor changes changes, of which 1 3 layer for 16 mm 4 ~ 6 layer is 14 mm, 7-12 layer 9 to 12 mm, 10 ~ 11 layer is 10 mm, tube perfusion C40 concrete. The beam welded 

I-beam, specifications for the 350 mm* 200 mm *10 mm*18 mm, the floor is of high strength spiral rib reinforced prestressed composite slab. Because of the domestic manufacturers 

have so large diameter square tube, square steel tube is used in the project of BOX column four plate welding.

Tianjin two construction of steel structure demonstration residential construction of cold formed steel (mainly structural pipe) in the steel structure of the application of two inspiration:

one is the large size of cold formed steel market space, the reasonable number of steel structure is 10~ 18 layer, so the structure of the cold bending square tube specifications have 

certain requirements. Second, square steel tube with circular steel tube have obvious advantages, its reason, same length and diameter, round tube, square tube bearing force and 

seismic performance is better, according to the test of three layers of two cross tube and round tube concrete column frame in a university in Tianjin, the side length of the square tube.

column 150 mm, round tube with a diameter of 150 m.

Know More About:  Cold roll forming machine