Welding process of semi martensitic stainless steel pneumatic ball valve seat Forging At forging temperature, 17-4PH steel has poor plasticity, large deformation resistance and is prone to cracks. Forging temperature shall be strictly controlled. The initial forging temperature is 1180 ℃, and the final forging temperature is 1010 ℃. Blank heating 3~3 After 5h, the temperature reached 1230 ℃, and the first heat forging was carried out after discharging, no abnormality was found. The second heat forging was carried out after 0.5 h of reheating, and no abnormality was found. Level at 900~950 ℃ to prevent flash cracks. In addition, a punch shall be used in the forging process, and the punch shall have a certain taper. In order to increase the reaming effect, several punches can be used together.

Pneumatic regulating butterfly valve is a kind of valve (valve plate) rotating around a fixed axis perpendicular to the channel. It is composed of a piston type double acting or single acting (spring return type) pneumatic actuator and butterfly valve. According to the structure, it can be classified into medium linear structure, eccentric elastic seat sealing structure, and three-dimensional eccentric multi-level elastic sealing structure. It belongs to rotary high-performance regulating or shut-off valves. Equipped with electro pneumatic valve positioner or solenoid valve, air filter pressure reducer, limit switch (valve position indicator), it can realize proportional regulation and two position cut-off control of fluid medium in process pipeline, so as to achieve automatic control of flow, pressure, temperature, liquid level and other parameters of fluid medium. It is widely used in gas, turbid liquid, thick slurry, ash powder, suspended particles and other media.