6151 alloy was born in the United States in the 1930s. Its prototype alloy, 6051, was listed as a non-alloy by the American Aluminum Association on December 12, 1963. There are still five such alloys currently in use: 6151, 6351,6351A, 6451,6951 alloy. In addition to 6351A for the French alloy, the other are all American alloys. Such alloys are widely used in military weapons for the production of crankcase forgings and rolling rings, mines and machine forgings. All parts that require good forging properties, high strength and good corrosion resistance can be machined with this alloy. Before 1954, it was called 51S in the United States and 6151 in 1954.
The chemical composition of Alloy 6151 is shown in Table 1. The alloy 6951 has the lowest content of Si, equivalent to only about 35% of the other alloys, so its strength properties should be the lowest. However, it contains 0.15% Cu - 0.40% Cu , While other alloys do not contain Cu, so their mechanical properties are almost no major difference.
6151 alloy minimum mechanical properties shown in Table 2, the sample gauge 50mm or 4d (d for the sample diameter). 6151 alloy has no brittleness at low temperature and can be used for processing parts working at extremely low temperature. The tensile strength Rm = 330N / mm2 at 25 ℃, the yield strength Rp0.2 = 298N / mm2, the elongation A = 17% When the temperature dropped to 200 ℃, the performance of the overall increase, respectively, 395N / mm2, 345N / mm2, 20%. 6151 alloy working temperature should not exceed 120 ℃.
The density of 6151 alloy at 20 ℃ is 2700kg / m3; the liquidus temperature is 649 ℃; the solidus temperature is 588 ℃; mean linear expansion coefficient is 21.8μm / (m · k) at -50 ℃ - The average linear expansion coefficient of -100 ℃ is 23.0μm / (m · k), the average linear expansion coefficient is 24.1μm / (m · k) at 20 ℃ -200 ℃, the average linear expansion coefficient is 25.0μm at 20 ℃ -300 ℃ / (M · k).
Equivalent volume of 6151 alloy at 20 ° C Conductivity: 54% IACS for O state material, 42% for T4 state IACS, 45% IACS for T6 state; resistivity at 20 ° C: 32 nΩ · m, T4 for O state material 41nΩ · m in the state of Tn, 38nΩ · m in the T6 state, 895 J / (kg · K) in specific heat capacity at 20 ° C, thermal conductivity of 20 ° C: 205W / (m · k) (M · k); 175W / (m · k) in T6 state.
The 6154 alloy contains 53 g NaCl / L + 3 g H 2 O 2 / L at 25 ° C and has a potential of -0.83 V for the 0.1 N calomel electrode.
6151 alloy annealing specification 413 ℃ / (2h - 3h), with no more than 27 ℃ / h cooling rate with the furnace cooling to 260 ℃, and then baked air-cooled. Solution treatment temperature (510 ℃ - 525 ℃) / 4min, room temperature quenching water, large forgings at 65 ℃ - 100 ℃ water quenching. Artificial aging specification (165 ℃ - 175 ℃) / (8h - 12h). Hot processing temperature 260 ℃ - 480 ℃.