ASTM A240/A240M 309HNb Introduce
ASTM A240/A240M 309HNb is an international standard that specifies requirements for chromium and chromium-nickel stainless steel plate, sheet, and strip for pressure vessels and for general applications. It applies to the following grades: type 304, 304L, 316, 316L, 321, and 347, for rolled and forged products; and type 304H, 347H, 17-4PH, 630, and 631/N08367, for hot- and cold-rolled sheet and strip.
Smelting temperature:1422°C - 1155°C
Application:Heat-resistant chrome and chrome-nickel stainless steel sheets, sheets and strips for pressure vessels
ASTM A240/A240M 309HNb Material Chemical Composition
The chemical composition of the ASTM A240/A240M 309HNb steel are as follows:
| Element | Min | Max |
|---|---|---|
| Nickel (Ni) | 12.0000 | 16.0000 |
| Chromium (Cr) | 22.0000 | 24.0000 |
| PhOsphorus (P) | - | 0.0450 |
| Sulfur (S) | - | 0.0300 |
| Manganese (Mn) | - | 2.0000 |
| Silicon (Si) | - | 0.7500 |
| Carbon (C) | 0.0400 | 0.1000 |
ASTM A240/A240M 309HNb Material Mechanical Properties
Impact strength is a measure of the ability of a material to absorb sudden impacts and shocks without breaking or deforming. This ASTM A240/A240M 309HNb steel typically has a high impact strength, allowing it to withstand shocks and sudden impacts without sustaining any damage or deforming. High impact strength is essential for use in construction applications where it may encounter sudden forces or impacts.
The mechanical properties of the ASTM A240/A240M 309HNb steel are as follows:
| YieldRp0.2 | ≤ 175 (MPa) |
| TeileRm | ≤ 812 (MPa) |
| ImpactKV/Ku | 11(J) |
| ElongationA | 21% |
| Reduction in cross section on fractureZ | 33% |
| As-Heat-Treated Condition | Solution and Aging, Annealing, Ausaging, Q+T,etc |
| Brinell hardness (HBW) | 133 |
ASTM A240/A240M 309HNb Material Thermal Properties
The thermal performance parameters of the ASTM A240/A240M 309HNb steel are as follows:
| Temperature (°C) | 43 | 165 | 637 |
| Modulus of elasticity (GPa) | - | 793 | - |
| Mean coefficient of thermal expaion ×10-6/(°C) | - | - | 21 |
| Thermal conductivity (W/m·°C) | - | 14.3 | 22.2 |
| Specific thermal capacity (J/kg·°C) | - | 222 | - |
| Specific electrical resistivity (Ω mm²/m) | 0.22 | - | - |
| Deity (kg/dm³) | - | - | 214 |
| Poisson’s coefficient, ν | - | - | 432 |
ASTM A240/A240M 309HNb Material Machining Technology
When machining ASTM A240/A240M 309HNb steel, chip formation should be monitored closely to ensure that no warping or surface defects occur. Chip breakers may be used to help reduce chip formation, while depth of cut, feed rate, and cutting speed should all be set to minimize the load applied to the tool.