Hyundai Steel has been granted a patent for a steel reinforcing bar with specific composition and structure. The bar contains carbon, silicon, manganese, phosphorus, sulfur, aluminum, nickel, molybdenum, chromium, copper, nitrogen, iron, and impurities. It has a surface layer of tempered martensite and a core with a mixture of bainite, ferrite, and pearlite. The bar is produced through a specific manufacturing process involving reheating, hot-rolling, and cooling. GlobalData’s report on Hyundai Steel gives a 360-degree view of the company including its patenting strategy. Buy the report here.
According to GlobalData’s company profile on Hyundai Steel, hydrogen fuel cells was a key innovation area identified from patents. Hyundai Steel'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.
Patent granted for a steel reinforcing bar with specific composition and structure
A recently granted patent (Publication Number: US11674196B2) describes a steel reinforcing bar with specific composition and properties. The steel reinforcing bar contains carbon, silicon, manganese, phosphorus, sulfur, aluminum, nickel, molybdenum, chromium, copper, nitrogen, iron, and unavoidable impurities. The bar has a surface layer consisting of tempered martensite and a core with a specific composition of bainite, ferrite, and pearlite. The hardened layer has a depth corresponding to 0.31 to 0.55 times the radius of the bar from the surface. The manufacturing process involves reheating a slab, hot-rolling it, and cooling the surface through a TEMPCORE process.
The steel reinforcing bar satisfies certain mechanical properties. It has a yield strength of 500 MPa or more, a tensile strength/yield strength ratio of 1.15 or more, and an elongation of 10% or more at room temperature. Additionally, it has a uniform elongation of 3% or more at 170°C when measured on an unnotched specimen. The bar also exhibits a notch sensitivity ratio of 1.0 or more at -170°C, which is the ratio of tensile strength of a notched specimen to the yield strength of an unnotched specimen.
Furthermore, the ferrite in the core of the steel reinforcing bar has a specific grain size of 9 to 11 µm.
This patented steel reinforcing bar offers a unique combination of composition and properties. The specific composition and heat treatment process result in a hardened surface layer and a core with a specific distribution of bainite, ferrite, and pearlite. These features contribute to the bar's mechanical properties, including high yield strength, good elongation, and notch sensitivity. The grain size of the ferrite in the core also adds to the overall performance of the bar.
The patented steel reinforcing bar has potential applications in construction and infrastructure projects where high-strength reinforcement is required. Its unique properties can enhance the structural integrity and durability of reinforced concrete structures. The bar's ability to withstand high loads and provide ductility at different temperatures makes it suitable for a wide range of applications.
Overall, this granted patent introduces a novel steel reinforcing bar with specific composition, heat treatment, and mechanical properties. Its unique combination of features makes it a promising material for various construction and infrastructure projects.