Heat treatment method for steel pieces with high impact strength and application of steel pieces

The invention discloses a heat treatment method for steel pieces with high impact strength and application of the steel pieces. The heat treatment method for the steel pieces with high impact strength comprises the following steps of: (1) preparing heat treatment: heating the steel pieces to the temperature of 930+/-10 DEG C together with a furnace at the speed of less than 150 DEG C per hour, preserving the heat for 3 to 3.5 hours, discharging the steel pieces out of the furnace, and cooling to room temperature through air; and (2) normalizing: heating the steel pieces to the temperature of 860+/-10 DEG C together with the furnace at the speed of less than 150 DEG C per hour, preserving the heat for 3 to 3.5 hours, discharging the steel pieces out of the furnace, and cooling to room temperature through air. By the method, many defects of the prior art are overcome, adverse effects of acicular ferrite and stacked latticed thick pearlite tissues in the steel pieces on the impact toughness are overcome, and coo