Types and technologies of cold-formed steels (square pipes)

There are many kinds of cold-formed steels, which are divided into three types, namely, open type, semi closed type and closed type according to the sectional shape. The main products are including cold-formed channel steel, angle steel, Z steel, cold-formed corrugated steel plate, square tube, rectangular pipe, electric welding special-shaped steel tube, rolling door and so on. The cold formed steel usually is less than 6mm in thickness and less than 500mm in width.

In China, the common specifications are including more than 400 types, such as equal side angle steel (25~75 mm in length), inner roll angle steel (40~75 mm length of limb length), channel steel (25~250 mm high), inner coiling channel steel (60~250 mm high) and reel Z shaped steel (100~180 mm high), etc. The products are widely used in mining, construction, agricultural machinery, transportation, bridges, petrochemical, light industry, electronics and other industries.

The cold rolled section steel of Puri company steel is the main material for making light steel structure which is made of steel or steel strip by cold bending. Its wall thickness can not only be made much thinner, but also greatly simplifies the production process and improves production efficiency. It is possible to produce all kinds of cold bending steel sections with uniform wall thickness, complex shape and different materials, which are difficult to be produced by general hot rolling method. In addition to be used to various building structures, this cold formed steel is also widely used in vehicle manufacturing as well as agricultural machinery manufacturing  There are many kinds of cold-formed steels, which are divided into three types, namely, open type, semi closed type and closed type according to the sectional shape. According to the shapes, they can also be divided into cold-formed channel steel, angle steel, Z steel, cold-formed corrugated steel plate, square tube, rectangular pipe, electric welding special-shaped steel tube, rolling door and so on.

According to GB6725-92 regulations, the cold-formed steel is made of common carbon structural steel, high quality carbon structural steel, low alloy structural steel plate or steel strip. The cold-formed steel, which belongs to economic section steel and is also a kind of high efficiency and energy saving material. It is a new type of steel with strong vitality. It is widely used in various fields of national economy. The application can be divided into 10 categories, including highway guardrail, steel structure, automobile, container, steel mould board and scaffolding, railway vehicle, ship and ship. Bridge, steel sheet pile, transmission tower, and so on.

In the production of cold formed hollow rectangular steels, there are two different forming technologies. One is to make a circle firstly and then change a square or rectangle; another is to directly form a square or rectangle. At present, in the field of square rectangular steel tube forming, the technology of direct and square forming is really advanced internationally. The technology of directly forming square or rectangle is more advanced than that of first round, square or rectangle. The process of forming the steel strip or rolling plate is greatly damaged by the process of turning the square or the rectangle, and the process of direct square and moment forming will do not cause damage to the material in the forming process. It can keep the mechanical and physical properties of the raw material well, and ensure the good quality of the product. It is understood that a large steel tube plant in Tai'an, Shandong, adopted technology about forming into square and rectangular directly. The result was very nice.

In recent years, the demand for cold-formed steels market in China has been increasing, and its application scope is expanding. At present, it is urgent to develop cold bending steel of stainless steel, galvanized sheet, high strength, ultra-high strength low alloy material, and super - thick, super thin section cold bending steel products.