As the foundation for determining valve performance, life and stability, valve materials bear the heavy responsibility of ensuring the safe, efficient and continuous operation of the system. From traditional metals to emerging non-metals, various materials have their own strengths under different working conditions and jointly build a reliable fluid control line of defense.

 

 

①Stainless steel: a model of corrosion resistance

The stainless steel family has a variety of components, with iron as the matrix and a variety of alloy elements. 304 stainless steel, with a chromium content of about 18% - 20% and a nickel content of 8% - 10.5%, performs well in conventional environments. Chromium promotes the formation of a dense chromium oxide film on the surface, which effectively resists atmospheric oxidation, freshwater erosion and general weak acid and alkali corrosion. It is widely used in valve manufacturing in the fields of food processing, building water supply and drainage, etc., to ensure the purity of the medium and the durability of the pipeline.

316 stainless steel goes a step further, adding an additional 2% - 3% of molybdenum, which greatly enhances the tolerance to chloride ions. In harsh environments such as marine engineering and chemical coastal facilities, it faces seawater erosion and chlorine-containing chemical medium erosion, giving long life to valves at key nodes of cooling systems and pipeline transportation.

However, when the service temperature rises above 500°C, its microstructure is thermally disturbed, and its strength and creep resistance gradually deteriorate, limiting its application in high temperature extreme scenes.

 

② Copper alloy: a versatile all-rounder with balanced performance

Copper-zinc alloy (brass) is favored for its outstanding cost-effectiveness and good processing performance. It is soft in texture, smooth in cutting, and easy to shape complex valve structures. It is widely popularized in the field of low-pressure plumbing valves, taking into account functionality and decorativeness, and meeting the water needs of homes and general buildings.

Copper-tin alloy (bronze) has a long history. Tin element refines grains and improves strength. Phosphor bronze has self-lubricating properties due to the addition of phosphorus element, making it the preferred choice for valve sealing surfaces and bearing components. It ensures stable operation between friction pairs in ship power systems and precision instrument valves and withstands frequent action wear.

Aluminum bronze has unique corrosion resistance and is especially suitable for seawater and sulfur-containing industrial environments. It resists salt spray, seawater impact and microbial corrosion in port machinery and marine equipment hydraulic valve systems, and maintains long-term stable operation of equipment. However, compared with some high-strength alloy steels, copper alloys have a lower overall hardness and are prone to deformation under high pressure and high load conditions. Long-term corrosion by strong acids and alkalis can also cause structural damage.

 

③ Nickel-based alloys: The master of high temperature and high pressure

The core component of nickel-based alloys is more than 50% nickel, and is compounded with high melting point and strong corrosion-resistant elements such as chromium, molybdenum, and cobalt. Inconel series, such as Inconel 625, chromium and molybdenum synergistically enhance high-temperature oxidation resistance and sulfurization ability, maintain the stability of the material structure at high temperatures above 600°C, and the mechanical properties decay slowly. Aerospace engine fuel control and oil refining high-temperature cracking unit valves rely on it to ensure reliable operation in extreme thermal environments.

The Hastelloy series focuses on highly corrosive working conditions. Hastelloy C-276 is not afraid of strong acid systems such as hydrochloric acid and sulfuric acid and complex mixed corrosive media. Chemical hydrometallurgical core reactors and key pipeline valves use it to resist erosion and strictly adhere to process safety.

However, the high cost of nickel-based alloys is due to the addition of rare metals and complex preparation processes. Processing and molding require special casting and welding technology matching, which restricts large-scale conventional applications.

④ Titanium and titanium alloys: representatives of lightweight and high performance

The density of titanium is only about 60% of that of steel, but it can achieve medium-to-high strength levels through alloying, with outstanding specific strength advantages, which meets the rigid demand for weight reduction in aerospace. Aircraft hydraulic boosters and life-support oxygen supply system valves are lightweight and efficient due to titanium alloys; its corrosion resistance originates from the rapid formation of a stable TiO₂ protective film on the surface, which is "indestructible" in oxidizing, neutral media, seawater, and the strong corrosive environment of the chlor-alkali industry, and the life of valves in large-scale seawater desalination devices is greatly extended.

In the field of biomedicine, the excellent biocompatibility of titanium alloys makes it the only choice for micro-valves of implantable medical devices, which are friendly to human tissues and avoid immune reactions. However, titanium alloy processing faces difficulties such as rapid wear of cutting tools due to cutting heat accumulation, large cold processing rebound affecting dimensional accuracy, and high-purity inert gas protection required for welding, which results in high manufacturing costs and limits the widespread popularization of civilian use.

