Shock-resisting steels are designed to have high impact resistance (toughness), along with other properties such as strength, hardness.
Silicon is a common addition to this class of steels, as it provides tempering resistance and increases toughness.
[1] Applications for shock-resisting steels includes springs, as well as chisels, dies for forging, and punches.
[5] SVCM steel is an alloy of carbon, silicon, chromium, magnesium, nickel, molybdenum and lead.
[6] SVCM+ in addition is quenched and tempered achieving a high hardness (HRC 59).