	US 12,264,379 B2
	Steel wire rod having excellent spheroidizing heat treatment properties and method of manufacturing same
Sang-Yoon Lee, Gyeongsangbuk-do (KR); In-Gyu Park, Gyeongsangbuk-do (KR); Jae-Seung Lee, Gyeongsangbuk-do (KR); and Byoung-Gab Lee, Gyeongsangbuk-do (KR)
Assigned to POSCO, Pohang-si (KR)
Appl. No. 17/786,060
Filed by POSCO, Pohang-si (KR)
PCT Filed Dec. 20, 2019, PCT No. PCT/KR2019/018206 § 371(c)(1), (2) Date Jun. 16, 2022, PCT Pub. No. WO2021/125407, PCT Pub. Date Jun. 24, 2021.
Prior Publication US 2023/0027056 A1, Jan. 26, 2023
Int. Cl. C21D 9/52 (2006.01); C21D 1/02 (2006.01); C21D 1/18 (2006.01); C21D 1/32 (2006.01); C21D 6/00 (2006.01); C21D 8/06 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/28 (2006.01); C22C 38/32 (2006.01)

CPC C21D 9/525 (2013.01) [C21D 1/02 (2013.01); C21D 1/18 (2013.01); C21D 1/32 (2013.01); C21D 6/002 (2013.01); C21D 6/005 (2013.01); C21D 8/06 (2013.01); C21D 8/065 (2013.01); C22C 38/001 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/28 (2013.01); C22C 38/32 (2013.01); C21D 2211/005 (2013.01); C21D 2211/009 (2013.01); Y02P 10/25 (2015.11)]

9 Claims

1. A steel wire rod having excellent spheroidizing heat treatment properties, comprising, by weight %:

0.3-0.5% of C, 0.02-0.4% of Si, 1.0-1.5% of Mn, 0.3-0.7% of Cr, 0.003% or less (excluding 0%) of B, less than 0.03% (excluding 0%) of Ti, 0.03% or less (including 0%) of P, 0.01% or less (including 0%) of S, 0.02-0.05% of Al, 0.001-0.01% of N, and a balance of Fe and inevitable impurities,

wherein a microstructure is a complex structure having a main phase of ferrite+pearlite, with one or more of bainite or martensite accounting for 5 area % or less (including 0%), and has an average aspect ratio of cementite of 35 or less in a region at a ⅖-⅗ point of a diameter.