Why is the cutting edge of the chisel is hardened and tempered?

The cutting edge of a chisel is hardened and tempered to enhance its durability and cutting performance. Hardening increases the hardness of the steel, allowing it to maintain a sharp edge and resist wear during use. Tempering follows hardening to reduce brittleness, making the chisel less prone to chipping or breaking under pressure. This combination ensures that the chisel can effectively cut through materials while maintaining structural integrity.