что такое износостойкий шаровой клапан?

In industrial production, valves are crucial components in various piping systems. They cut off or connect the medium in pipes to precisely control fluid flow, pressure, etc. However, in tough conditions like coal chemical or polysilicon projects, ordinary valves are prone to wear and leakage, causing frequent replacement. This increases costs and leads to huge economic loss due to system shutdowns. The wear-resistant ball valve has emerged as a solution, becoming a favorite in many industrial fields.

Among many industrial valves, wear-resistant ball valves stand out for their excellent performance. What makes them so special?

Unlike conventional metal-sealed ball valves with two separate seats, wear-resistant ball valves have an integrated sealing structure. This reduces leak points, just like merging two separate doors into one solid door to eliminate gaps. It prevents medium leakage around the seat, ensuring high-performance during long-term operation and achieving zero leakage. This lays a solid foundation for stable piping system operation.

The ball and seat have good shear self-cleaning ability. During valve operation, the relative motion between them generates shear force to remove dust and other impurities on the sealing surface. It's like using a sharp knife to scrape off dirt, effectively preventing jamming caused by dust-sealed valve pairs. Even when conveying media with much dust, such as coal powder or silicon powder, the valve can operate smoothly without clogging.

The sealing pair is treated with super-wear-resistant alloy technologies like high-velocity spraying and oxy-acetylene spray welding. These technologies form a hard, wear-resistant alloy layer on the ball and seat surfaces. High-velocity spraying uses a high-speed gas flow to accelerate alloy powder particles beyond sound speed, forming a dense, uniform coating on the substrate. Oxy-acetylene spray welding melts alloy powder with an oxy-acetylene flame and sprays it onto the substrate for strong bonding. After treatment, the sealing pair gains high hardness and wear-resistance, lasting several times longer than conventional valves. It's like giving ordinary metal a strong "armor" to resist medium erosion and wear.

After understanding the unique features of wear-resistant ball valves, let's compare them with conventional ones to see their advantages.

Conventional valves use two separate seats with more leak points and gaps for medium transmission, leading to seat wear and seal failure over time. Wear-resistant ball valves' integrated seat structure reduces leak points and medium accumulation, making sealing more stable and reliable. It's like optimizing the valve's interior for a clean, compact design, leaving no place for media to "hide" and ensuring it flows as intended.

Conventional valves often use surface chromium plating or ion nitriding for ball hardening. These methods slightly increase hardness but result in thin hardening layers with limited wear-resistance and short service life. It's like coating the ball with thin "nail polish" that wears off quickly under strong medium impact. Wear-resistant ball valves' sealing pairs are treated with high-velocity spraying and oxy-acetylene spray welding, forming alloy layers with high hardness and moderate thickness (0.3-0.6mm after spraying, 0.2-0.4mm after grinding). This provides excellent wear-and impact-resistance, like a strong "armor" for the ball, enabling long-term good operation in harsh conditions and extending service life.

After comparing wear-resistant and conventional ball valves, let's delve into the manufacturing process of wear-resistant ones to uncover the secrets behind their excellent performance.

Wear-resistant ball valves use various hardening spraying processes, such as nitriding, overlay welding, flame spraying, plasma spraying, and high-velocity spraying. Nitriding involves nitrogen atom infiltration into the metal surface at a certain temperature to form a hard nitriding layer, enhancing wear-and corrosion-resistance but with relatively shallow hardening depth. Overlay welding deposits a thick wear-resistant alloy layer via welding but may cause internal stress and deformation. Flame spraying uses a flame to heat spraying materials to a molten or semi-molten state, then sprays them onto the substrate with a high-speed gas flow to form a coating. Plasma spraying uses high-temperature plasma arcs to melt and accelerate spraying materials for higher-quality coatings with stronger bonding. High-velocity spraying, as mentioned earlier, creates dense, uniform ultra-wear-resistant coatings and is a relatively advanced hardening technology. Each process has its characteristics, and choosing the right one based on operating conditions and valve material is key to achieving excellent wear-resistance.

