Cleavage fracture of microalloyed forging steels

Journal Article · Wed Feb 01 04:00:00 EST 1995 · Scripta Metallurgica et Materialia

DOI:https://doi.org/10.1016/S0956-716X(99)80071-5· OSTI ID:231114

Linaza, M A; Romero, J L; Rodriguez-Ibabe, J M; Urcola, J J ^[1]

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1. ESII de San Sebastian (Spain)

Microalloying in medium C forging steels together with new processes such as thermomechanical treatments or direct quenching from the finishing forging temperature are being used to avoid expensive heat treatments and to obtain required optimum mechanical properties directly after forging. Good strength levels have been obtained without difficulty but for the same strength level, toughness is improved in quenched + tempered steels. In recent years, efforts have been concentrated on improving the toughness by refining the microstructure, and for that, Ti addition is becoming a common method. Several recommendations are made to obtain the maximum yield of fine TiN precipitates, but a certain proportion of TiN precipitates is usually in a coarse form. These precipitates act as cleavage nucleation sites. The present work reports the influence of TiN particles on cleavage fracture stress in four microalloyed forging steels with ferrite-pearlite microstructures and one with lath martensite structure. The results show that cleavage fracture propagation at liquid nitrogen temperature is controlled by the energy required for the microcrack to trespass the TiN particle-matrix interface.

• OSTI ID: 231114
• Journal Information: Scripta Metallurgica et Materialia, Journal Name: Scripta Metallurgica et Materialia Journal Issue: 3 Vol. 32; ISSN SCRMEX; ISSN 0956-716X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CLEAVAGE
EXPERIMENTAL DATA
FRACTURE PROPERTIES
LOW ALLOY STEELS
METALLURGICAL EFFECTS
TITANIUM
TITANIUM NITRIDES