Application of Mild Steel Pipes in Boilers

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Mild steel tube is carbon steel pipe with a carbon content of less than 0.25%. The application of mild steel pipes in boilers is mainly reflected in their excellent physical and chemical properties, which make mild steel pipes widely used in boiler manufacturing. Mild steel pipes are usually used to manufacture various low-pressure boilers, superheated steam pipes, boiling water pipes, water-cooled wall pipes and locomotive boiler tube.

Application advantages

1. Mild steel pipes have good plasticity and high toughness

Mild steel pipes are made of soft steel and have good plasticity and toughness. They can be continuously deformed under high temperature and high pressure. They are not prone to rupture and deformation during boiler operation, and can resist fatigue damage caused by cyclic stress to ensure the safe operation of the boiler.

2. Mild steel pipes have low thermal expansion and high strength

Mild steel pipes have a small thermal expansion coefficient and can expand and contract slowly when the temperature changes, avoiding stress concentration and evaluation deformation caused by thermal expansion and contraction, thereby extending the service life of the boiler. In addition, mild steel pipes have high strength and can withstand large tensile and compressive forces under high temperature and high pressure, ensuring the strength and stability of the boiler.

3. Good corrosion resistance of mild steel pipes

The chemical composition of mild steel pipes is stable and not easily affected by corrosion and oxidation. Even in high temperature and high pressure environments, there will be no corrosion or ablation, ensuring the safety and stability of boiler operation.

Specific application examples

‌SA-210C (20, 20G): This mild steel is suitable for heating surface pipes of low and medium pressure boilers (working pressure is generally not more than 5.88MPa, working temperature is below 450℃).

‌15CrMo (T11, T12, P11, P12): This mild steel improves the stability of carbides due to the addition of chromium, and is suitable for high temperature working environments, but long-term use above 550℃ will lead to a decrease in thermal strength.

‌12Cr1MoV (T22, P22): This mild steel forms a dense oxide protective film on the surface at 580℃, has good oxidation resistance and weldability, and is suitable for high temperature working environment.

‌T23: This mild steel has a strength 93% higher than T22 at 600℃, and has better weldability and processability, and is suitable for high temperature working environment.

‌T91: This improved 9Cr-1Mo type high-strength martensitic heat-resistant steel has high impact toughness, thermal strength and corrosion resistance, and is suitable for headers and steam pipes in subcritical and supercritical boilers.

Summary

In summary, mild steel pipes have the advantages of good plasticity, high toughness, low thermal expansion, high strength, and corrosion resistance in boiler applications. They can meet the use requirements of boilers under high temperature and high pressure and ensure the safe operation of boilers.