US 11,739,393 B2
Method for producing a steel component having a metal coating protecting it against corrosion
Janko Banik, Altena (DE); Maria Köyer, Dortmund (DE); Dirk Rosenstock, Essen (DE); and Manuela Ruthenberg, Dortmund (DE)
Assigned to ThyssenKrupp Steel Europe AG, Duisburg (DE); and ThyssenKrupp AG, Essen (DE)
Appl. No. 16/647,894
Filed by ThyssenKrupp Steel Europe AG, Duisburg (DE); and ThyssenKrupp AG, Essen (DE)
PCT Filed Oct. 11, 2018, PCT No. PCT/EP2018/077692
§ 371(c)(1), (2) Date Mar. 17, 2020,
PCT Pub. No. WO2019/076720, PCT Pub. Date Apr. 25, 2019.
Claims priority of application No. 10 2017 218 704.2 (DE), filed on Oct. 19, 2017.
Prior Publication US 2020/0216925 A1, Jul. 9, 2020
Int. Cl. C21D 9/48 (2006.01); B21D 22/02 (2006.01); C21D 6/00 (2006.01); C21D 8/04 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/22 (2006.01); C22C 38/26 (2006.01); C22C 38/28 (2006.01); C22C 38/32 (2006.01); C23C 2/06 (2006.01); C23C 2/28 (2006.01); C23C 2/40 (2006.01)
CPC C21D 9/48 (2013.01) [B21D 22/022 (2013.01); C21D 6/002 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 8/0405 (2013.01); C21D 8/0426 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/22 (2013.01); C22C 38/26 (2013.01); C22C 38/28 (2013.01); C22C 38/32 (2013.01); C23C 2/06 (2013.01); C23C 2/28 (2013.01); C23C 2/40 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A method for producing a steel component having a content of diffusible hydrogen Hdiff of up to 0.4 ppm, the method comprising the steps of:
(A) providing a steel product having a coating including, in weight percent (wt. %), 3 to 15 Si, 1 to 3.5 Fe, 0.05 to 5.0 alkali and/or alkaline earth metals, remainder Al and unavoidable impurities, the steel product including, in wt. %:
0.20 to 0.25 C,
0.50 to 3.0 Mn,
0.10 to 0.50 Si,
0.01 to 1.00 Cr,
up to 0.20 Ti,
up to 0.10 Al,
up to 0.10 P,
up to 0.1 Nb,
up to 0.01 N,
up to 0.05 S and
up to 0.1 B,
remainder Fe and unavoidable impurities,
rolling the steel product, on which the coating already is present, to a lower sheet thickness to form a rolled steel product having rolling degree of from 2.5% to 60% and having a rolling degree to sheet thickness ratio (WGB) which is within a range from 0.8 to 200, wherein
the WGB is a dimensionless value being determined according to the following formula:

OG Complex Work Unit Math
wherein, in said formula, the sheet thickness is in mm and is identical to the final thickness of the steel product after rolling,
(B) determining a hydrogen-related furnace parameter value (WOP value) for the rolled steel product on the basis of the rolling degree to sheet thickness ratio (WGB) within a surface spanned by straight connecting paths between points P11 (WGB 0.8, WOP 100) and P13 (WGB 0.8, WOP 800), P13 (WGB 0.8, WOP 800) and P21 (WGB 26, WOP 650), P21 (WGB 26, WOP 650) and P41 (WGB 74, WOP 590), P41 (WGB 74, WOP 590) and P53 (WGB 150, WOP 520), P53 (WGB 150, WOP 520) and P51 (WGB 150, WOP 100) and P51 (WGB 150, WOP 100) and P11 (WGB 0.8, WOP 100) in a coordinate system in which the WOP value is plotted on the y axis and the rolling degree to sheet thickness ratio (WGB) is plotted on the x axis,
(C) treating the rolled steel product at an average furnace temperature Tfurnace (in Kelvin) for a duration tfurnace (in hour), wherein the dew point temperature of the furnace atmosphere of the furnace Tdew point (in Kelvin), the average furnace temperature Tfurnace (in Kelvin) and the duration tfurnace (in hour) are set according to the following equation of general formula (1)
WOP=Tfurnace·log (tfurnace+1.15)+(Tdew point−243.15)1.6 (1)
and
(D) forming the heated rolled steel product from step (C) in a mold while being simultaneously cooled to obtain the steel component.