In industrial fluid control systems, the selection of valve materials directly determines the service life, operational stability and safety factor of equipment, and is a key link balancing performance and cost. The core principle of material selection is to precisely match materials with medium characteristics and working condition parameters, avoiding failures caused by corrosion, wear, high temperature and high pressure and other factors.
Valve material selection should start from two core dimensions: body material and trim material. The body material mainly bears medium pressure and environmental impacts, and common types are divided into metal materials and non-metal materials. Among metal materials, cast iron is low-cost and has good casting performance. It is suitable for low-pressure working conditions with weakly corrosive media such as water and air, and is a common choice for water supply and drainage and HVAC systems. Cast steel has better mechanical strength and temperature resistance than cast iron, can handle medium and high-pressure steam, oil and other media, and is widely used in conventional working conditions of petrochemical and power industries. Stainless steel (such as 304, 316) has excellent corrosion resistance, making it the first choice for corrosive media such as acid-base solutions and seawater. 316 stainless steel has stronger pitting corrosion resistance due to the addition of molybdenum, suitable for high-corrosion environments such as coastal areas and chemical plants. Special alloy materials (such as Hastelloy, Monel alloy) are used for extreme working conditions with strong corrosion, high temperature and high pressure, such as strong acid and high-temperature molten salt, but the cost is high and should be selected as needed. Non-metallic materials such as plastics and ceramics: plastic valves (PVC, PP) have strong corrosion resistance and light weight, suitable for low-pressure corrosive media in civil or light industry scenarios, while ceramic valves have excellent wear resistance and can be used for abrasive media containing solid particles.
Valve trim materials are in direct contact with the medium, determining sealing performance and wear resistance, and need to be focused on according to the wear and corrosion of the medium. Common sealing surface materials include copper alloys, suitable for low-pressure and low-temperature water and steam media; stainless steel alloy sealing surfaces have high hardness and good corrosion resistance, suitable for medium and high-pressure corrosive media; cemented carbide (such as surfacing Stellite alloy) has extremely high hardness, outstanding wear and erosion resistance, suitable for media containing particles or high pressure difference working conditions. Valve stem materials need to balance strength and corrosion resistance: carbon steel quenched and tempered can be used for conventional working conditions, and stainless steel is preferred for corrosive working conditions.
In addition to medium characteristics, working condition parameters are also important basis for material selection. Under high-temperature working conditions, the thermal stability and oxidation resistance of materials need to be considered. For example, chrome-molybdenum steel is preferred for high-temperature steam systems; for low-temperature working conditions, the low-temperature toughness of materials should be paid attention to avoid low-temperature brittle fracture, and low-temperature steel is commonly used. High-pressure working conditions have strict requirements on the mechanical strength of materials, and high-strength cast steel or forged steel should be selected. In addition, solid particles in the medium will aggravate the wear of valve trim, so wear-resistant materials or protective coatings should be selected.
In the actual selection process, it is also necessary to balance cost and performance. Cost-effective cast iron and cast steel should be preferred for conventional working conditions; stainless steel and special alloy materials should be selected for corrosive or extreme working conditions to avoid frequent maintenance caused by improper material selection, which will increase the comprehensive cost. At the same time, relevant industry standards should be followed, combined with the design requirements of specific working conditions to ensure compliance of selection.
In conclusion, valve material selection is a systematic decision-making process, which needs to comprehensively consider three elements: medium characteristics, working condition parameters and cost budget, and accurately match material performance with actual needs to ensure the long-term stable operation of valves.
Product Parameters
| Material Category | Specific Material | Applicable Medium | Applicable Working Conditions | Cost Level | Core Advantages | Notes | ||||||||||||
| Metal Body Materials | Cast Iron | Water, air, neutral liquids | Low pressure (≤1.6MPa), normal temperature | Low | Low cost, excellent casting performance | Non-corrosion-resistant, non-high-temperature-resistant; avoid use with acid-base media | ||||||||||||
| Cast Steel (WCB) | Steam, oil products, natural gas | Medium and high pressure (≤10MPa), medium temperature (≤425℃) | Low-Medium | High mechanical strength, better temperature resistance than cast iron | Weak corrosion resistance; not suitable for strongly corrosive media | |||||||||||||
| 304 Stainless Steel | Weak acid/alkali solutions, fresh water, food-grade media | Medium and low pressure, normal to medium temperature | Medium | Good corrosion resistance, compatible with hygienic applications | Not resistant to chloride ion corrosion; avoid use with seawater | |||||||||||||
| 316 Stainless Steel | Seawater, chloride-containing solutions, moderately corrosive acids and alkalis | Medium and high pressure, medium temperature | Medium-High | Strong pitting corrosion resistance, better corrosion resistance than 304 | Higher cost than 304; not recommended for regular non-corrosive working conditions | |||||||||||||
| Hastelloy | Strong acids (hydrochloric acid, sulfuric acid), strong oxidants | Extreme working conditions with high temperature, high pressure and strong corrosion | High | Excellent resistance to strong corrosion | Expensive; only suitable for special harsh working conditions | |||||||||||||
| Non-Metal Body Materials | PVC/PP Plastic | Acid-base solutions, low-concentration chemical additives | Low pressure (≤1.0MPa), normal temperature | Low | Lightweight, strong corrosion resistance, easy installation | Non-high-temperature-resistant, low mechanical strength; not suitable for high-pressure working conditions | ||||||||||||
| Ceramic | Slurry containing solid particles, abrasive media | Low to medium pressure, normal temperature | Medium | Extremely high wear resistance and corrosion resistance | High brittleness, weak impact resistance; avoid severe vibration | |||||||||||||
| Trim Sealing Surface Materials | Copper Alloy | Water, low-pressure steam | Low pressure, low temperature (≤200℃) | Low | Good sealing performance, easy processing | Non-corrosion-resistant, non-high-temperature and high-pressure-resistant | ||||||||||||
| Stainless Steel Alloy | Moderately corrosive media, oil products | Medium and high pressure, medium temperature | Medium | High hardness, corrosion resistance, wide applicability | Not suitable for abrasive working conditions with hard particles | |||||||||||||
| Stellite Alloy (Overlay Welding) | Slurry containing particles, high pressure difference media | High temperature, high pressure and high wear working conditions | Medium-High | Outstanding wear and erosion resistance | High processing cost; requires professional overlay welding technology | |||||||||||||
| Cemented Carbide | Highly abrasive mineral slurry, coal powder | Extreme wear working conditions | High | Extremely high hardness, long service life | Relatively high brittleness; avoid dry running conditions | |||||||||||||
| Valve Stem Materials | Quenched and Tempered Carbon Steel | Non-corrosive media, oil products | Regular low-pressure and medium-temperature working conditions | Low | Mechanical strength meets basic requirements, low cost | Prone to rust; not suitable for humid or corrosive environments | ||||||||||||
| 2Cr13 Stainless Steel | Slightly corrosive media, water vapor | Medium-pressure and medium-temperature working conditions | Medium | Good corrosion resistance, high strength | Regular maintenance for rust prevention required | |||||||||||||
| 316 Stainless Steel | Strongly corrosive media, seawater | Corrosive working conditions | Medium-High | Excellent corrosion resistance and pitting resistance | Higher cost than carbon steel; unnecessary for regular working conditions | |||||||||||||
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