The number of key parts of the gate valve is small, the structure is relatively simple, the machining accuracy of most specifications is not high, and the outside is relatively rough, which gives people an impression of being a simple machine. In fact, the cardiovascular sealing position of the gate valve is extremely high-precision, the "three degrees" (flatness, smoothness, strength) of the sealing surface are very high, and the degree of fit of the sealing pair formed by the two sealing surfaces is very high. All need to do a zero-to-zero to achieve zero leakage in the air-tightness test. This kind of non-smooth standard to ensure the high-precision zero-to-zero regulation of the heart is a very big processing problem in the production and processing of gate valves.
Step 1: Oil circuit board manufacturing
Gate valve oil circuit board (casting, sealing surface surfacing)
Purchase of castings (according to specifications) ➱ incoming inspection (according to specifications) ➱ surfacing grooves ➱ ultrasonic testing (according to drawings) ➱ surfacing and post-weld heat treatment ➱ deep processing ➱ grinding and sealing surface ➱ sealing surface strength inspection, color flaw detection.
Step 2: Manufacturing process of the gate valve main parts
A. The main parts that need surfacing welding and sealing surface, such as the piston valve, high-pressure gate valve, etc.
Purchase of raw materials (according to specifications) ➱ incoming inspection (according to specifications) ➱ making blanks (garden steel or steel castings, according to the processing technology regulations of engineering drawings) ➱ initial processing of ultrasonic inspection surfaces (when specified in drawings) ➱ initial processing of surfacing grooves ➱ Overlay welding and post-weld heat treatment ➱ Deep processing everywhere ➱ Grinding sealing surface ➱ Sealing surface strength inspection, coloring flaw detection.
B. Valve seat
Purchase of raw materials (according to specifications) ➱ In-plant inspection (according to specifications) ➱ Making blanks (round steel or steel castings, according to the processing technology of engineering drawings) ➱ Preliminary processing of surfacing grooves ➱ Surfacing and post-weld heat treatment ➱ Deep processing of each Part ➱ Cutting inner hole ➱ Valve seat surface treatment (nitriding, heat treatment, organic chemical coating) ➱ Final solution (grinding, polishing, cutting, etc.) ➱ Grinding the sealing surface ➱ Sealing surface strength inspection, coloring and flaw detection.
C. The main parts that do not need surfacing welding, sealing surface, etc.
Purchase of raw materials (according to specifications) ➱ factory inspection (according to specifications) ➱ making blanks (garden steel or steel castings, according to the processing technology regulations of engineering drawings) ➱ initial processing of ultrasonic inspection surfaces (when specified in drawings) ➱ deep processing everywhere.
Step 3: standard parts production
Standard parts manufacturing specification DL439-1991.
Purchase of raw materials (according to specifications) ➱ incoming factory inspection (according to specifications) ➱ making blanks (garden steel or steel castings, according to the processing technology regulations of engineering drawings) and sampling and carrying out required inspections ➱ preliminary processing ➱ deep processing ➱ spectrometer inspection.
Step 4: Assembly Process
Received parts ➱ Clear and clean ➱ Rough installation (according to drawings) ➱ Pressure test (according to engineering drawings, processing technology) ➱ After passing, disassemble, wipe clean ➱ Final installation ➱ Adjust with electric equipment or electric actuator (for electric control valve )➱Paint Packaging➱Shipping.
