Steel Pipe Material Selection for Thermal Industry

 Steel pipes used in thermal power plants, boilers, heat exchangers, steam pipelines, and industrial heating systems must withstand high temperatures, high pressures, thermal stress, and corrosive operating environments. Choosing the correct steel pipe material helps improve operational safety, thermal efficiency, equipment reliability, and service life while reducing maintenance and downtime costs.

 

Core Selection Principles

Material selection for thermal industry steel pipes follows 5 key criteria:

  1. Temperature & pressure rating (primary factor)
  2. High-temperature creep strength & structural stability
  3. Oxidation, steam & flue gas corrosion resistance
  4. Weldability, processing performance & dimensional precision
  5. Cost economy and standard compliance (ASME ASTM, GB, EN)

 

Classification by Service Temperature & Recommended Materials

Thermal industry piping materials span a spectrum from economical carbon steels to high-performance alloys. Understanding the capabilities and limitations of each class is essential.

 

Low Temperature & Low/Medium Pressure (≤450℃)

Common standards and material: ASTM A106 Grade B, ASTM A53, ASTM A179, GB/T 5310 (20G)

Advantages: cost-effective, good mechanical strength, easy fabrication

Limitations: limited high-temperature resistance, lower oxidation resistance

Typical applications: water pipelines, low-pressure steam systems, utility piping

 

Medium Temperature & High Pressure (450–550℃)

Common standards and material: DIN 17175 (13CrMo44, 10CrMo910), GB/T 5310 (15CrMoG, 12Cr1MoVG)

Advantages: excellent high-temperature endurance, anti-oxidation, suitable for long-term high-pressure thermal operation

Limitations: limited ultra-high temperature (>550–600°c) service, requires strict welding control and heat treatment (PWHT), lower creep strength than advanced alloy steels (e.g., P91), performance depends heavily on manufacturing quality

Typical applications: subcritical boiler water wall, economizer, medium-pressure superheater, industrial furnace pipeline

 

High Temperature & Ultra-High Pressure (550–620℃)

Common standards and material: ASTM A335 (P11, P22, P5, P9, P91), ASTM A213 (TT91)

Advantages: superior creep strength, long service life under 600–620℃ ultra-supercritical parameters, the mainstream material for modern high-efficiency thermal power units

Limitations: higher material and manufacturing cost compared to carbon steel, strict heat treatment requirements, welding complexity increases with higher alloy grades (especially p91), sensitive to improper fabrication processes, requires strict quality control and NDT

Typical applications: ultra-supercritical power plant main steam pipe, reheat pipe, superheater header, high-temperature boiler heating surface

 

Ultra-High Temperature (620–680℃)

Common standards and material: ASTM A312 / ASTM A213 (Super304H, TP347H, HR3C, 310S)

Advantages: Outstanding high-temperature corrosion and oxidation resistance, stable microstructure at ultra-high temperature

Limitations: very high material cost compared to conventional alloy steels, difficult machining and welding, requires strict fabrication and heat treatment control, lower mechanical strength compared to martensitic steels at high pressure

Typical applications: final stage superheater/reheater, waste-to-energy boiler, high-corrosion flue gas environment

 

Corrosive & Special Thermal Environment

Common standards and material: ASTM A789 / A790 (2205, 2507), ASTM B407 (Incoloy 800H), ASTM B167 (Alloy 690), ASTM A297 (HP40Nb)

Advantages: resist sulfur corrosion, chloride corrosion, hydrogen embrittlement; for harsh thermal working conditions

Limitations: very high material cost and limited availability, complex welding and strict fabrication requirements

requires specialized heat treatment and process control, more difficult machining compared with conventional steels, higher inspection and quality control requirements (PMI, NDT)

Typical applications: biomass power, waste incineration, petrochemical heating furnace, hydrogen production thermal system, nuclear power

 

Cryogenic Thermal System (≤ -40℃)

Common standards and material: GB/T 18984 (16MnDG), ASTM A333 / A334 (Gr. 6, 8)

Advantages: Low-temperature impact toughness, no brittle fracture at ultra-low temperature

Limitations: strict impact toughness (Charpy v-notch) requirements, higher cost for alloy and stainless steel grades, requires careful material selection and heat treatment control, limited applicability for high-temperature service systems

Typical applications: cold energy storage, low-temperature thermal cycle, LNG associated thermal pipeline

 

Conclusion

Steel pipe material selection is essential for the safety, efficiency, and durability of thermal industry systems. By carefully evaluating operating temperature, pressure, corrosion conditions, and mechanical requirements, engineers can select the most appropriate steel pipe materials for reliable long-term operation in modern thermal industry applications.

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