The Effect of Solution Heat Treatment and Aging Treatment on the Mechanical Properties of Backward Extruded A6061 Alloy for Pressure Vessels

摘要

Mechanical properties and precipitation behavior of backward extruded 6061 Al alloy for pressure vessel were investigated using tensile test, transmission electron microscopy (TEM) and differential scanning calorimeter (DSC). In this study, solution heat treatment (SHT) was performed at 535 deg C for 30-90 min and aging treatment was conducted at 177 and 190 deg C for 1-7 h. Maximum tensile strength of 36.6 kgf/mm~2 and yield strength of 33.29 kgf/mm~2 were achieved at the aging time of 5 h at 190 deg C. TEM observation showed that fine needle-like beta" phase which has 35-45 nm of length was uniformly distributed in the aged 6061 Al alloy specimen. From tensile test, TEM and DSC analysis, it is expected that aging time of 2-5 h at 190 deg C is suitable for the extruded A6061 used as pressure vessels.