Structural characteristics, materials, inspection, and transmission of high-pressure shut-off valves

Structural characteristics, materials, inspection, and transmission of high-pressure shut-off valves

1、 Performance of High Pressure Stop Valve:

Due to the high-pressure casting of the cut-off valve seat channel, its variation is proportional to the valve disc stroke. The valve stem of the high-pressure shut-off valve has a short opening and closing stroke and reliable shut-off function. In addition, as the variation of the valve seat channel is proportional to the stroke, it is very suitable for adjusting the flow rate of the valve disc. Therefore, this type of globe valve is very suitable for use as a cut-off or regulating and throttling valve. Due to the small opening and closing stroke of the valve disc of the cast glove valve, the sealing surface can withstand multiple opening and closing, making the glove valve very suitable for situations that require frequent opening and closing, and can be used for most media. Traffic system. Globe valves are widely used in industries such as petrochemicals, electricity, metallurgy, urban construction, and chemical engineering.

2、 Structural characteristics of high-pressure casting glove valve:

(1) The national standard flange connection, socket welding connection, butt welding connection, and threaded connection globe valve series are conventional products designed with reference to national standards. The cast steel globe valve series is lightweight and flexible, with a reasonable structural design, stable performance, reliable quality, and easy installation and operation.

(2) Spray weld hard alloys of different hardness on the sealing surfaces of the valve disc and seat. Reliable sealing, high hardness, wear and high temperature resistance, excellent scratch resistance, and long service life.

(3) The heat-treated valve stem has excellent scratch resistance and wear resistance.

(4) Different connection methods can be used to meet different pipeline requirements, pipeline flange standards, flange sealing surface shapes, and meet different engineering and user requirements.

3、 Selection of Sealing Materials for High Pressure Casting Glove Valves:

Carbon steel globe valve: valve disc 13Cr, valve seat WCB+HF, WC6+HF or LCC+HF, with a hardness difference of HB ≥ 50 between the two. The spray welding process is strictly carried out in accordance with the spray welding process specifications.

Stainless steel globe valve: butterfly plate 304 or 316, seat OCr18Ni9+HF or OCr17Ni12Mo2+HF, with a hardness difference of HB ≥ 50 between the two. The sealing surface of the valve disc and seat has high hardness, is resistant to erosion and corrosion, and strictly follows the hot spray welding process specifications.

4、 High pressure casting glove valve material:

1. The valve body and cover are made of WCB, WC6, LCC, OCr18Ni9 or OCr17Ni12Mo2 materials. The above valve materials are strictly selected in accordance with GB/T 12224 "General Requirements for Steel Valves" and relevant valve material standards, and have a guaranteed service life. The casting materials include GB/T12229 "Technical Conditions for Carbon Steel Castings for General Valves", GB/T12230 "Technical Conditions for Stainless Steel Castings for General Valves", and JB/T7248 "Low Temperature Steel". Meet the standard requirements specified in the Technical Conditions. Casting requirements. For valves Cast steel undergoes heat treatment according to standard requirements, and its mechanical properties meet the standard requirements. Perform non-destructive testing on pressure resistant cast steel, following the standard JB/T6440 "Radiation Testing of Valve Pressure Resistant Cast Steel Parts". All pressure resistant forgings comply with the requirements specified in JB4726-4728 "Steel Forgings for Pressure Vessels". All report forms have been archived and can be inspected by the buyer during the valve manufacturing process.

2. The valve stem material is 13Cr, 304 or 316. Provide relevant valve standards and mechanical performance report forms (tensile test, hardness test) for valve stem materials, and conduct chemical analysis based on heat treatment and corresponding report forms if necessary. All report forms have been archived and can be inspected by the buyer during the valve manufacturing process.

5、 Inspection and Testing of High Pressure Casting Glove Valves

1. Testing standards

The valve inspection and testing comply with JB/T9092 and GB/T12224 standards. Perform shell pressure testing before valve surface treatment and painting.

2. Valves must undergo 100% pressure testing before leaving the factory. The valve pressure test should include at least the following contents:

——Shell test, upper seal test, low-pressure gas seal test, high-pressure water seal test, and other tests specified in the specifications.

After the experiment is completed, discharge the test medium from the valve body.

4. Conduct 100% X-ray inspection on all butt welds. For pressure components of valves with a pressure rating above PN160, X-ray inspection should be conducted in accordance with JB/T6440.

5. Product users reserve the right to conduct inspections when necessary.

6、 High pressure shut-off valve transmission device:

1. According to the operating conditions of the valve, the valve operating mechanism must have sufficient torque and stiffness.

2. The parts connected to the operating mechanism housing bracket and valve body must have sufficient rigidity and strength.

3. The maximum force on the handwheel of the manual operating mechanism is 35Kgf (under any working condition). The valve drive mechanism must be unobstructed, without jumping, inaccurate, and the entire stroke must be smooth.