company news about The pressure rating of the flange

According to ASME B16.5, steel flanges have 7 pressure levels: Class150-300-400-600-900-1500-2500.

The pressure rating of the flange is very clear. The flange of Class300 can withstand greater pressure than that of Class150 because the flange of Class300 needs to be made with more materials to withstand greater pressure. The pressure rating of the flange is expressed in pounds, and there are different ways of expressing a pressure rating. For example, 150Lb, 150Lbs, 150#, and Class150 have the same meaning.

However, the pressure capacity of the flange is affected by many factors. For example, the same flange, when the ambient temperature is different, the pressure bearing capacity of the flange is also different. When the ambient temperature rises, the pressure-bearing capacity of the flange decreases. For example, the flange of Class150 has a pressure bearing capacity of 270 PSIG at room temperature, a pressure bearing capacity of 180 PSIG at 400°F, a pressure bearing capacity of 150 PSIG at 600°F, and a pressure bearing capacity of 75 PSIG at 800°F. In other words, when the pressure drops, the temperature is allowed to rise, and vice versa. And because the flange can be made of different materials, such as stainless steel, cast iron, ductile iron, carbon steel, etc., each material has a different pressure rating.