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The main reasons for the low plasticity and ductility of maraging steel 00N18K9M5T in large sections are the coarse-grained structure resulting from heating for hot working and the precipitation of carbides or titanium carbonitrides in the form of a network in the grain boundaries. 2.To eliminate the carbide and titanium carbonitride precipitates in the form of networks and agglomerates and also to refine the grains it is necessary to use a special heat treatment to dissolve the carbonitride precipitates at 1200° and higher, with rapid cooling from this temperature (in water), followed by triple recrystallization at 900-970° with cooling in water (or oil or fused salts). Such heat treatment substantially increases the plasticity and ductility of the steel and also the resistance to repeated static loading. [ABSTRACT FROM AUTHOR]

Steel 1, with σ = 260−280 kg/mm, retains high local plasticity even in notched samples, but has a high crack sensitivity. Steel 2, with σ = 235−245 kg/mm, has a relatively low crack sensitivity under static load. Additional studies of the structural strength are needed to determine the practical applications of steels 2 and 3. [ABSTRACT FROM AUTHOR]

Low-temperature thermomechanical treatment considerably improves the mechanical properties of 1Kh12NVMFA and VNS-6 steels. Low-temperature thermomechanical treatment followed by tempering at secondary hardness temperatures produces a particularly favorable combination of properties. Low-temperature thermomechanical treatment increases not only the resistance to rupture but also the resilience. [ABSTRACT FROM AUTHOR]

Thermal stabilization is associated with changes in the lattice structure the nature of which is obscure. A relaxation of stress peaks possibly takes place in small regions or else an annihilation of transformation nuclei. [ABSTRACT FROM AUTHOR]