Heater Seamless Steel Tube

Seamless steel pipes for heaters are specially designed for high-temperature, high-pressure, and heat exchange applications. They are primarily used in boilers, economizers, superheaters, feedwater heaters, and heat exchangers, requiring high-temperature resistance, creep resistance, stable pressure performance, and leak-proof properties.

I. Core Definitions and Applications

• Definition: Weldless, integral rolled or cold-drawn carbon steel or alloy steel pipe, used for heating surfaces and pressure pipelines in heating or heat exchange equipment.
• Typical scenarios:
  • Boiler: Water wall, superheater, reheater, economizer
  • Industry: Water heaters, heat exchangers, steam pipelines
  • Power: Thermal power / Nuclear power, Petrochemical heating furnace, Waste heat recovery

2. Mainstream Standards and Materials (Most Commonly Used)

1. China standards (GB)

table

2. International Standards (ASTM/ASME)

table

3. Quick Reference of Common Materials

• Carbon steel: 20#/20G,1020 (AISI), C22 (DIN) —suitable for medium-temperature and medium-pressure applications, offering excellent cost-performance ratio
• Low alloy: 15CrMoG, 12Cr1MoVG, T22-High temperature resistance, creep resistance, and high service strength
• High alloy/heat-resistant: T91, T92, TP304H-used in supercritical/ultra-supercritical units (≤650°C)

III. Manufacturing Process

• Hot-rolled seamless (HRS): tube billet heating →piercing→continuous rolling →sizing→heat treatment-large diameter, thick wall, low cost
• Cold drawing/rolling (CDW): Pickling →Phosphating→Cold deformation →Normalizing/Tempering-High precision, thin-walled, smooth surface, dimensional stability (commonly used in water heaters)
• Critical controls: grain size ≥8, low sulfur phosphorus (≤0.01%), 100% non-destructive testing (UT/ET), hydrostatic test (1.5 times design pressure)

IV. Core Performance Requirements

• Mechanical properties: Tensile strength 415–700 MPa, Yield strength 245–450 MPa, Elongation ≥18% (depending on material/standard)
• Thermal strength: High-temperature creep resistance (core performance indicator of alloy pipes)
• Dimensions: Outer diameter ±0.75%–1.0%, Wall thickness ±5%–10%, Ellipticity ≤0.6%
• Inspection: Root-by-root hydrostatic testing, expansion/flattening, ultrasonic/wedding stream testing, metallographic examination

V. Key Points in Model Selection

1. material selection according to working condition
   • Medium temperature (≤450°C), medium pressure: 20#/20G, A192
   • High temperature (450–600°C), high pressure: 15CrMoG, T22
   • Ultra-high temperature (≥600°C): T91, T92, TP304H
2. Select type by device
   • Boiler heating surfaces: A210, A213, GB 5310
   • Water heater: A556, GB/T 24591 (U-shaped/snake-shaped tube, bending radius ≥1.5D)
   • Heat exchanger / economizer: A192,20#
3. Process selection
   • High Precision / Thin Wall: Cold Drawing (CDW)
   • Large diameter / Thick wall: Hot rolled (HRS)