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The production process of steel structure grid:

1. Mechanical index of steel structure: The mechanical index of structural steel includes yield point, tensile strength, elongation and low temperature impact toughness. These indicators should meet the requirements of the "Code for Design of Steel Structures", but the low temperature impact toughness should only be checked when the structure may be operated in a low temperature environment. The determination of steel mechanics indexes must comply with the "Sampling Regulations for Steel Structure Mechanics and Process Performance Testing" (GB2975-82)

2. Chemical composition of steel structure engineering: related to the machinability, toughness and durability of the steel structure. Among them are mainly the content of carbon, the content of alloy elements and the content of impurity elements such as sulfur and sulfur should meet the requirements of the specification (GB222-84).

3. Process performance: Process performance mainly includes solderability and processing performance. The weldability is related to the carbon content or carbon equivalent (low alloy steel), and can be identified by the weldability test. The processing performance is determined by the cold bending test. Press (GB232-88) as the standard.

4. Geometric size deviation: The deviation of the outer dimension of the steel structure (steel plate, section steel, round steel, steel pipe) from the theoretical size * must be within the allowable range. The allowable deviation value can refer to national standards GB709-88, GB706-88, GB787-88, GB978-88, GB707-88, GB816-87, etc.

5. The shape of the steel structure is missing *: the surface of the steel structure must be free of air bubbles, knots *, cracks, cracks, folds, inclusions, and pressed scales. These gaps must be * divided, and the depression * of the area after * divided shall not be greater than the negative deviation of the thickness of the steel structure. In addition, when there are rust, pitting or scratches on the surface of the steel structure, the degree of * shall not be greater than 1/2 of the negative deviation of the thickness of the steel structure.

6. Mechanical cutting: use mechanical force (shearing, sawing, grinding) to cut, the corresponding machinery includes shearing machine, sawing machine, grinder, etc., which is more suitable for linear cutting of steel plates or profiles with thickness below 12-16mm .

7. Gas cutting: Use oxygen-acetylene, propane, liquefied petroleum gas and other flames to heat and melt the metal, and use compressed air to blow away the molten metal, so that the metal is cut off, suitable for curved cutting and multi-head cutting.

8. Plasma cutting: the use of plasma arc flow to achieve cutting, suitable for cutting high-melting materials such as stainless steel.

9. Hot forming processing: it refers to heating the steel structure to a certain temperature before processing. This method is suitable for forming, bending and correcting workpieces that can be made at room temperature. The termination temperature of hot working shall not be lower than 700 ℃. When the heating temperature is 200 ~ 300 ℃, the steel structure produces blue brittleness, hammering and bending are strictly prohibited. Steel structures with carbon content outside the range of low-carbon steels are generally not hot-workable.

10. Cold forming: it is carried out at room temperature. Because the external force exceeds the yield strength of the material, the required permanent deformation of the material occurs, or because the external force exceeds the maximum strength of the material, some parts of the material are separated from the material as required. Cold working has a tendency to make the material hard and brittle, so the heat treatment can be used to restore the steel structure to a normal state or plan to remove the hardened edge parts. Carbon steel shall not be cold worked when the ambient temperature is below -16 ° C. When it is lower than -12 ℃, low alloy steel shall not be processed.