US 11,655,519 B2
Thermal cycling for austenite grain refinement
James W. Watson, Brownsburg, IN (US); Paul Kelly, Mount Kembla (AU); Mike Schueren, Crawfordsville, IN (US); and Walter N. Blejde, Brownsburg, IN (US)
Assigned to NUCOR CORPORATION, Charlotte, NC (US)
Appl. No. 16/488,437
Filed by NUCOR CORPORATION, Charlotte, NC (US)
PCT Filed Feb. 27, 2018, PCT No. PCT/US2018/019967
§ 371(c)(1), (2) Date Aug. 23, 2019,
PCT Pub. No. WO2018/157136, PCT Pub. Date Aug. 30, 2018.
Claims priority of provisional application 62/464,355, filed on Feb. 27, 2017.
Prior Publication US 2020/0063235 A1, Feb. 27, 2020
Int. Cl. C21D 9/52 (2006.01); C22C 38/48 (2006.01); C22C 38/44 (2006.01); C22C 38/42 (2006.01); C22C 38/06 (2006.01); C22C 38/04 (2006.01); C22C 38/02 (2006.01); B22D 11/00 (2006.01); B22D 11/06 (2006.01); B22D 11/12 (2006.01); C21D 6/00 (2006.01); C21D 1/18 (2006.01); C22C 38/46 (2006.01)
CPC C21D 9/52 (2013.01) [B22D 11/001 (2013.01); B22D 11/0622 (2013.01); B22D 11/1213 (2013.01); C21D 1/18 (2013.01); C21D 6/004 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/42 (2013.01); C22C 38/44 (2013.01); C22C 38/46 (2013.01); C22C 38/48 (2013.01); C21D 2211/008 (2013.01)] 21 Claims
OG exemplary drawing
 
1. A thin metal strip comprising:
an as cast thickness less than 5 mm;
by weight, between 0.20% and 0.35% carbon, less than 1.0% chromium, less than 1.0% nickel, between 0.7% and 2.0% manganese, between 0.10% and 0.50% silicon, between 0.1% and 1.0% copper, less than 0.08% niobium, less than 0.08% vanadium, less than 0.5% molybdenum, silicon killed with less than 0.01% aluminum;
martensite from prior austenite grains, where at least 75% of the prior austenite grains have a grain size equal to or less than 10 μm upon a first thermal cycle.