What Are the Different Types of Boiler Tubes?
2026/02/10
What Are the Different Types of Boiler Tubes?
Many steel pipes are used in boiler systems, but each pipe has a different position and function. We need to select suitable boiler tubes based on actual operating conditions. This involves many factors, such as pipe type, material, and manufacturing process, making the selection of appropriate boiler tubes a crucial issue.
Boiler Tube Comparison Chart
| Type | Where is it used? | Effect | Recommended materials | Common standards |
|---|---|---|---|---|
| Fire-tube / smoke tubes | Inside the shell (hot gas inside tubes, water outside) | Produces steam/hot water in many packaged boilers | Carbon steel | (Depends on boiler design; “fire-tube vs water-tube” is the key classification) |
| Waterwall / evaporator tubes | Furnace walls (water/steam inside tubes) | Absorbs radiant heat; makes steam/water mixture | Carbon/low-alloy depending on heat & corrosion |
Seamless carbon / low-alloy often specified in power/industrial water-tube designs |
| Generating bank tubes | Convection pass (tube bank after furnace) | Continues boiling/heat transfer | Carbon steel | (Selected by design code/OEM; often similar families as evaporator tubes) |
| Superheater tubes | After evaporation (high-temp zones) | Raises steam temperature above saturation | More alloy as temperature rises; austenitic at hottest zones | ASTM A213 / ASME SA213 (alloy & stainless boiler/superheater tubes) |
| Reheater tubes | Between turbine stages (utility plants) | Reheats partially expanded steam | Similar logic to superheater | Often A213/SA213 grades in high-temp sections |
| Economizer tubes | Flue gas outlet area (cooler end) | Preheats feedwater using waste heat | Carbon/low-alloy; corrosion risk can drive upgrades | Commonly carbon steel tube specs; function is efficiency-focused |
Boiler tubing is not a single product but rather composed of multiple components, and different components utilize different types of boiler tubing. If "the same grade of boiler tubing were used everywhere," the tubing would be excessively expensive for use in cold regions, but would be of insufficient quality and provide inadequate protection in high-temperature/corrosive areas.
Which tube material grade should I use—carbon, alloy, or stainless?
This is a frequently asked question. To put it simply, we can understand it as: in which applications do we use which types of boiler tubes?
- Carbon steel boiler Tube is often used in cooler sections where metal temperature and corrosion risk are manageable.
- Low-alloy Cr-Mo steel Tube are often used as temperatures climb (common in hotter pressure parts).
- Austenitic stainless / high-alloy are often selected for the hottest superheater/reheater conditions.
These steel pipes also have their corresponding standards.
| Application / Tube Type | Most Common (ASTM / ASME) | Europe (EN) | China (GB/T) | Japan (JIS) |
|---|---|---|---|---|
| Seamless Carbon Steel Boiler & Superheater Tubes (typical for low–mid temp sections) | ASTM A192 / ASME SA-192; ASTM A210 / ASME SA-210 | EN 10216-2 | GB/T 3087 (low & medium pressure); GB/T 5310 (high pressure) |
JIS G 3461 |
| ERW (Welded) Carbon Steel Boiler & Superheater Tubes (when welded tube is permitted) | ASTM A178 / ASME SA-178 | EN 10217-2 | GB/T 28413 (welded carbon steel tubes for boilers & heat exchangers) | JIS G 3461 (includes seamless + ERW in many procurement practices) |
| Seamless Low-Alloy Steel Boiler & Superheater Tubes (higher-temp areas; creep-resistant alloys) | ASTM A209 / ASME SA-209 (C-Mo); ASTM A213 / ASME SA-213 (alloy & stainless for boiler/superheater/heat exchanger) | EN 10216-2 | GB/T 5310 (commonly used for high-temp/pressure boiler tubing in China) | JIS G 3462 |
| Seamless Stainless Steel Boiler / Superheater / Heat Exchanger Tubes | ASTM A213 / ASME SA-213 | EN 10216-5 | GB/T 13296 | JIS G 3463 |
| Welded Stainless Steel Boiler / Superheater / Heat Exchanger / Condenser Tubes | ASTM A249 / ASME SA-249 | EN 10217-7 | GB/T 24593 (welded austenitic stainless steel tubes for boiler & heat exchanger) | (Often specified by project spec / buyer standard; stainless boiler tubing is commonly handled under JIS G 3463 procurement logic depending on scope) |
Seamless vs welded (ERW)—which should I specify for boiler tubes?
- Seamless boiler tubes are typically used in high-pressure, high-temperature environments and require heat circulation; they are sometimes highlighted in design drawings.
- In less demanding environments, we recommend ERW steel pipes because of their relatively lower cost. Of course, we will provide a complete quality assurance plan (including reports on non-destructive testing, water pressure/voltage testing, etc.).
How do we prevent boiler tube failures (and stop repeat leaks)
1. Control waterside chemistry to prevent scaling/corrosion
Waterside failures are frequently linked to scaling, corrosion, and chemical imbalance, which can drive localized overheating.
Actions that work:
Tighten feedwater/boiler-water control (TDS, oxygen control where applicable, consistent treatment program).
Track deposit indicators and clean proactively.
2. Manage fireside deposits/erosion/corrosion
Fuel ash, soot, and temperature gradients can damage external tube surfaces over time.
Actions that work:
Tune combustion, improve sootblowing strategy, monitor slagging/fouling patterns.
Consider tube material upgrades/coatings in known high-risk zones (guided by failure history, not guesswork).
3. Institutionalize inspection + root cause learning
EPRI and other industry guidance emphasizes formal programs that combine inspection, failure mechanism identification, and corrective actions to reduce repeat events.
Actions that work:
Baseline thickness measurements, targeted NDT in hot spots.
Keep a tube-failure “map” by location/type; treat repeats as a system problem, not a one-off repair.
Any more questions?
If you need information about your boiler type, tube location (economizer/superheater/water wall, etc.), and design temperature/pressure + fuel + water chemistry, TORICH can help you match appropriate tube standards and materials, prepare clear procurement specifications, and reduce the risk of recurring tube failures—allowing you to buy once, install once, and operate for a longer period.
