Development of RCR-processed Ti-Nb steel for shiphull structural application

Book · Sun Dec 31 04:00:00 EST 1995

OSTI ID:234239

Choo, W Y; Lee, S W ^[1]

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1. Pohang Iron and Steel Co. (Korea, Republic of). Technical Research Labs.

To improve the mechanical properties and productivity of steel plate, the effects of RCR (Recrystallization controlled rolling) process and the Nb addition on the properties of 490MPa tensile strength steel plates were investigated by using low carbon-0.015Ti-(0.00--0.08Nb) steels. During reheating and RCR rolling, Ti-Nb steels showed smaller austenite grain size than Ti steel, due to the strong effect of fine (Ti,Nb)N particles on preventing grain growth. Dissolved Nb in austenite just after hot rolling was very effective in decreasing the Ar{sub 3} temperature and thus retarding the austenite({gamma})/ferrite({alpha}) transformation. Also, Nb addition resulted in the precipitation of NbC carbide in ferrite grains. Through the combined effects of recrystallization controlled rolling schedule and increased hardenability by Nb addition, RCR plate comprised a favorable microstructure of very fine ferrite grains and a large amount of evenly distributed hard phases, and showed as good a strength/toughness balance as TMCP plate. Furthermore, RCR plates had a significant merit of high productivity, owing to the considerably high finish rolling temperature around 1,000 C. In ship building industries, for the purpose of energy saving, the use of high strength steel has increased to reduce the weight of ship.

• OSTI ID: 234239
• Report Number(s): CONF-951026--; ISBN 0-87170-555-9
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
36 MATERIALS SCIENCE
ENERGY CONSUMPTION
EXPERIMENTAL DATA
LOW ALLOY STEELS
MECHANICAL PROPERTIES
METALLURGICAL EFFECTS
MICROSTRUCTURE
NIOBIUM
NIOBIUM ADDITIONS
ROLLING
SHIPS
WEIGHT