What are the advantages of using sandblasting machine to process the surface treatment of precision valves?

The surface treatment of precision valves by sand blasting machine can improve the quality of valves in many aspects, such as cleanliness, roughness and performance optimization. The following are the specific benefits and principles:

First, improve the surface cleanliness and remove impurities and defects.

Thoroughly remove surface pollutants: The sandblasting machine can effectively remove impurities such as scale, rust, oil stain and welding residue on the valve surface through high-speed sand impact. For example, the residual molding sand or oxide layer produced by heat treatment during valve casting can expose the metal matrix after sandblasting to avoid impurities affecting subsequent assembly or sealing performance.

Eliminate micro-defects: For key parts such as sealing surface and thread of precision valve, sandblasting can remove tiny burrs and scratches on the surface, reduce stress concentration points and avoid leakage or wear caused by defects.

Second, optimize the surface roughness and enhance the functionality

Control the surface texture to meet the sealing requirements;

For valve sealing surfaces (such as valve seat and valve core), sandblasting can form uniform rough texture, which can better fill the gap when contacting with sealing gasket and improve sealing performance. For example, when the roughness is controlled at Ra 3.2-6.3μm, the sealing surface has a higher fit.

Sand blasting treatment of non-sealing surface (such as the outside of valve body) can increase surface friction, prevent slipping during assembly, and facilitate subsequent painting or coating adhesion.

Avoid problems caused by excessive smoothness: if the surface is too smooth (such as mirror polishing), the local contact pressure of the sealing surface may be uneven due to "mirror effect", which will reduce the sealing reliability; The microscopic concave-convex structure formed by sandblasting can evenly disperse the pressure and improve the stability.

Third, improve material performance and prolong service life.

Surface hardening and stress adjustment;

When steel shot, ceramic sand and other media are used for sand blasting, high-speed impact will cause plastic deformation on the metal surface and form a compressive stress layer (such as austenitic stainless steel valves), which will improve the fatigue strength and corrosion resistance. For example, after sandblasting, the surface hardness of the ball valve can be increased by 10%-15%, and the erosion wear can be reduced.

For welded valve parts, sandblasting can eliminate local welding stress and reduce the risk of cracking.

Improve corrosion resistance: after removing scale and impurities, the passivation film of stainless steel valve can be formed more evenly, and the intergranular corrosion resistance can be enhanced; After sandblasting, the oxide layer on the surface of zinc coating can be removed, which is convenient for subsequent passivation and improves the protective effect of zinc coating.

Fourth, improve the machining accuracy and consistency

Precise control of surface treatment effect: the sandblasting machine can realize the fine treatment of different areas by adjusting the parameters such as sandblasting pressure, sand particle size and injection angle. For example, automatic sandblasting equipment (such as rotary sandblasting machine) can be used to ensure uniform surface treatment and avoid the randomness of manual operation for small diameter holes and complex inner cavities of valves.

Requirements for fitting precise dimensions: The surface roughness of sandblasting treatment is controllable, and the geometric dimensions of the valve (such as fitting tolerance) will not be significantly changed, so it is suitable for surface treatment of high-precision valves (such as regulating valves with nominal diameter ≤DN50).

Five, environmental protection and efficiency advantages

Replacing chemical cleaning and reducing pollution: Compared with pickling, electrolytic polishing and other processes, sandblasting treatment does not need strong acid and alkali, reducing wastewater discharge and meeting environmental protection requirements.

Efficient batch processing: For mass production of valves, automatic sandblasting machine can realize assembly line operation (such as through sandblasting machine), and the single processing time is short (usually 5-15 minutes/piece), thus improving productivity.

matters need attention

Media selection: Choose the sand type (such as white corundum, glass beads and plastic sand) according to the valve material (such as stainless steel, cast iron and copper alloy) to avoid the pollution of sand material (such as carbon steel sand used in stainless steel valves may lead to iron ion residue and increase the risk of rust).

Parameter optimization: pressure (usually 0.3-0.6MPa) and time should be strictly controlled for sealing surface sandblasting to avoid surface damage caused by excessive sandblasting; Valves with complex structures can be matched with fixtures to ensure consistent treatment of all parts.

Through the fine treatment of sandblasting machine, the surface quality, functional performance and reliability of precision valves can be significantly improved, especially suitable for petrochemical, food and medicine, aerospace and other scenes that require high sealing and corrosion resistance.