Steel plate for thick-walled steel pipe, method for manufacturing the same, and thick-walled high-strength steel pipe
US10240226B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 27, 2014 |
| Grant date | Mar 26, 2019 |
| Priority date | — |
| Expiry date | Jul 30, 2035 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/002
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A steel plate has a chemical composition containing, by mass %, C: 0.03% or more and 0.10% or less, Si: 0.05% or more and 0.50% or less, Mn: 1.00% or more and 2.00% or less, P: 0.015% or less, S: 0.005% or less, Mo: 0.20% or less (including 0%), Nb: 0.01% or more and 0.05% or less, and the balance being Fe and inevitable impurities, and, if desired, containing, by mass %, one or more of Al: 0.005% or more and 0.1% or less, Cu: 1.00% or less, Ni: 1.00% or less, Cr: 0.50% or less, and V: 0.05% or less, in which Pcm* (%) (=C+Si/30+(Mn+Cu+Cr)/20+Ni/60+Mo/2+V/10) is 0.20 or less. The steel plate has a volume fraction of bainite in a base material of 50% or more, and has a volume fraction of island martensite (MA) in a coarse-grain region reheated in a dual-phase temperature range of 5.0% or less. A slab having the chemical composition described above that is cast using a continuous casting method is reheated at a specified temperature, hot-rolled, and then subjected to accelerated cooling to a temperature of 550° C. or lower and 250° C. or higher.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.