Blind plate flange (blind flange) also known as blind plate, the correct name is called flange cover. Is a flange with no holes in the middle for sealing the pipe plug. There are many types of sealing faces, including plane, convex, concave, tenon, ring joint. One of its functions is to seal the end of the pipe, and the other is to facilitate the removal of sundries in the pipeline during maintenance. As far as sealing effect is concerned, it has the same function as head and pipe cap. But there is no way to remove the head, and the flange blind plate is bolted and easily removed. Flange blind plates are made of carbon steel, alloy steel, stainless steel, plastic, etc.
Weld neck pipe flanges is a flange that connects steel pipe, fittings, etc into flanges through fillet welds to equipment or pipes, just like plate flanges. The weld form is different: the weld form between the flange and the pipe is fillet weld, but the weld form between the flange and the pipe with neck butt welding is the circumferential weld; the material is different: the material of the flange with neck is machined by the ordinary steel plate which meets the requirement of thickness, while the material of the flange with the butt welding with the neck is mostly machined by forging steel; nominal pressure is different: nominal pressure of flange with neck is 0.6-4.0MPa, and nominal pressure of flange with neck butt welding is 1–25MPa grade.