Abstract:Since there is a single-valued reverse“C”shape relation between the displayed values of low frequency WJF-38 type micro-computer-based automatic metal material separator and the hardness of 2014 aluminium alloy after solid solution treatments at different temperatures and natural aging, moreover, the parts without sufficient solid solution, the over-burnt parts and the hardening crack parts respectively appear at the top and bottom of the reverse“C”shape relationship curve, the hardness of the 2014 aluminium alloy can be quantitatively determined by the WJF-38 instrument. Its Brinell hardness, Rockwell hardness and Vickers hardness values can be directly displayed. The parts without sufficient solid solution, the over-burnt parts and the hardening cracked parts can also be accurately separated by using the WJF-38 instrument. Furthermore, there is also a reverse“C”shape relation between the hardness of 2014 aluminium alloy after artificial aging treatment and the displayed value of the WJF-38 instrument. The precision of the hardness tested by the WJF-38 instrument is about HRB±1.3, and the separating speed can reach 1 500 parts per hour.

Key words: aluminium alloy　heat-treatment　quality　nondestructive testing