Improvement of fracture toughness of forging steels microalloyed with titanium by accelerated cooling after hot working

Journal Article · Mon Nov 01 04:00:00 EST 1993 · Scripta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-716X(93)90112-6· OSTI ID:5789330

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

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1. ESII de San Sebastian and CEIT (Spain)

Ti addition is becoming common practice in the fabrication of many grades of engineering steels. In general it is used with the aim of refining the microstructure through the inhibiting effect to grain coarsening exerted by small TiN precipitates. Although a number of recommendations are made for obtaining the maximum yield of fine TiN precipitates, nonetheless a certain proportion of the precipitate volume fraction is usually in the form of coarse TiN precipitates. Several authors suggest that such coarse TiN particles are simply ineffective in pinning the grain boundaries without impairing other properties. In a recent paper it was shown that these coarse TiN particles act as cleavage nucleation sites, impairing the fracture toughness of steel with coarse ferrite-pearlite microstructures. The present work reports further fracture toughness results and fracture mechanisms for Ti treated microalloyed forging steels. They show that after hot working and accelerated cooling transforming the austenite mainly in an acicular microstructure, ductile rupture results without any cleavage nucleated in the coarse TiN particles, as occurred when the same material had a coarse ferrite-pearlite microstructure.

• OSTI ID: 5789330
• Journal Information: Scripta Metallurgica et Materialia; (United States), Journal Name: Scripta Metallurgica et Materialia; (United States) Vol. 29:9; ISSN 0956-716X; ISSN SCRMEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201* -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360203 -- Ceramics
Cermets
& Refractories-- Mechanical Properties
ALLOYS
FABRICATION
FORGING
FRACTURE PROPERTIES
HOT WORKING
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS WORKING
MECHANICAL PROPERTIES
MICROSTRUCTURE
NITRIDES
NITROGEN COMPOUNDS
PNICTIDES
STEELS
TITANIUM COMPOUNDS
TITANIUM NITRIDES
TRANSITION ELEMENT COMPOUNDS