UNS K93600, also known as alloy 925, is a nickel-iron-chromium alloy that offers high resistance to corrosion in various environments. The alloy has many chemical, petrochemical, and aerospace applications. This article delves deeper into UNS K93600, including its composition, physical and mechanical properties, hardness, heat treatment, welding, and corrosion resistance.
UNS K93600 Composition
The main components of UNS K93600 are nickel, iron, and chromium, with trace amounts of molybdenum, copper, manganese, silicon, and carbon. The composition gives the alloy high strength, excellent corrosion resistance, and good weldability.
|Cobalt, Co||≤ 1|
|Manganese, Mn||≤ 0.60|
|Molybdenum, Mo||≤ 0.50|
|Chromium, Cr||≤ 0.50|
|Silicon, Si||≤ 0.35|
|Carbon, C||≤ 0.10|
|Phosphorous, P||≤ 0.025|
|Sulfur, S||≤ 0.025|
UNS K93600 Physical Properties
UNS K93600 has a density of 8.14 g/cm³ and a melting point of 1343°C. The alloy exhibits high thermal conductivity and good electrical conductivity. It also has a low coefficient of thermal expansion and good magnetostrictive properties.
|Density||8.11 g/cm3||0.293 lb/in3|
UNS K93600 Mechanical Properties
The mechanical properties of UNS K93600 vary with temperature and heat treatment. The alloy has a tensile strength of 690 MPa at room temperature, which decreases to 380 MPa at 650°C. UNS K93600 also shows excellent fatigue and creep resistance, making it a popular choice for high-stress applications.
|Tensile strength (annealed prior to test)||490 MPa||71100 psi|
|Yield strength (annealed prior to test, @strain 0.200%)||240 MPa||34800 psi|
|Elongation at break (annealed prior to test)||42.0%||42.0%|
UNS K93600 Thermal Properties
|Thermal expansion co-efficient (@20-100°C/68-212°F)||1.50 µm/m°C||0.833 µin/in°F|
|Thermal conductivity||10.0 W/mK||69.4 BTU in/hr.ft².°F|
UNS K93600 Equivalent
- ASTM B388
- DIN 1.3912
- MIL I-16598
- MIL I-23011 Class 7
UNS K93600 Hardness
The hardness of UNS K93600 depends on the heat treatment. In the annealed condition, the alloy has a hardness of 190 HB. However, the hardness can increase to 410 HB when cold working or ageing.
UNS K93600 Heat Treatment
UNS K93600 can be heat treated using several methods, including annealing, solution annealing, and precipitation hardening. Annealing involves heating the alloy to 760-871°C for several hours, followed by slow cooling. Solution annealing involves heating the alloy to 1038-1093°C, followed by rapid cooling. Precipitation hardening involves ageing the solution annealed alloy at 718-760°C for several hours, followed by air cooling.
UNS K93600 Welding
UNS K93600 can be welded using several methods, including gas tungsten arc welding, gas metal arc welding, and submerged arc welding. However, due to the high carbon content of the alloy, it is recommended to use low-carbon filler metals to avoid cracking.
UNS K93600 Corrosion Resistance
UNS K93600 exhibits excellent corrosion resistance in various environments, including seawater, acidic solutions, and high-temperature gases. The alloy is also resistant to stress corrosion, cracking, and pitting corrosion. However, it may be susceptible to intergranular corrosion in certain conditions, such as after welding or long-term exposure to high temperatures.
UNS K93600 is a versatile nickel-iron-chromium alloy with high strength, excellent corrosion resistance, and good weldability. The alloy has various applications in various industries, including chemical, petrochemical, and aerospace. To fully utilize the benefits of UNS K93600, it is important to understand its composition, physical and mechanical properties, hardness, heat treatment, welding, and corrosion resistance.
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