A process of heating and cooling to change the metallurgical structure or mechanical properties of magnesium alloys or eliminate residual stress.
Correspondingly, the commonly used heat treatment states of China’s deformed magnesium parts include fully annealed (M), semi-cold work hardening (Y2), quenching (C), quenching + artificial aging (cs), hot deformation + artificial aging (Rs) and Quenching + cold deformation + artificial aging (CYS).
Depending on the needs, China’s cast magnesium alloys also use codes commonly used in some countries to indicate heat treatment states: T2 (annealed), quenched (T4), artificial aging in the as-cast state (T5) and T6 (quenching + artificial aging).
The solution treatment of magnesium machining is carried out in a protective gas or atmosphere (argon, carbon dioxide or sulfur dioxide). The furnace atmosphere should also be well circulated, and is usually quenched in still air.
Magnesium alloys basically have no strengthening effect of natural aging. Some magnesium alloys need to be annealed after welding to eliminate internal stress.
The basic heat treatment conditions and typical systems of deformed magnesium alloys and cast magnesium alloys in China are shown in Tables 1 and 2. Table 1 Basic heat treatment states and typical systems of wrought magnesium alloys in China