Characteristics of blind flanges and fastener matching

　　Blind flanges are usually flanged and butt welded flanges. The blind flange has no large caliber. In the actual production and sales, or the proportion of flat welding products accounted for a lot. Blind flange and butt-welded large flange have different structure and use range, and their characteristics and advantages will be different. Therefore, ASTM B16.5 RF 304/316 Stainless Steel Blind Flange should be used in different areas to ensure that blind flange plays an important role. Blind flange has poor steeliness, which is suitable for pressure P < 4 MPa, and rigid, which is suitable for high pressure and temperature.

　　There are three types of flange sealing surface: flat sealing surface, which is suitable for situations with low pressure and non-toxic medium; concave and convex sealing surface, which is suitable for situations with slightly higher pressure; mortise sealing surface, which is suitable for situations with flammable, explosive, toxic medium and high pressure. Blind flanges are often used together with fasteners in application. The following are their application characteristics: first, the mechanical performance pattern of blind flanges should be stolen along the rolling direction on the billet after heat treatment, so that the cutting position is: if the diameter of the billet is not greater than 40 mm, then it should be sampled at the center; if the wool is not bigger than 40 mm, it should be sampled at the center. When the diameter of the slab is greater than 40mm, the sample is taken at the center of 1/4 diameters. Equal length stud studs and all threaded studs should be tested in batches. The nuts should be tested according to the batch hardness test, and the materials for special fasteners should have the material qualification certificate of the manufacturer.