High Pressure Boiler Tubes: Material Selection and Heat-Resistant Design

Boiler tube failure is rarely sudden — it is the end of creep, scaling and thermal fatigue acting for years. Selecting high pressure boiler tubes correctly is therefore a design decision about decades, not a purchase-order line about price.

What Boiler Tube Must Survive

• Internal pressure at elevated temperature, which drives creep

• Steam-side oxidation and scale formation that raises metal temperature

• Fireside corrosion and ash erosion in coal and biomass units

• Thermal fatigue from start-up, load changes and soot blowing

• Water-side corrosion and under-deposit attack in evaporator circuits

Grade Selection by Temperature

Standards That Govern Supply

• GB/T 5310 — seamless steel tubes for high-pressure boilers (China)

• GB/T 3087 — seamless tubes for low and medium pressure boilers

• ASME SA-210 / SA-213 / SA-335 and DIN 17175 for export and EPC projects

• Delivery with normalising and tempering, plus full mechanical and metallographic records

Design Rules That Prevent Failure

• Keep measured metal temperature below the design assumption — scale is an insulator

• Avoid abrupt wall-thickness changes and rigid restraints that concentrate thermal stress

• Specify bends with controlled ovality and minimum wall thinning

• Require 90% NDT plus hydrostatic testing before shipment

• Plan inspection intervals for wall thickness, oxide scale and microstructure

Frequently Asked Questions

Which is better, 20G or 15CrMoG?

20G is a carbon manganese boiler steel for lower temperatures and lower cost. 15CrMoG is required once creep strength above roughly 450 °C governs the design.

Do boiler tubes need heat treatment after bending?

Small cold bends may not; hot-formed or heavily cold-worked bends usually require re-normalising and tempering to restore properties.

How long should boiler tube last?

With correct grade, water chemistry and temperature control, 20–30 years is common; most early failures trace back to overheating or poor water treatment.

Conclusion

High pressure boiler tubing is a system decision: grade, wall thickness, temperature control and water chemistry all interact. Zhantong supplies 20G, 15CrMoG, 12Cr1MoVG and high-alloy boiler tube to GB/T 5310, ASME and DIN requirements with complete traceability. Send a datasheet and we will match the grade.