1.Chemical composition tolerances of Inconel 601
Inconel 601 is a nickel-chromium-iron alloy with controlled additions of aluminum. The typical composition and common tolerances (per ASTM B 166 / B 166M and similar specifications) are as follows (values in weight percent):
Nickel (Ni): 58.0–63.0%
– Primary alloying element; provides high-temperature stability and corrosion resistance.
Chromium (Cr): 21.0–25.0%
– Key for oxidation and corrosion resistance, especially at elevated temperatures.
Iron (Fe): 10.0–15.0%
– Improves fabricability and reduces cost while maintaining good high-temperature properties.
Aluminum (Al): 1.0–1.7%
– Promotes the formation of a dense, adherent Al₂O₃ scale, critical for high-temperature oxidation resistance.
Carbon (C): 0.05–0.15%
– Strengthens the alloy through carbide formation; limited to avoid excessive carbide precipitation and embrittlement.
Manganese (Mn): ≤1.0%
Silicon (Si): ≤0.5%
Copper (Cu): ≤0.5%
Sulfur (S): ≤0.015%
Phosphorus (P): ≤0.02%
These ranges already include the typical manufacturing and analytical tolerances. For precise limits and any special requirements (e.g., for critical high-temperature applications), the relevant ASTM, ASME, or customer specification should be consulted.
2.Typical hardness range of Inconel 601
The hardness of Inconel 601 depends on the heat treatment and cold work condition:
Solution-annealed condition (most common):
– HB (Brinell): 180–240– HRB (Rockwell B): 85–100
– HV (Vickers): ~180–260
After cold working:
– Hardness can increase significantly, e.g., HB up to ~300 or higher, depending on the amount of reduction.
After long-term exposure at high temperatures:
– Some slight softening or age-hardening may occur due to microstructural changes (e.g., carbide precipitation, grain growth), but the overall hardness remains relatively stable in service.
For design or inspection purposes, the solution-annealed hardness range of HB 180–240 is typically specified.
