US 12,281,375 B2
Al plated welded pipe for hardening use and al plated hollow member and method for producing same
Jun Maki, Tokyo (JP); Soshi Fujita, Tokyo (JP); and Toyomitsu Nakamura, Tokyo (JP)
Assigned to NIPPON STEEL CORPORATION, Tokyo (JP)
Filed by NIPPON STEEL CORPORATION, Tokyo (JP)
Filed on Sep. 7, 2023, as Appl. No. 18/463,110.
Application 18/463,110 is a division of application No. 16/753,961, granted, now 11,807,924, previously published as PCT/JP2017/041697, filed on Nov. 20, 2017.
Prior Publication US 2023/0416888 A1, Dec. 28, 2023
Int. Cl. C22C 38/54 (2006.01); B23K 11/00 (2006.01); B23K 35/02 (2006.01); B23K 35/30 (2006.01); C21D 9/08 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/06 (2006.01); C22C 38/42 (2006.01); C22C 38/44 (2006.01); C22C 38/48 (2006.01); C22C 38/50 (2006.01); C23C 2/26 (2006.01); C23C 2/28 (2006.01); C25D 3/44 (2006.01); C25D 7/04 (2006.01); B23K 101/06 (2006.01); B23K 103/04 (2006.01)
CPC C22C 38/54 (2013.01) [B23K 11/002 (2013.01); B23K 35/0261 (2013.01); B23K 35/3053 (2013.01); C21D 9/08 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/02 (2013.01); C22C 38/06 (2013.01); C22C 38/42 (2013.01); C22C 38/44 (2013.01); C22C 38/48 (2013.01); C22C 38/50 (2013.01); C23C 2/26 (2013.01); C23C 2/28 (2013.01); C23C 2/29 (2022.08); C25D 3/44 (2013.01); C25D 7/04 (2013.01); B23K 2101/06 (2018.08); B23K 2103/04 (2018.08)] 1 Claim
OG exemplary drawing
 
1. A method for producing an Al plated hollow member comprising:
a heating step of heating by a heating temperature of 850° C. or more an Al plated electric resistance welded steel pipe for hardening use comprising a base material made of a tubular steel plate and an electric resistance welded zone provided at a seam portion of the steel plate and extending in a longitudinal direction of the steel plate, wherein
the base material contains, by mass %,
C: 0.06 to 0.50%,
Si: 0.01 to 0.80%,
Mn: 0.60 to 3.00%,
P: 0.050% or less,
S: 0.050% or less,
Al: 0.10% or less,
O: 0.006% or less,
N: 0.020% or less,
Ti: 0.01 to 0.10%,
B: 0 to 0.1000%,
Nb: 0 to 0.10%,
V: 0 to 0.30%,
Cr: 0 to 0.50%,
Mo: 0 to 0.50%,
Ni: 0 to 0.50%,
Cu: 0 to 0.50%,
Ca: 0. to 0.005%,
REM: 0 to 0.005% and
a balance of Fe and impurities, and
the base material is further provided with
an intermetallic compound layer positioned on the surface of the steel plate and including an Al—Fe—Si-based intermetallic compound and
an Al plating layer positioned on the surface of the intermetallic compound layer and containing Al and Si;
a forming step of forming the heated Al plated electric resistance welded steel pipe for hardening use into a desired shape; and
a rapid cooling step of rapid cooling the Al plated electric resistance welded steel pipe for hardening use formed into the desired shape by an average cooling rate of 20° C./s or more, wherein
the following formula (1) and formula (2) are satisfied, wherein X (μm) is a thickness of the intermetallic compound layer, Y (μm) is a thickness of the Al plating layer, t (mm) is a pipe thickness of the steel pipe, D (mm) is an outside diameter of the steel pipe, and HR (° C./s) is an average rate of temperature rise from ordinary temperature to a peak temperature −50° C. set at the time of hot forming:
Y/X≥α×t/D  (1)
α=168×HR−0.45  (2).