 

 

① Engineering plastics: a pioneer in lightweighting

Polytetrafluoroethylene (PTFE) is unique with its ultra-low friction coefficient of nearly 0.04. As a valve sealing material, it ensures that the butterfly valves and ball valves in chemical pipelines switch smoothly without stagnation, and the seal is tight without leakage. It can withstand the erosion of almost all chemical reagents except for a few such as molten alkali metals. It is irreplaceable in the key position of valve sealing in pharmaceutical sterile workshops and chemical high-risk process pipelines;

Nylon (PA) has a significant leap in mechanical strength after being reinforced with glass fiber, taking into account self-lubrication and wear resistance. The small valves of automobile engine cooling circulation are made of nylon material, which achieves efficient heat dissipation control at a limited cost and helps vehicles to run energy-saving. However, its upper limit of heat resistance is limited to about 150°C, and its dimensional stability is poor under high temperature conditions, which affects long-term reliability.

Polyvinyl chloride (PVC) has good chemical stability, flame retardant properties and low cost. It is widely used in low-pressure valves for building water supply and drainage, and large-scale municipal water supply and drainage pipelines. However, it is not suitable for special working conditions due to its inability to resist organic solvent erosion and low-temperature brittleness.

 

② Ceramics: Super Hard Wear-Resistant Model

Alumina ceramics have excellent hardness, with a Mohs hardness of 9, second only to diamond. Under the conditions of high-velocity erosion of abrasive media and high-concentration particle wear of mine tailings, key components such as valve linings and valve cores are made of alumina ceramics, which have wear resistance far exceeding traditional metals, greatly extending the valve maintenance cycle.

 

Zirconium oxide ceramics have a breakthrough in toughness compared to traditional ceramics. Some stable zirconia ceramics have excellent thermal shock resistance. They are suitable for high-temperature continuous casting of steel metallurgy and high-temperature gas flow control valves in ceramic kilns. They can withstand frequent rapid cooling and heating shocks and maintain structural integrity and sealing performance. However, the inherent brittleness of ceramics has not been fundamentally solved. Complex shapes need to be finely carved with special grinding and high-temperature sintering processes, and the manufacturing efficiency and precision improvement face bottlenecks.

 

③ Composite materials: integrated advantage carriers

Fiber-reinforced composite materials such as carbon fiber reinforced epoxy resin, carbon fiber contributes high strength and high modulus properties, epoxy resin matrix is ​​cured and formed, and synergistically optimizes fatigue resistance and chemical resistance. Racing car high-performance brake system valves use such composite materials to achieve both lightweight and sensitive response under the stringent requirements of high-speed frequent braking.

Metal-based composite materials are typically aluminum-based silicon carbide. The dispersed silicon carbide ceramic particles strengthen the matrix hardness, and the toughness of metal aluminum ensures the reliability of the overall structure. Ultra-clean gas delivery valves are used in electronic chip manufacturing to strictly block the intrusion of dust particles and match the connection strength requirements of precision equipment. However, the interface microstructure of composite materials is complex, requiring fine control to ensure bonding strength, and the quality consistency control of the production process is difficult. Cost reduction depends on the deep integration and upgrading of industrial technology.

 

 

Looking to the future, valve material innovation will accelerate iteration with the help of multi-dimensional environmental perception. In the field of intelligent materials, shape memory alloys (such as nickel-titanium alloys) are expected to deeply empower valve components, enabling them to have environmental perception and adaptive adjustment capabilities, respond to subtle fluctuations in temperature and pressure in real time, automatically optimize flow control, reduce the manpower and time costs of industrial operation and maintenance, and move towards intelligent autonomous control.

Nanotechnology has deeply penetrated, the nanoscale optimizes the microstructure of materials, and nanoceramics and nanometal powders are formed through advanced sintering processes. It is expected to comprehensively improve the strength, toughness, and corrosion resistance of valve materials and unlock the high-efficiency potential contained in the microscopic world.

Under the general trend of environmental protection, the research and development of biodegradable materials focuses on short-term use of valve application scenarios. Disposable medical and biological experimental fluid valves are expected to achieve no residue degradation after use, reducing waste pollution from the source.

Additive manufacturing (3D printing) technology changes the valve design and manufacturing paradigm, breaks through the limitations of traditional processes, and integrates complex flow channels and special-shaped structure valves. The material utilization rate is greatly improved, the design iteration cycle is sharply reduced, and the personalized customization demands of niche and special working conditions are accurately met. Leading valve materials into a new era of efficiency, intelligence, and greenness, and continuously empowering the global fluid engineering system to move steadily towards refinement, stabilization, and sustainability.

From basic livelihood security to high-end technological frontiers, valve materials, with their constantly evolving performance and adaptability, firmly control every key node of fluids and continue to innovate and break through in the future. They will surely inject strong impetus into human technological progress and social development, and ensure the safe and efficient operation of fluid control systems under diverse and complex working conditions.