AWWA blind flange
AWWA Blind flanges, some are also called blind flanges or pipe plugs. It is a flange with no holes in the middle to seal the pipe opening. The function is the same as the head and cap, except that the blind seal is a detachable seal and the seal of the seal is not ready to be reopened. There are many types of sealing surfaces, such as flat, convex, concave and convex, grooved and ring joints. The material is carbon steel, stainless steel and alloy steel.
The blind plate functions to isolate and cut off, and the function of the head, the cap and the welding plug is the same. Because of its good sealing performance, it is generally a reliable means of isolation for systems that require complete isolation. A flat plate blind is a solid circle with a handle for a system that is normally isolated. The 8-word blind plate is shaped like a 8 word, one end is a blind plate, and the other end is a throttle ring, but the diameter is the same as the pipe diameter of the pipe, and does not function as a throttle. The 8-word blind board is easy to use. When it needs to be isolated, the blind end is used. When the normal operation is required, the throttle ring end is used, and the installation gap of the blind plate on the pipeline can also be filled. Another feature is that the logo is obvious and easy to identify the installation status.
The production process is mainly divided into three types: forging, casting, and cutting.
Cast flange and forged flange
Casting flange, the shape of the blank is accurate, the processing volume is small, the cost is low, but there are casting defects (pores, cracks, inclusions); the internal flow of the casting is poor (if it is a cutting part, the streamline type is worse);
Forged flanges generally have lower carbon content than cast flanges and are less prone to rust. Forgings have better streamlined shape, denser structure and better mechanical properties than cast flanges;
If the forging process is improper, the grain will be large or uneven, and the hardening crack will occur. The forging is higher than the casting flange.
Forgings can withstand higher shear and tensile forces than castings.
The advantage of the casting is that it can produce a more complicated shape, and the cost is relatively low;
The advantage of the forging is that the internal structure is uniform, and there are no harmful defects such as pores and inclusions in the casting;
Different from the production process, the difference between the cast flange and the forged flange, such as the centrifugal flange, is one of the cast flanges.
Centrifugal flange is a precision casting method production flange. This kind of casting is much thinner than ordinary sand casting structure, and the quality is improved a lot. It is not easy to have problems such as loose structure, pores and trachoma.
First of all, we need to understand how the centrifugal flange is produced and processed by centrifugal casting to make a flat welding flange.
The product is characterized by the following process steps:
1 The selected raw material steel is smelted in a medium frequency electric furnace to make the molten steel temperature reach 1600-1700 ° C;
2 preheating the metal mold to 800-900 ° C to maintain a constant temperature;
3 start the centrifuge, and inject the molten steel in step 1 into the metal mold after preheating in step 2;
4 castings are naturally cooled to 800-900 ° C for 1-10 minutes;
5 Cool with water to near normal temperature, demoulding to remove the casting.
