Further investigation of critical events in cleavage fracture of C-Mn base and weld steel

Journal Article · Mon Mar 01 04:00:00 EST 1993 · Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States)

DOI:https://doi.org/10.1007/BF02656634· OSTI ID:6353733

Chen, J H; Zhu, L; Wang, G Z; Wang, Z ^[1]

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1. Gansu Univ. of Tech., Lanzhou (China)

In this work, an investigation of the critical event in cleavage fracture of C-Mn base and weld steel was carried out. The fracture surfaces and the remaining cracks in the vicinities of notches and precracks in the double-notched specimens (DNBs) and precracked crack opening displacement (COD) test specimens unloaded prior to fracture were observed in detail. The results demonstrate that critical events are different in notched and precracked specimens even if they are made of identical materials. For the notched specimens with the radius of notch roots from 0.075 to 0.45 mm, critical events in cleavage fracture are the propagation of the ferrite grain-sized microcracks (FCs) into the neighboring ferrite grains. However, for the precracked specimens fractured at [minus] 110 C, critical events are the propagation of the second-phase particle-sized microcracks (SCs) into matrix ferrite grains. For the precracked specimens tested at [minus]70 C, critical events could be the propagation of either SCs or FCs depending on the blunted width of precrack prior to fracture. The cleavage fracture at [minus]196 C is controlled by the nucleation of the microcrack; there were no remaining cracks found in specimens unloaded prior to fracture. With a drop in the test temperature or decrease in the radius of notch root, the length of the critical crack decreases.

• OSTI ID: 6353733
• Journal Information: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States), Journal Name: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States) Vol. 24:3; ISSN 0360-2133; ISSN MTTABN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
CARBON ADDITIONS
CLEAVAGE
CRACK PROPAGATION
CRACKS
FAILURES
FERRITE
FRACTURE PROPERTIES
FRACTURES
IRON ALLOYS
IRON BASE ALLOYS
MECHANICAL PROPERTIES
MICROSTRUCTURE
NOTCHES
SIZE
STEELS
TEMPERATURE RANGE
TEMPERATURE RANGE 0065-0273 K