Before the construction of steel structure, it is necessary to do the corresponding work well. In this way, while improving the construction efficiency, it can guarantee its quality. Among them, it needs to do a good job in the early stage. What work should be done?

　　1.Joint design: the unilateral clearance of the joint of Guiyang steel structure shall be controlled within 0.08-0.2 mm, and the length of the weld shall not be more than 30 mm generally. 

　　2. surface treatment: use alkaline solution or metal cleaning solution to clean the oil stain and other dirt on the welding joint of steel structure, and then use scraper (or coarse sandpaper, or copper brush, or wire brush) to scrape the insulation layer on the surface of the welding joint.

　　3. welding of copper bar and aluminum bar (or copper wire and aluminum wire): use alkaline solution or metal cleaning solution to clean the oil stain and other dirt at the welding position, and then use copper brush (or wire brush, or scraper, or coarse sandpaper) to scrape the insulation layer on the surface of the joint welding position.