Hot Rolled Steel Plates and Steel Strip (GB 709-88)
Hot rolled steel plates and steel strips are two types of rolled steel products manufactured in a steel mill. They are widely used for structural components in construction, automotive and other industries. This article will introduce the different aspects of the product and the standard for hot rolled steel plate or steel strip (GB 709-88).
First of all, the material used for hot rolled steel plate or strip (GB 709-88) should adhere to chemical standards. This includes its carbon content, sulfur content, and phosphorus content. Carbon content must not exceed 0.08%, sulfur content must not exceed 0.035%, and phosphorus content must not exceed 0.050%. Steel products with chemical components above the limits of GB 709-88 are strictly not allowed to be used as construction materials.
In addition to the above, mechanical properties of hot rolled steel are also defined in GB 709-88. For example, tensile strength, yield strength, and elongation must meet certain standards. Plate, which is defined as a rolled steel product with a thickness more than or equal to 4.75mm, must have a tensile strength of not less than 375 MPa and a yield strength of not less than 245 MPa. For strip steel, it must have a tensile strength of not less than 275 MPa and a yield strength of not less than 215 MPa. Furthermore, the elongation of plate and strip steel must also reach 17-21% and 15-20% respectively.
Finally, the surface quality and size of hot rolled steel plate and strip steel are also emphasized. In GB 709-88, the surface of the two types of steel is divided into three categories: ordinary surface, improved surface and superior surface. Among them, the superior surface must reach a ratio of 1:1 for surface roughness, and strip steel must also be able to meet the relevant requirements. In terms of size, the width of strip steel should be between 60-700mm and the length must be between 2000-13000mm; whereas thick steel should have a width of 90-1400mm and length between 2000-13000mm.
In conclusion, the hot-rolled steel plate and steel strip (GB 709-88) provide a useful guideline for the production of hot-rolled steel products. By adhering to the standards, quality and safety of hot rolled steel products can be assured.
