The GB 905-82 standard which outlines the specifications for cold drawn round steel covers the dimensions, shape, weight, and permissible deviation from the specified dimension and shape of cold drawn round steel products. The applicable materials are carbon steel products, alloy steel products, and stainless steel products, and the applicable range is from φ 3.2 mm to φ 150 mm in diameter.
The standard specifies the requirements for the shape and dimensions of different types of cold drawn round steel, including straight bars (tight skew), round bars (roundness) and sheets (straightness). The allowable deviation from the specified shape and dimension requirements is also specified in the standard. It also covers the allowable tolerances for the three types of round steel products.
The permissible deviation from the dimension specified should not exceed ± 0.1mm in the case of diameter. For other shapes, the respective deviations are generally 0.06mm. In addition, the permissible deviation from the specified weight should not exceed ± 3%.
In addition to the shape and dimension, the standard specifically addresses the surface condition of the cold drawn round steel. The standard stipulates that the surface should be without any blemishes and defects, including holes, grooves, cracks and burrs. The residual scale on the surface should not exceed 0.5mm. The flatness of the surface should meet the requirements specified in the standard.
The standard specifies the requirements for the hardness and property of the round steel as well. The hardness should generally meet the specified requirements. The mechanical properties should also meet the requirements specified in the standard. The composition of the round steel should meet the requirements specified in the corresponding material or strength standard.
The standard also covers the requirements for the testing of cold drawn round steel. The product should be tested for dimensional accuracy, hardness and other physical and mechanical properties. The product should also be tested for any surface defects or imperfections.
The standard stipulates that all the cold drawn round steel products should comply with the requirements and should be marked accordingly. The marking of the products should include the size, material, diameter, surface and other pertinent information. The marking should also indicate the standard to which the products adhere.
