Integrated fixed cover structure and manufacturing method thereof

The invention provides a one-piece fixed cover structure and a manufacturing method thereof.The two ends of a one-piece fixed cover are provided with an inlet header and an outlet header respectively, the one-piece fixed cover comprises an upper cover body and a lower cover body, the inner wall of the upper cover body is provided with an upper heating surface, and the inner wall of the lower cover body is provided with a lower heating surface; the upper heating surface and the lower heating surface are respectively enclosed by seamless steel pipes side by side, the lower heating surface is respectively formed by connecting an inner-layer pipe and an outer-layer pipe through a bent pipe, the outer surface of a lower side pipe at the turning part of the upper heating surface is subjected to surfacing welding, the pipes are filled and sealed by wear-resistant alloy round steel, spoilers are arranged in the pipes, and the spoilers are connected with the inner-layer pipe and the outer-layer pipe. The fixed cover i