ASTM A249/A249M Type 309S Introduce
ASTM A249/A249M Type 309S 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:1191°C - 1973°C
Application:Welded austenitic steel tubes for boilers, superheaters, heat exchangers and condensers
ASTM A249/A249M Type 309S Material Mechanical Properties
Tensile strength is a measure of the amount of force that can be applied to a material before it is stretched beyond its yield strength. The tensile strength of ASTM A249/A249M Type 309S steel can range from 310 MPa to 620 MPa, depending on the grade of steel used and the desired characteristics. The higher the tensile strength, the higher the steel's resistance to deformation and breaking.
The mechanical properties of the ASTM A249/A249M Type 309S steel are as follows:
YieldRp0.2 | ≤ 517 (MPa) |
TeileRm | ≤ 578 (MPa) |
ImpactKV/Ku | 43(J) |
ElongationA | 21% |
Reduction in cross section on fractureZ | 43% |
As-Heat-Treated Condition | Solution and Aging, Annealing, Ausaging, Q+T,etc |
Brinell hardness (HBW) | 441 |
ASTM A249/A249M Type 309S Material Thermal Properties
The thermal performance parameters of the ASTM A249/A249M Type 309S steel are as follows:
Temperature (°C) | 31 | 192 | 711 |
Modulus of elasticity (GPa) | - | 858 | - |
Mean coefficient of thermal expaion ×10-6/(°C) | - | - | 21 |
Thermal conductivity (W/m·°C) | - | 32.3 | 34.2 |
Specific thermal capacity (J/kg·°C) | - | 441 | - |
Specific electrical resistivity (Ω mm²/m) | 0.34 | - | - |
Deity (kg/dm³) | - | - | 244 |
Poisson’s coefficient, ν | - | - | 143 |
ASTM A249/A249M Type 309S Material Machining Technology
When it comes to machining ASTM A249/A249M Type 309S steel, there are several guidelines that should be followed to ensure optimal results. First and foremost, the cutting tool material should be of a high grade. ASTM A249/A249M Type 309S steel is extremely hard and can cause excessive wear and tear on lower-grade cutting tools. Second, the cutting speed should be carefully chosen. High cutting speeds can be used to reduce forces during machining; however, they can also reduce tool life. Therefore, it is essential to find the correct balance between cutting speed and tool life. Third, heavy-duty cutting fluids should be used during the machining process to ensure optimal results. The fluids should be capable of lubricating the material and preventing build-up of heat, which can cause the tool to lose its edge quickly.