Springer Online Journal Archives 1860-2000
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Conclusions 1. The fracture of steels with ferrite-pearlite and troostomartensite structures occurs with mixed relief, separate sections of which have individual signs typical of the fracture of a given structure-cleavage facets with a riverine pattern for ferrite and troostite, facets of pearlitic cleavage for pearlite, fine polyhedrons and facets of intergranular cleavage for martensite. 2. The amount of pearlitic cleavage in the fracture of steels with a ferrite-pearlite structure is smaller than the amount of pearlite in the steel, which indicates preferential development of cracks in ferrite. 3. A network of cementite in the structure of hypereutectoid steels leads to a sharp reduction of the resistance to fracture due to formation of intergranular fracture. The characteristic feature of intergranular fracture of hypereutectoid steel with a network of cementite is the presence of regularly shaped facets of "boundary" relief in the form of fine cementite platelets. 4. In quenched steel with a martensitic structure, retained austenite increases the toughness due to a change in the character of intragranular cleavage along with an increase in the percentage of intergranular cleavage. The cleavage facets of retained austenite are characterized by fine parallel steps.
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