Precipitation and fine structure in medium-carbon vanadium and vanadium/niobium microalloyed steels

Journal Article · Wed Nov 01 00:00:00 EST 1989 · Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (USA)

DOI:https://doi.org/10.1007/BF02666663· OSTI ID:7156504

Thompson, S W; Krauss, G ^[1]

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1. AMAX, Advanced Steel Processing and Products Research Center, Dept. of Metallurgical and Materials Engineering, Colorado School of Mines, Golden, CO (US)

This paper reports hot-rolled and continuously cooled, medium-carbon microalloyed steels containing 0.2 or 0.4 pct C with vanadium (0.15 pct) or vanadium (0.15 pct) plus niobium (0.04 pct) additions investigated with light and transmission electron microscopy. Energy dispersive spectroscopy in a scanning transmission electron microscope was conducted on precipitates of the 0.4 pct C steel with vanadium and niobium additions. The vanadium steels contained fine interphase precipitates within ferrite, pearlite nodules devoid of interphase precipitates, and fine ferritic transformation twins. The vanadium plus niobium steels contained large Nb-rich precipitates, precipitates which formed in cellular arrays on deformed austenite substructure and contained about equal amounts of niobium and vanadium, and V-rich interphase precipitates. Transformation twins in the ferrite and interphase precipitates in the pearlitic ferrite were not observed in either of the steels containing both microalloying elements. Consistent with the effect of higher C concentrations on driving the microalloying precipitation reactions, substructure precipitation was more frequently observed in the 0.4C-V-Nb steel than in the 0.2C-V-Nb steel, both in the ferritic and pearlitic regions of the microstructure. Also, superposition of interphase and substructure precipitation was more frequently observed in the high-C-V-Nb steel than in the similar low-C steel.

• OSTI ID: 7156504
• Journal Information: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (USA), Vol. 20A:11; ISSN 0360-2133
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CARBON STEELS
MICROSTRUCTURE
AUSTENITIC STEELS
CHEMICAL COMPOSITION
COOLING
DEFORMATION
FERRITE
HOT PRESSING
NIOBIUM ADDITIONS
PHASE TRANSFORMATIONS
PRECIPITATION
TRANSMISSION ELECTRON MICROSCOPY
VANADIUM ALLOYS
ALLOYS
CARBON ADDITIONS
CRYSTAL STRUCTURE
ELECTRON MICROSCOPY
FABRICATION
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS WORKING
MICROSCOPY
NIOBIUM ALLOYS
PRESSING
SEPARATION PROCESSES
STEELS
360102* - Metals & Alloys- Structure & Phase Studies
360103 - Metals & Alloys- Mechanical Properties
360101 - Metals & Alloys- Preparation & Fabrication