ASTM A249/A249M Type 309HCb Introduce
ASTM A249/A249M Type 309HCb is an austenitic stainless steel specifically designed for use in boiler, superheater and heat exchanger tubes, which contain higher amounts of chromium and nickel compared to other stainless steels. This grade of steel is popular for its ability to resist corrosion and oxidation, and for its high strength-to-weight ratio. Due to its outstanding properties, it is ideal for a range of applications, such as pressure vessels, heat exchangers, and condensers.
Smelting temperature:1515°C - 1895°C
Application:Welded austenitic steel tubes for boilers, superheaters, heat exchangers and condensers
ASTM A249/A249M Type 309HCb Material Mechanical Properties
This ASTM A249/A249M covers ferritic/austenitic stainless steel welded and heavily cold worked tubes for general corrosive service, heat exchangers, condensers, heat treatment special and other similar applications. ASTM A249/A249M Type 309HCb is typically used within a range of temperatures of −450°F (−268°C) and higher.
The mechanical properties of the ASTM A249/A249M Type 309HCb steel are as follows:
| YieldRp0.2 | ≤ 985 (MPa) |
| TeileRm | ≤ 215 (MPa) |
| ImpactKV/Ku | 42(J) |
| ElongationA | 31% |
| Reduction in cross section on fractureZ | 41% |
| As-Heat-Treated Condition | Solution and Aging, Annealing, Ausaging, Q+T,etc |
| Brinell hardness (HBW) | 443 |
ASTM A249/A249M Type 309HCb Material Thermal Properties
The thermal performance parameters of the ASTM A249/A249M Type 309HCb steel are as follows:
| Temperature (°C) | 13 | 259 | 981 |
| Modulus of elasticity (GPa) | - | 931 | - |
| Mean coefficient of thermal expaion ×10-6/(°C) | - | - | 23 |
| Thermal conductivity (W/m·°C) | - | 11.3 | 24.2 |
| Specific thermal capacity (J/kg·°C) | - | 433 | - |
| Specific electrical resistivity (Ω mm²/m) | 0.33 | - | - |
| Deity (kg/dm³) | - | - | 223 |
| Poisson’s coefficient, ν | - | - | 414 |
ASTM A249/A249M Type 309HCb Material Machining Technology
Machinability is a measure of how easily a material can be cut, drilled, or finished using machine tools. ASTM A249/A249M Type 309HCb steel has a high machinability rating and can be easily cut, drilled, or finished using machine tools.