Stainless steel manholes consist of a cylindrical section fixed to the container body and a flange connected to the cylinder, along with a cap sealing the flange. On the contact surface between the flange and the cap, there is a convex surface on the cap and a ring or box-shaped raised rib on the flange that matches the convex surface and extends to the ends. The convex surface of the product and the flange form a cavity within the range of the ribs, and a sealing pad is placed inside the cavity. This manhole boasts excellent sealing performance. The beneficial effect of this product is that by installing the manhole welding frame on the manhole flange cover, the welding of the manhole short section to the shell can be completed through automatic welding, thereby reducing the labor intensity of welders and improving welding efficiency.