Valve material selection guide for high temperature conditions
When selecting valve materials for high temperature conditions, factors such as temperature range, medium characteristics, and pressure need to be considered to ensure safe and reliable operation of the valve.
1. Temperature range
(1) Below 425℃
Carbon steel: has good strength and cost-effectiveness, suitable for general steam and oil media.
(2) 425℃ - 600℃
Low alloy steel (such as 1.25Cr-0.5Mo, 2.25Cr-1Mo): contains elements such as chromium and molybdenum, improves high temperature strength and creep resistance, and is suitable for high temperature and high pressure pipelines in the petrochemical industry.
Chromium-molybdenum steel (such as ZG1Cr5Mo): suitable for water, steam, hydrogen and sulfur-containing oil products, with a maximum temperature of 550℃-600℃.
(3) Above 600℃
High temperature alloy (such as Inconel 600, Inconel 625): nickel-based alloy with excellent high temperature strength and oxidation resistance, suitable for extreme high temperature environments, such as aerospace engines.
Stainless steel (such as 310S, 316H): Some models can operate at temperatures up to 800°C and are suitable for high-temperature corrosive media.
2. Medium characteristics
(1) Corrosive media
Stainless steel (such as 304, 316, 316L): Suitable for corrosive media such as acids, alkalis, and salts. 316L has better tolerance to chloride ions.
Nickel-based alloys (such as Hastelloy): Suitable for more demanding chemical media and have excellent corrosion resistance.
(2) Sulfur-containing media
Chromium-molybdenum steel (such as ZG1Cr5Mo): Suitable for sulfur-containing oils, but pay attention to temperature limits.
3. Pressure
High-pressure conditions
High-strength alloy steel: For example, the use of self-tightening seals and wedge-shaped valve disc structures can improve the strength and sealing performance of the valve.
High-temperature alloys: With high strength and oxidation resistance, suitable for high temperature and high pressure environments.
4. Other factors
Thermal expansion: Consider the thermal expansion coefficient of the material to avoid sealing failure or structural damage caused by thermal expansion and contraction.
Wear: For working conditions with wear, choose wear-resistant materials or adopt surface hardening treatment.
Cost and maintenance: Comprehensively consider the cost, processing difficulty and maintenance convenience of the material.
When selecting valve materials under high temperature conditions, factors such as temperature, medium, and pressure should be comprehensively considered. Materials with good high temperature strength, oxidation resistance and corrosion resistance should be selected to ensure the safe and reliable operation of the valve in high temperature environments.