1, the impact on austenitizing - most of the alloying elements (except nickel, cobalt) are slowing the austenitizing process. So the heat treatment needs more than carbon steel heating temperature and longer insulation time. - Carbide should not be decomposed.

2, the impact on the size of austenite grain - most of the alloying elements have aroused the role of austenite grain growth. But manganese and boron on the contrary, can promote the austenite grain growth, so, in addition to manganese steel, alloy steel is not easy to overheat when heated. This will help to obtain fine martensite after quenching; also conducive to the appropriate increase in heating temperature, so that more of the alloying elements in the austenite to increase the hardenability and improve the mechanical properties of steel.

3, the impact of alloying elements on the austenite transition - in addition to cobalt, all alloying elements are C curve to the right, reducing the critical cooling rate of steel to improve the hardenability of steel (Figure 7-4). Some alloying elements also change the shape of the C curve. In addition, most of the alloying elements also make the Ms point drop.