At first glance, the valve parts are not many, the structure is simple, the accuracy is general, and it is a simple part in the mechanical industry, but the core sealing part of the valve is particularly high. Valve manufacturing process is complex, technical difficulty is also large, which process characteristics we need to pay attention to?

1. Make materials

Due to the wide variety of valve specifications, such as general valves have gate valves, globe valves, check valves, ball valves, butterfly valves, hydraulic control valves; Industrial valves have solenoid valves, regulating valves, pressure reducing valves, high temperature and high pressure valves, low temperature valves and other special valves, are used in various fields of the national economy, the use of the occasion is very different, such as high temperature and high pressure, low temperature cryogenic, flammable and explosive, highly toxic, strong corrosive medium and other working conditions, the material of the valve put forward harsh requirements.

In addition to cast iron, carbon steel, alloy structural steel, but also a large number of CrNi stainless steel, CrMoAl nitrided steel, CrMoV heat resistant steel, CrMnN acid resistant steel, precipitation hardening steel, duplex stainless steel, low temperature steel, titanium alloy, Monel alloy, Inconel alloy, Hasselloy and G0CrW carbide. The casting, welding and processing properties of these high alloy materials are very poor, which brings great difficulty to the manufacturing process. In addition, most of these materials are high-alloy, high-strength, high-hardness precious materials, from the material selection, material preparation, procurement there are many difficulties. Some materials are difficult to procure due to the small amount of use.

2. Structure of casting blank

Most of the valve blanks are thin shell castings with complex structure, which not only requires good appearance quality, but also dense internal quality and good metallographic structure, and can not have porosity, shrinkage, sand, cracks and other defects. Therefore, the casting process is complex and the heat treatment technology is difficult. In the machinery industry, the casting difficulty of the valve's pressure thin shell castings is far more complex and difficult than that of other mechanical components.

3. Machining technology

Because most of the high strength, high hardness, high corrosion resistance materials are not good cutting performance, such as high alloy stainless steel, acid resistant steel have high toughness, high strength, poor heat dissipation, chip viscosity and work hardening tendency and other shortcomings, it is difficult to achieve the required dimensional accuracy and finish, to machining tools, processes and equipment bring certain difficulties. In addition, the requirements of the valve sealing surface in processing accuracy, matching Angle, finish and matching sealing pair are also very high, which brings great difficulty to machining.

4. Process arrangement of valve parts

The main parts of the valve are not many, the structure is relatively simple, the processing accuracy of most sizes is not high, and the external is relatively rough, which gives a person the impression of a simple machine. In fact, the heart sealing part of the valve is its own, and the "three degrees "(flatness, finish, hardness) of the sealing surface is very high, and the anastomosis of the sealing pair composed of the two sealing surfaces must reach zero to zero to meet the zero leakage of the airtight test. This rough benchmark to ensure the zero to zero requirements of the heart is the major technical difficulty of valve processing.

5. Valve test and inspection

The valve is an important opening and closing, regulating element of the pressure pipeline, and the working conditions of the pressure pipeline are very different, high temperature and high pressure, low temperature and deep cooling, flammable and explosive, highly toxic and strong corrosion. However, the test and inspection conditions of the valve manufacturing can not meet the same requirements of the working conditions, international and domestic valve test standards are at close to normal temperature conditions, with gas or water as a medium for testing. This is a fundamental hidden danger, that is, the normal factory test qualified valve products, in harsh actual working conditions may produce due to material selection, casting quality and seal damage and other problems and difficult to meet the requirements of use, there will be major quality accidents. No wonder some of the old valve experts who have done a lifetime, the older the more restrained, the more dry the more worried.

Read the characteristics of the valve manufacturing process, have you been shocked to it? Increase the knowledge!! What looks like a simple valve is not so easy to manufacture? So, how exactly is the valve manufactured step by step...... Valve manufacturing process

Step: Valve body manufacturing

Valve body (casting, sealing surface surfacing)

Casting purchase (according to standard)? incoming inspection (according to standard)? surfacing groove ? ultrasonic flaw detection (according to the pattern)? surfacing and post-welding heat treatment ? finishing ? grinding sealing surface ? hardness inspection, color detection of the sealing surface.

The second step: valve internal parts manufacturing process

A, need to surfacing sealing surface of the internal parts such as valve disc, seat, etc

Raw materials procurement (according to the standard)? incoming inspection (according to the standard)? Making rough (round steel or forging, according to the technical requirements of the drawings)? rough surfacing groove ? surfacing and post-welding heat treatment ? of each part of the finishing ? grinding sealing surface ? hardness inspection, color detection of the sealing surface.

B, valve stem

Raw materials procurement, according to the standard ? incoming inspection (according to the standard) ? production blank (or round steel forging, according to the drawing process requirement) ? roughing surfacing welding groove ? overlaying welding and heat treatment after welding ? processed by grinding cylindrical ? ? stem surface treatment (nitride, quenching, chemical plating) ? end processing, polishing, grinding, etc.) ? grinding hardness test, penetrant inspection seal face ? seal face.

C, do not need to surfacing sealing surface of the internal parts, etc

Raw material purchase (according to standard)? incoming inspection (according to standard)? Making rough (round steel or forgings, according to the drawing technical requirements)? rough processing of ultrasonic flaw detection surface (when the drawing requirements)? finishing all parts.

Step 3: Fastener manufacturing

Fastener manufacturing standard DL439-1991.

Raw materials purchase (as per standard)? incoming inspection (as per standard)? Make rough (round steel or forgings, according to the technical requirements of the drawings) and take samples for necessary inspection ? rough processing ? finishing ? spectrum inspection.

Step 4: Final assembly

Get the parts ? cleaning and cleaning ? rough assembly (according to the drawing)? water pressure test (according to the drawing and process)? qualified, disassemble, wipe ? final assembly ? and electric assembly or actuator debugging (for electric valve)? paint packaging ? shipping.

Step 5: Product production and inspection process

1, the company purchased various specifications of raw materials.

2. Conduct material testing on raw materials with spectral analyzer, and print out the material testing report for backup.

3. Cutting raw materials with cutting machine.

4. Inspectors inspect the cutting diameter and length of raw materials.

5, the forging workshop for the raw materials forging molding treatment.

6, the inspection personnel to the forming of various dimensions of the blank inspection.

7. The workers are cutting the waste edge of the blank.

8, sandblasting workers on the blank surface sandblasting treatment.

9. The inspectors inspect the surface treatment after sandblasting.

10. The workers carry out blank machining.

11, valve body sealing thread processing -- employees in the process of self-inspection inspectors after the product after processing inspection.

12, valve body connection thread processing.

13, hole processing.

14. Inspectors conduct general inspection.

15, qualified semi-finished products are sent to semi-finished products warehouse.

16. Electroplating of semi-finished products.

17, semi-finished electroplating surface treatment inspection.

18. Inspection of various accessories (ball, stem, sealing seat).

19, assembly workshop for product assembly - assembly line inspectors to inspect the product.

20, after assembly, the product is pressure tested and dried into the next process.

21, the final assembly workshop for product packaging ---- packaging line inspection personnel on the product tightness, appearance, torque inspection. Substandard products are never allowed to be packed.

22, qualified products are bagged and packaged and sent to the finished product warehouse.

23, all inspection records will be classified and stored in the computer for reference at any time.

24, qualified products are sent to home and abroad through containers