Operation of large air separation unit

Lean alloy steel is often used in special pressure-bearing equipment. The alloying elements often added include manganese, silicon, chromium, nickel, molybdenum, vanadium, boron and rare earth elements. Most of silicon and manganese melt into ferrite, only a small amount into cementite, which are commonly used strengthening elements in lean alloy steel. The amount of chromium and nickel is generally small, and the main role of chromium and nickel is to increase the undercooling degree of austenite and refine the microstructure. Part of chromium is dissolved in ferrite and some in cementite, which can improve the stability of cementite. Molybdenum is dissolved in ferrite slightly, and has the effect of solid solution strengthening. It is a strong carbide forming element, which can improve the high temperature strength of steel and improve the temper brittleness.

There must be enough smooth straight pipe sections before and after the flow orifice plate. The distance is 10 times of pipe diameter in front of the orifice plate and 5 times of the pipe diameter behind the orifice plate, and no factors affecting the measurement accuracy (such as pipe joint, etc.) are allowed. The inner surface of the pipe weld should also be ground smooth, and the gasket should not extend into the inner diameter of the pipe. And carefully check the installation direction of the orifice plate, do not install it in reverse. (judgment method: the small exit is the entrance, and the large exit is the outlet)