Structure and properties of some low-carbon alloyed weldable steels

1. Low-carbon alloyed steels with a martensite structure differ from steels with a bainite structure (if they are compared at close values of σ0.2) by a considerably higher impact strength at test temperatures from +20 to −60°C. This is explained by a coarser bainite structure differentiation and formation of austenite-martensite islets during cooling from austenization temperatures in bainite steels. 2. Of the investigated steels the 07Kh3GNM martensite class steel has the better properties; it requires no hardening in liquid media and has a packet structure of martensite in cross sections to 80 mm after cooling or austenization and cooling in air.