Alloy K500
Alloy K500, also known as Monel K500, is a precipitation-hardenable nickel-copper alloy. By adding aluminium and titanium and undergoing controlled heating, the alloy forms precipitated particles throughout the matrix, enhancing its properties through age hardening. Alloy K500 demonstrates excellent corrosion resistance in seawater, hydrofluoric acid, sulphuric acid, alkalis, and sour-gas environments (NACE MR1075 compliant). It is well-suited for marine shafts in high-velocity sea water, with low corrosion rates and high strength. Despite initial pitting, it slows down after an initial rapid attack. The alloy is refined through Electro Slag Refining (ESR) for superior material purity, reducing non-metallic inclusions and potential machining difficulties. It also maintains low permeability and nonmagnetic properties down to -150°F (-101°C).
Chemical Composition Limits
| Cr | Ni | Mo | Co | Nb (+Ta) | Ti | V | W | Cu | C | Mn | N | Si | P | S | Fe | Al | |
| Min | – | 63.00 | – | – | – | 0.35 | – | – | 27.00 | – | – | – | – | – | – | – | 2.30 |
| Max | – | – | – | – | – | 0.85 | – | – | 33.00 | 0.25 | 1.50 | – | 0.50 | – | 0.010 | 2.00 | 3.15 |
Mechanical Properties
| Cold Worked & Precipitation Treated | Cold Worked, Solution Treated & Precipitation Treated | Hot Worked & Precipitation Treated | Hot Worked, Solution Treated & Precipitation Treated | ||||||
| Bars up to and including 25mm section size or diameter | Bars between 25-55mm section size or diameter | Bars up to and including 25mm section size or diameter | Bars between 25-55mm section size or diameter | Bars up to and including 110mm section size or diameter | Bars between 110-300mm section size or diameter | Bars up to and including 25mm section size or diameter | Bars between 25-110mm section size or diameter | Bars between 110-300mm section size or diameter | |
| 0.2% Proof Stress | 760 (110) | 690 (100) | 620 (89.9) | 550 (79.8) | 724 (105) | 724 (105) | 500 (72.5) | 585 (84.8) | 500 (72.5) |
| N/mm2 (ksi) | |||||||||
| Tensile Strength, N/mm2 (ksi) | 1000 (145) | 970 (140.6) | 900 (130.5) | 830 (120) | 965 (140) | 965 (140) | 830 (120.3) | 900 (130.5) | 830 (120.3) |
| Elongation, 5.65√S0 and 4D | 14% | 16% | 20% | 20% | 20% | 20% | 15% | 20% | 15% |
| Hardness (Rockwell C) | 27-35 | 27-35 | 27-35 | 27-35 | 27-35 | 27-35 | 27-35 | 27-35 | 27-35 |
| Impact Strength (-29oC or lower) | 27J av (20J min) | 27J av (20J min) | 27J av (20J min) | 27J av (20J min) | 27J av (20J min) | 27J av (20J min) | 27J av (20J min) | 27J av (20J min) | 27J av (20J min) |
Physical Properties
| Density (Kg/m3) | 8430 |
| Magnetic Permeability (20°C) | <1.005 (1.002 typical) |
| Young’s Modulus (kN/mm2) | 179 |
| Specific Electrical Resistance, 20°C (µΩ-m) | 0.62 |
| Mean coefficient of thermal expansion, 20-100°C (m/m/degC) | 13.4 x 10-6 |
| Specific Heat, 20°C (J/kg.K) | 418 |
| Thermal conductivity, 20°C (W/m.K) | 17.5 |
| Curie Temperature (°C) | -90 |
Key Features
- High strength and hardness from sub-zero to elevated temperatures.
- Excellent corrosion resistance in a wide range of environments.
- Resistant to chloride stress corrosion.
- Good resistance to impingement attack
- High fatigue strength in seawater.
- Low magnetic permeability to very low temperatures.
Applications
- High strength and hardness from sub-zero to elevated temperatures.
- Excellent corrosion resistance in a wide range of environments.
- Resistant to chloride stress corrosion.
- Good resistance to impingement attack.
- High fatigue strength in seawater.
- Low magnetic permeability to very low temperatures.