2results about How to "Fully enriched" patented technology

The invention belongs to the technical field of metallurgy, and particularly relates to 590MPa-grade hot galvanizing dual-phase steel and a production method thereof, and the steel comprises the following chemical components in percentage by mass: 0.02%-0.06% of C, 0.01%-0.03% of Si, 0.90%-1.8% of Mn, less than or equal to 0.025% of P, less than or equal to 0.010% of S, 0.005%-0.010% of Al, 0.05%-0.30% of Cr, 0.05%-0.30% of Mo, less than or equal to 0.0060% of O, 0.010%-0.020% of N, and the balance of Fe and inevitable impurities. The method has the advantages that low carbon-silicon-aluminum and high nitrogen are cooperatively regulated and controlled in component design, and in the hot rolling process, premature precipitation of AlN particles in the hot rolling process is effectively inhibited by controlling the low coiling temperature, so that a large amount of nitrogen is reserved in a hot rolled plate in a solid solution state.

This invention discloses a low-carbon tin-containing free-machining steel and its production method. The weight percentage (wt%) of the chemical composition in the steel is: C 0.06-0.15, Si 0.10-0.30, Mn 1.50-1.80, S 0.40-0.60, P 0.06-0.10, Sn 0.30-0.50, Mn / S≥4.0, Sn / S≥0.80, O: 130-200ppm, with the remainder being iron and unavoidable impurities. This invention, through compositional design, controls Mn / S≥4.0 to improve the spindle morphology of sulfides, and Sn / S≥0.80 to achieve Sn aggregation near sulfides and grain boundaries, as well as aggregation and precipitation in other areas of the material matrix, which is more conducive to improving the material's machinability and reducing turning cracks. The Sn element is added using a combined addition technology of the tundish impact zone and the crystallizer nozzle, which improves the Sn yield.