Coating thickness and anti-delamination performance are a pair of contradictions. Thicker coatings are more wear-resistant but have higher stress and lower bonding strength, making them prone to delamination. To address this, after plasma or high-velocity spraying, the coating thickness is controlled at 0.3-0.6mm and then ground to 0.2-0.4mm. This ensures sufficient wear-resistance while reducing delamination risk, allowing wear-resistant ball valves to maintain good performance during use.

By exploring the manufacturing process, we gain a deeper understanding of the excellent performance of wear-resistant ball valves. How is this high performance achieved in their sealing pair design?

The sealing structures of the front and rear seats in wear-resistant ball valves differ but both achieve bidirectional sealing, with leakage grades better than Class VI. This means effective medium leakage prevention in both directions, far exceeding general standards. It's like installing double insurance for the valve to firmly hold the sealing line under positive and negative medium pressure, ensuring safe and reliable piping system operation.

The wear-resistant ball valve, including the metal-hard-sealed type, has a unique arc-shaped seat design offering good sealing, self-grinding, and scraping cleaning functions. The arc-shaped seat better conforms to the ball's shape for precise sealing when the valve is closed. During medium flow, the relative motion between the seat and ball self-corrects minor sealing surface damage. Additionally, the arc-shaped seat scrapes off impurities on the ball surface, improving the valve's self-cleaning ability and sealing reliability. It's like equipping the valve with a "little assistant" for constant cleaning and maintenance of the sealing surface.

After understanding the sealing pair design, let's look at the actual performance of wear-resistant ball valves. Their application fields and material selection are key to their wide use.

Wear-resistant ball valves suit harsh conditions in petroleum, chemical, power, and metallurgy industries, such as oil pipelines with sand impurities, strong-abrasive media transportation in chemical polysilicon projects, dust-transport pipes in power dry-dedusting systems, and high-wear-resistant medium pipelines in metallurgy. They're like "all-round warriors," showcasing excellent performance in complex industrial environments and ensuring piping system operation.

Based on different media and conditions, wear-resistant ball valves can be made of various materials to suit water, steam, oil, nitric acid, acetic acid, oxidizing media, urea, etc. This gives them strong versatility and adaptability. Whether facing acidic, alkaline, or neutral media, or high-temperature, high-pressure, normal-temperature, or normal-pressure environments, suitable materials can be found to ensure valve service life and performance.

Besides the above-mentioned aspects, metal-hard-sealed wear-resistant ball valves have unique advantages.

The ball and seat of metal-hard-sealed wear-resistant ball valves use a metal-to-metal sealing method. Compared to soft sealing, it has better high-temperature resistance and stable sealing performance in harsh conditions. To ensure reliable sealing under various temperatures and pressures, multiple advanced hardening technologies like high-velocity spraying, nickel-based spray welding, special surface hardening, and hard alloy spray welding are used. These make the ball and seat surface hardness reach over HRC60, up to HRC74, with sealing surface material heat resistance up to 540℃, up to 980℃, and material bonding strength over 10000 PSI. They also have excellent wear-and impact-resistance. It's like building a solid metal fortress in the valve's core to defend against harsh conditions and ensure piping system safety.

Suitable for various pipelines from Class150 to 1500 LB, they cut off or connect media in pipes. This means stable operation under different pressure grades, whether in medium-and low-pressure or high-pressure systems, providing reliable shut-off control and safeguarding complex industrial piping systems.

In summary, wear-resistant ball valves play a crucial role in many industrial fields due to their reliable sealing, unique shear self-cleaning function, super-wear-resistant alloy technology, and wide applicability. They solve the problem of easy wear and leakage of conventional metal-sealed ball valves in harsh conditions. With advanced manufacturing processes and design structures, they achieve long-life, high-performance operation, ensuring the safety, stability, and efficiency of modern industrial production. Wear-resistant ball valves are expected to expand their application fields and create more value for industrial production with technological progress.