Abstract
There is a large demand for high carbon steel as parts of equipments and for machine structural uses and it is generally used as tough structures by heat treatment.
In some cases, however, it is used in as-rolled pearlite structure (for instance, rails for railroads).
The author investigated the effects of structures to impact properties for high carbon steel, by changing the temperature of reheating from 600°C to 1 300°C for sorbite and pearlite prior structures.
The results are as follows. Sorbite is much superipr to pearlite. Finer structure is better in case of the same structure after heat treatment is pearlite, sorbite is better for the structure before heat treatment. When the heating temperature is higher than 1 100°C, the impact properties becomes worse regardless of the prior microstructure.
