US 12,331,407 B2
Coated steel sheet with thin aluminium alloy coating and coating method thereof
Hongliang Yi, Liaoning (CN); Shu Zhou, Shanghai (CN); and Xiaochuan Xiong, Jiangsu (CN)
Assigned to IRONOVATION MATERIALS TECHNOLOGY CO., LTD., Jiangsu (CN)
Appl. No. 18/008,576
Filed by IRONOVATION MATERIALS TECHNOLOGY CO., LTD., Jiangsu (CN)
PCT Filed Jul. 20, 2020, PCT No. PCT/CN2020/102906
§ 371(c)(1), (2) Date Dec. 6, 2022,
PCT Pub. No. WO2021/248635, PCT Pub. Date Dec. 16, 2021.
Claims priority of application No. 202010509706.6 (CN), filed on Jun. 8, 2020.
Prior Publication US 2023/0235439 A1, Jul. 27, 2023
Int. Cl. C23C 2/12 (2006.01); B21D 22/02 (2006.01); B32B 15/01 (2006.01); B32B 15/04 (2006.01); B32B 15/18 (2006.01); B32B 15/20 (2006.01); C21D 8/02 (2006.01); C21D 9/46 (2006.01); C22C 21/00 (2006.01); C22C 21/02 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/08 (2006.01); C22C 38/12 (2006.01); C22C 38/14 (2006.01); C22C 38/16 (2006.01); C22C 38/18 (2006.01); C22C 38/20 (2006.01); C22C 38/22 (2006.01); C22C 38/24 (2006.01); C22C 38/26 (2006.01); C22C 38/28 (2006.01); C22C 38/32 (2006.01); C22C 38/34 (2006.01); C22C 38/38 (2006.01); C22C 38/40 (2006.01); C22C 38/42 (2006.01); C22C 38/44 (2006.01); C22C 38/46 (2006.01); C22C 38/48 (2006.01); C22C 38/50 (2006.01); C22C 38/54 (2006.01); C22C 38/58 (2006.01); C23C 2/02 (2006.01); C23C 2/20 (2006.01); C23C 2/26 (2006.01); C23C 2/28 (2006.01); C23C 28/02 (2006.01); C23C 30/00 (2006.01)
CPC C23C 2/12 (2013.01) [B21D 22/022 (2013.01); B32B 15/012 (2013.01); B32B 15/04 (2013.01); B32B 15/043 (2013.01); B32B 15/18 (2013.01); B32B 15/20 (2013.01); C21D 8/0205 (2013.01); C21D 8/0278 (2013.01); C21D 9/46 (2013.01); C22C 21/00 (2013.01); C22C 21/02 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/08 (2013.01); C22C 38/12 (2013.01); C22C 38/14 (2013.01); C22C 38/16 (2013.01); C22C 38/18 (2013.01); C22C 38/20 (2013.01); C22C 38/22 (2013.01); C22C 38/24 (2013.01); C22C 38/26 (2013.01); C22C 38/28 (2013.01); C22C 38/32 (2013.01); C22C 38/34 (2013.01); C22C 38/38 (2013.01); C22C 38/40 (2013.01); C22C 38/42 (2013.01); C22C 38/44 (2013.01); C22C 38/46 (2013.01); C22C 38/48 (2013.01); C22C 38/50 (2013.01); C22C 38/54 (2013.01); C22C 38/58 (2013.01); C23C 2/02 (2013.01); C23C 2/0224 (2022.08); C23C 2/20 (2013.01); C23C 2/26 (2013.01); C23C 2/29 (2022.08); C23C 28/02 (2013.01); C23C 28/021 (2013.01); C23C 28/023 (2013.01); C23C 30/00 (2013.01); C23C 30/005 (2013.01); Y10T 428/12438 (2015.01); Y10T 428/12451 (2015.01); Y10T 428/12472 (2015.01); Y10T 428/12736 (2015.01); Y10T 428/12757 (2015.01); Y10T 428/12764 (2015.01); Y10T 428/12951 (2015.01); Y10T 428/12958 (2015.01); Y10T 428/12972 (2015.01); Y10T 428/12979 (2015.01); Y10T 428/24942 (2015.01); Y10T 428/2495 (2015.01); Y10T 428/24959 (2015.01); Y10T 428/24967 (2015.01); Y10T 428/24975 (2015.01); Y10T 428/26 (2015.01); Y10T 428/263 (2015.01); Y10T 428/264 (2015.01); Y10T 428/265 (2015.01)] 22 Claims
OG exemplary drawing
 
1. A coated steel sheet with an aluminium alloy coating for hot stamping, comprising a substrate steel sheet and the aluminium alloy coating coated on at least one surface thereof,
wherein the substrate steel sheet comprises the following constituents by weight: 0.05˜0.45% C, 0.5˜10% Mn, 0˜0.01% B, 0˜0.4% Nb+Ti+V, 0.01˜2% Si, 0.01˜2% Al, 0.01˜5% Cr+Ni+Mo+Cu and 0˜2% Cr, 0˜2% Ni, 0˜2% Mo and 0˜2% Cu, and the balance of Fe and unavoidable impurity elements,
wherein a total coating thickness of the aluminium alloy coating is 5˜14 μm,
wherein the aluminium alloy coating comprises: a FeAlSi inhibitive layer adjacent to the substrate steel sheet; and an Al alloy layer outside the FeAlSi inhibitive layer,
wherein a thickness of the FeAlSi inhibitive layer is no more than 60% of the total coating thickness of the aluminium alloy coating, and the thickness of the FeAlSi inhibitive layer is 1.5˜6 μm,
wherein, at a location within 2 μm from an interface between the FeAlSi inhibitive layer and the substrate steel sheet to an interior of the substrate steel sheet, diameters of Kirkendall voids are no more than 2.5 μm, wherein a number of Kirkendall voids with a diameter of no less than 0.5 μm and no more than 2.5 μm does not exceed 15 per 35 μm, and
wherein the number of Kirkendall voids is determined by the following: in a field of view of an SEM image of a vertical cross-section at the location, the number of Kirkendall voids within a length of 35 μm are counted, and the diameter of each Kirkendall void is determined by: in the field of view, a longest diameter and a shortest diameter of the Kirkendall void are measured and the diameter of the Kirkendall void is equal to half of a sum of the longest diameter and the shortest diameter.