What is the Maximum Operating Temperature of Alloy Steel SMLS Pipes?

In daily life, many scenes are inseparable from high temperature resistant materials. For example, the boiler at home will generate a high temperature and high pressure environment inside when it is running; there are also various pipelines in the chemical industry that transport high temperature and corrosive media. In these scenes with extremely high requirements for the heat resistance of materials, alloy steel smls steel pipes play a key role. With its excellent high temperature resistance, it provides a guarantee for the safe and stable operation of the equipment. But do you know what its maximum operating temperature is? The following key factors need to be considered:
 
1. Influence of alloy composition
 
Different alloying elements have different effects on the heat resistance of steel. Commonly used alloying elements to improve the heat resistance of steel include chromium (Cr), molybdenum (Mo), vanadium (V), tungsten (W), etc.
Chromium (Cr): It is the main element that improves the oxidation resistance and corrosion resistance of steel. Stainless steel with a high chromium content has excellent high temperature resistance.
Molybdenum (Mo): It can significantly improve the high temperature strength, creep resistance and heat resistance of steel.
Therefore, the maximum operating temperature of steel pipes with different alloy compositions will vary greatly. For example, the maximum operating temperature of low-alloy structural steel with a low chromium content may be only a few hundred degrees; while high-alloy heat-resistant steel or stainless steel can be used at higher temperatures.
 
2. Influence of the use environment
 
Medium: Different media have different corrosive properties to steel pipes. Corrosion will be more serious at high temperatures. For example, in a high-temperature sulfur-containing environment, the corrosion resistance of steel pipes will drop significantly.
Pressure: Under high temperature and high pressure environment, the creep rate of steel pipes will accelerate, resulting in a decrease in strength. Therefore, when selecting steel pipes, the effects of temperature and pressure need to be comprehensively considered.
 
3. Impact of application areas
 
Different application areas have different temperature requirements for steel pipes.
Boiler pipes: High-pressure boiler pipes need to operate for a long time under high temperature and high pressure conditions, and their maximum operating temperature is usually between 500-650℃, or even higher. For example, the maximum wall temperature of high-pressure boiler pipes reaches 600-630℃. High-pressure boiler seamless steel pipes (GB5310-2008) are suitable for manufacturing steam boilers with high pressure and above, and have a high operating temperature.
Pipes for petrochemical industry: Petrochemical cracking furnace tubes need to withstand the corrosion and erosion of the medium at high temperature, and their maximum operating temperature is usually between 600-800℃.
Aerospace pipes: Special alloy steel pipes used in the aerospace field need to work at higher temperatures.
 
4. Common alloy steels and their maximum operating temperature range (for reference only)
 
The following are some common alloy steel seamless pipes and their approximate maximum service temperature ranges, but please note that this is only a rough estimate and the actual service temperature needs to be calculated and verified according to specific working conditions:
Low alloy structural steel (such as 16Mn, Q345R, etc.): The maximum operating temperature is generally around 400-500℃.
Alloy structural steel (such as 15CrMoG, 12Cr1MoVG, etc.): The maximum operating temperature is generally around 500-600℃.
Heat-resistant steel (such as Cr5Mo, 1Cr18Ni9Ti, etc.): The maximum operating temperature is generally around 600-800℃.
Stainless steel (such as 304, 316L, etc.): The maximum operating temperature depends on the specific steel type and the use environment, generally around 600-900℃, but care should be taken to avoid long-term use in the range of 450-860℃ to prevent intergranular corrosion.
 
5. How to determine the maximum operating temperature
Check relevant standards: Find relevant national standards, industry standards or international standards, such as GB/T 1220 "Stainless Steel Bars", ASTM A213 "Standard Specification for Seamless Ferritic and Austenitic Alloy Steel Boiler, Superheater and Heat Exchanger Tubes", etc.
Conduct material tests: Conduct high temperature tensile tests, creep tests, endurance strength tests, etc. to evaluate the mechanical properties of steel pipes at high temperatures.
Consult professionals: Consult material experts or steel pipe manufacturers for more professional advice.