ArcelorMittal has been granted a patent for a steel sheet coated with a nickel-zinc coating. The steel sheet has a specific microstructure and chemical composition, including residual austenite and martensite. The coating also includes optional elements such as bainite, ferrite, cementite, and pearlite. The patent claims the steel sheet’s unique composition and microstructure. GlobalData’s report on ArcelorMittal gives a 360-degree view of the company including its patenting strategy. Buy the report here.
According to GlobalData’s company profile on ArcelorMittal, photovoltaic roof tiles was a key innovation area identified from patents. ArcelorMittal's grant share as of June 2023 was 1%. Grant share is based on the ratio of number of grants to total number of patents.
Steel sheet coated with nickel-zinc and specific microstructure
A recently granted patent (Publication Number: US11680331B2) describes a steel sheet with a specific composition and microstructure, as well as a method for its manufacture and its use in spot welded joints and automobile vehicle parts.
The steel sheet described in the patent consists of a steel substrate with a coating comprising 10 to 40% nickel and the remaining balance being zinc. The steel substrate has a unique microstructure, which includes 1 to 50% residual austenite, 1 to 60% martensite, and 10 to 40% bainite. The bainite component of the microstructure consists of 10 to 20% lower bainite, with the possibility of 0 to 15% upper bainite and 0 to 5% carbide-free bainite. Additionally, the steel sheet may contain elements such as ferrite, cementite, and pearlite. The coating is directly in contact with the steel sheet and has a thickness between 5 to 15 µm, preferably between 5 to 10 µm.
The patent also covers spot welded joints made using the steel sheet. The joint consists of the steel sheet described above and a second metal sheet, which can be another steel sheet or an aluminum sheet. The joint is designed to have less than 2 cracks with a size above 100 µm, and the longest crack should have a length below 250 µm. The patent also mentions the possibility of including a third metal sheet in the spot welded joint.
Furthermore, the patent describes the use of the steel sheet in automobile vehicle parts. These parts can be manufactured using the coated steel sheet obtained from the method described in the patent. The method involves providing an annealed steel substrate with a specific chemical composition, followed by a coating deposition process using vacuum deposition or electro-plating methods. The annealing process can be performed in a continuous annealing method, and the atmosphere during annealing may contain 1 to 30% H2 at a dew point between -10 and -60°C.
Overall, this patent presents a novel steel sheet composition and microstructure, along with a method for its manufacture and its application in spot welded joints and automobile vehicle parts. The unique properties of the steel sheet and its potential use in various automotive applications make it an interesting development in the field of steel materials.