GB 6723-86 Cold-bent Inner Inward Edge Groove Steel
Overview
Cold-bent inner inward edge groove steel (hereinafter referred to as cold-bent steel) is a kind of special steel products with a groove on the inner side of the outer surface of the strip after cold bending. It was developed based on GB13237-82 cold-formed acid-washed steel strip as the substrate and pretreatment techniques. It is mainly used in the manufacture of various building components, such as window frames, doors, shutters, roller shutters, blinds, air-conditioning and ventilation ducts, etc. Cold-rolled acid-washed steel is first cold-rolled, then acid-washed and then further cold-bent and distributed according to the requirements of the shape. The analysis and quality requirements of the cold-bent steel strip and the control technology during manufacture are regulated by GB 6723-86.
Basic requirements
1. The thickness range of cold-formed steel strip can be determined according to the processing performance and size requirements for cold-formed steel sections.
2. The steel grade should be able to meet the corresponding welding performance requirements, or according to the specific application requirements for welding performance.
3. The surface of the cold-bent steel strip should be smooth and clean. There should be no obvious defects such as corrosion, rust, scratch, etch and oil stain on the surface.
4. The acid wash should be clean and smooth, and no obvious discoloration or staining should be visible.
5. For cold-bent inward H-shaped steel, the ratio of the inner height h to the width b should meet the specified requirements.
Control technology
1. The performance of the steel strip should meet the requirements of GB 13237, and the surface should be smooth and clean. When necessary, a sample inspection should be carried out.
2. During the acid wash process, pay attention to the ratio of acid to water, temperature, liquid temperature, and immersion time. The acid solution must be replaced frequently, otherwise affect the strip surface quality.
3. Attention should be paid to the method of acid solution, either soaking in acid solution or spraying.
4. The acid-washed steel strip should be rinsed, degreased and neutralized with alkaline detergent and water before cold-forming, and then dried.
5. During the cold-forming process, special attention should be paid to the control of the gap and the linearity of the rolling passes.
6. The surface of the cold-bent steel strip should be cleaned and inspected after forming.
Quality inspection
1. According to thequality level of hot-rolled steel.
2. Strictly check the tolerance range of the size, the shape and the deviation of the edge groove.
3. Check for any surface defects such as corrosion, rust, and scratch.
4. Inspect the inner height-to-width ratio of the inward H-shaped steel.
Conclusion
GB 6723-86 regulates the quality requirements and process control technology of cold-bent inner inward edge groove steel, ensuring the production of qualified cold-formed steel products and ensuring the basic properties and quality of the products.
