Introduce the anti-corrosion methods of SMC solenoid valves and their components separately

Introduce the anti-corrosion methods of SMC solenoid valves and their components separately

The corrosion of SMC solenoid valves is usually understood as the damage to the valve metal material under chemical or electrochemical environmental conditions. Due to the phenomenon of "corrosion" occurring in the spontaneous interaction between metals and the surrounding environment, how to isolate metals from the surrounding environment or use more non-metallic synthetic materials has become a common concern for people.

The corrosion and damage of metals have a significant impact on the lifespan, performance, and service life of valves. The mechanical and corrosive factors greatly increase the total wear of the contact surface on the metal. The total amount of wear on the friction surface of the valve during operation. During the operation of the valve, the friction surface is worn and damaged due to the simultaneous mechanical action and chemical or electrochemical interaction between the metal and the environment. For valves, the complex working climate conditions of their pipelines; The presence of hydrogen sulfide, carbon dioxide, and certain organic acids in oil, natural gas, and reservoir water media increases the destructive power on their metal surfaces, leading to rapid loss of working ability.

Due to the fact that the chemical corrosion of metals depends on temperature, mechanical load on the friction parts, the stability of sulfides and their acid resistance contained in lubricating materials, the duration of contact with the medium, the catalytic effect of metals on the nitriding process, and the conversion rate of molecules of corrosive substances on metals. Therefore, the anti-corrosion methods (or measures) of metal valves and the application of synthetic material valves have become one of the current research topics in the valve industry.

1、 The anti-corrosion of metal valves can be understood as coating a protective layer (such as paint, pigment, lubricating material) on the metal valve to protect it from corrosion, so that the valve is not corroded during manufacturing, storage, transportation, or all processes of its use

The method of anti-corrosion for metal valves depends on the required protection period, transportation and storage conditions, valve construction characteristics and materials, and of course, the economic effect of removing anti-corrosion should be considered.

There are four main methods for anti-corrosion of metal valves and their components:

Place volatile corrosion inhibitors into the atmosphere of steam (wrapped in masking paper and blown to suppress air flow through the product chamber).

Utilize hindered water and alcohol solutions

Apply a thin layer of anti-corrosion (protective) material to the surface of the valve and its components.

Apply a thin layer of hindered film or polymer onto the valve and its components.

(Note: Currently, valve companies widely use lubricating materials and water-resistant solution flow to prevent corrosion.)

Application of SMC solenoid valve

Synthetic material valves, in many corrosive working conditions, rely on metal valves for their corrosion resistance, followed by their net weight. As for their strength, it depends on the shape, arrangement, and quantity of the reinforcing fibers. Generally speaking, the higher the percentage of fibers, the stronger the synthetic material. In valve applications, the weight content of fibers generally ranges from 30% to 40%, and their chemical stability is mainly determined by the resin properties of the encapsulated fibers in the final product. In synthetic material valves, the solid polymer body can be either thermoplastic (such as PVC polyvinylidene fluoride, PPS polyphenylene sulfide) or thermosetting resin (such as polyester, ethylene, and epoxy resin). Thermosetting resins maintain their strength properties in a medium temperature state compared to thermoplastic plastics (i.e. thermosetting resins have a higher thermal deformation temperature). (Note: In the operating conditions, the determination of the thermal resistance of synthetic materials is called the hot deformation temperature.).

At present, the synthetic material for chemical process valves is ethylene based epoxy resin (thermoplastic material), and its reinforcing fibers are chopped glass fiber (1/4 inch long) and chopped graphite fiber (1/4 inch long). The following table compares the performance of commonly used synthetic materials with the performance of corrosion-resistant metals.

Glass reinforced ethylene based graphite reinforced ethylene based graphite reinforced

Note: NA means not applicable (or invalid)

From a surface analysis, glass and graphite reinforced synthetic materials have lower tensile strength compared to metals. Therefore, the parts of synthetic material valves that are subjected to high stress should have thicker cross-sections and reinforced ribs to achieve the same performance as metals.

Due to the corrosion resistance, high strength, and lightweight of synthetic material valves, they have become a cost-effective option for valve products in many corrosive conditions of metal or fiberglass reinforced plastic pipeline systems. The prospect of using synthetic material valves in chemical process conditions.

In the valve industry, the use of organic and synthetic materials is no longer the traditional concept of metal and non-metal valve materials. Ceramics (which can increase the operating temperature of valves from 400 ℃ to over 1200 ℃), plastics (which have the characteristics of rust and corrosion resistance), synthetic materials (which have the characteristics of corrosion resistance, light weight, and high strength), and memory alloys (valves manufactured using the reversibility and high elasticity of shape memory alloys or temperature memory alloys). New materials are being developed to produce a large number of high-performance valve products. The development of new technologies has made it possible to apply various engineering materials to the valve manufacturing industry