ASTM A249/A249M Grade N08800 Introduce
ASTM A249/A249M Grade N08800 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:1349°C - 1587°C
Application:Welded austenitic steel tubes for boilers, superheaters, heat exchangers and condensers
ASTM A249/A249M Grade N08800 Material Chemical Composition
The chemical composition of the ASTM A249/A249M Grade N08800 steel are as follows:
| Element | Min | Max |
|---|---|---|
| Carbon (C) | - | 0.1000 |
| Manganese (Mn) | - | 1.5000 |
| PhOsphorus (P) | - | 0.0450 |
| Sulfur (S) | - | 0.0150 |
| Silicon (Si) | - | 1.0000 |
| Nickel (Ni) | 30.0000 | 35.0000 |
| Chromium (Cr) | 19.0000 | 23.0000 |
| Copper (Cu) | - | 0.7500 |
| Titanium (Ti) | 0.1500 | 0.6000 |
| Aluminum (Al) | 0.1500 | 0.6000 |
| Iron (Fe) | 39.5000 | - |
ASTM A249/A249M Grade N08800 Material Mechanical Properties
Corrosion resistance is a measure of how resistant a material is to corrosion or rusting. ASTM A249/A249M Grade N08800 steel has excellent resistance to corrosion and can withstand exposure to most chemicals, such as acids, alkalis, and other corrosive substances.
The mechanical properties of the ASTM A249/A249M Grade N08800 steel are as follows:
| YieldRp0.2 | ≤ 297 (MPa) |
| TeileRm | ≤ 685 (MPa) |
| ImpactKV/Ku | 24(J) |
| ElongationA | 31% |
| Reduction in cross section on fractureZ | 22% |
| As-Heat-Treated Condition | Solution and Aging, Annealing, Ausaging, Q+T,etc |
| Brinell hardness (HBW) | 341 |
ASTM A249/A249M Grade N08800 Material Thermal Properties
The thermal performance parameters of the ASTM A249/A249M Grade N08800 steel are as follows:
| Temperature (°C) | 22 | 928 | 266 |
| Modulus of elasticity (GPa) | - | 194 | - |
| Mean coefficient of thermal expaion ×10-6/(°C) | - | - | 43 |
| Thermal conductivity (W/m·°C) | - | 43.3 | 31.2 |
| Specific thermal capacity (J/kg·°C) | - | 444 | - |
| Specific electrical resistivity (Ω mm²/m) | 0.44 | - | - |
| Deity (kg/dm³) | - | - | 321 |
| Poisson’s coefficient, ν | - | - | 343 |
ASTM A249/A249M Grade N08800 Material Machining Technology
When it comes to machining ASTM A249/A249M Grade N08800 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 Grade N08800 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.