Patent application number | Description | Published |
20110008546 | PROCESSES FOR PRODUCING HIGH-STRENGTH HOT-DIP GALVANIZED STEEL SHEET AND HIGH-STRENGTH GALVANNEALED STEEL SHEET - A method for manufacturing a high strength hot-dip galvanized steel sheet includes: heating a steel sheet in a CGL, the steel sheet including on a mass percent basis, as chemical components, 0.005% to 0.12% of C, 0.7% to 1.8% of Si, 0.5% to 2.8% of Mn, 0.1% or less of P, 0.07% or less of S, 1.0% or less of Al, 0.008% or less of N, and the balance being Fe and incidental impurities; annealing at 700-940° C. for 15-600 seconds; cooling to 440-550° C. at 3° C./s or more; dipping the steel sheet at 440-550° C. into a hot-dip galvanizing bath at a temperature of 440 to 500° C. for 200 seconds or less to perform hot-dip galvanizing. By the method described above, a high strength hot-dip galvanized steel sheet having a tensile strength level of 590 MPa, which has good coating appearance and superior formability, is obtained. | 01-13-2011 |
20110253263 | HOT-DIP GALVANIZED STEEL SHEET AND MANUFACTURING METHOD THEREOF - A galvanized steel sheet includes a zinc plating layer which is disposed on a steel sheet containing 0.01% to 0.15% C, 0.001% to 2.0% Si, 0.1% to 3.0% Mn, 0.001% to 1.0% Al, 0.005% to 0.060% P, and 0.01% or less S on a mass basis, the remainder being Fe and unavoidable impurities, and which has a mass per unit area 20 g/m | 10-20-2011 |
Patent application number | Description | Published |
20100112377 | GALVANIZED HIGH STRENGTH STEEL SHEET AND METHOD FOR PRODUCING THEREOF - A high-strength galvanized steel sheet is provided which has a tensile strength of a level of about 590 MPa and superior formability, including a coating with good appearance. The galvanized steel sheet includes a base steel and a galvanized coating layer formed over the surface of the base steel. The galvanized steel sheet has a chemical composition containing 0.005% to 0.12% of C, 0.7% to 2.7% of Si, 0.5% to 2.8% of Mn, 0.1% or less of P, 0.07% or less of S, 1.0% or less of Al, 0.008% or less of N, and the balance being Fe and inevitable impurities on a mass basis, and a microstructure constituted of at least 90% of ferrite and 2% to 10% of martensite on an area basis. The ferrite has a Vickers hardness of 120 or more on average, and an inclusion is precipitated from the grain boundary with a length of 50% or less relative to the entire length of the grain boundary in the surface layer of the base steel with a depth of 3 μm from the interface between the coating layer and the base steel. | 05-06-2010 |
20120090737 | HIGH-STRENGTH HOT-DIP GALVANIZED STEEL SHEET AND METHOD FOR PRODUCING SAME - A method for producing a high-strength hot-dip galvanized steel sheet includes a steel sheet containing, in percent by mass, 0.01% to 0.18% of C, 0.02% to 2.0% of Si, 1.0% to 3.0% of Mn, 0.001% to 1.0% of Al, 0.005% to 0.060% of P, 0.01% or less of S, and the balance being Fe and incidental impurities, and a galvanized coating layer on each surface of the steel sheet with a coating weight of 20 to 120 g/m | 04-19-2012 |
20120118439 | HIGH-STEEL GALVANIZED STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME - A high-strength galvanized steel sheet has a low YP, good stretch flangeability, and excellent corrosion resistance and contains, on a percent by mass basis, more than 0.015% to less than 0.10% of C, 0.5% or less of Si, 1.0% to 1.9% of Mn, 0.015% to 0.050% of P, 0.03% or less of S, 0.01% to 0.5% of sol. Al, 0.005% or less of N, less than 0.40% of Cr, 0.005% or less of B, less than 0.15% of Mo, 0.4% or less of V, and less than 0.020% of Ti, in which 2.2≦[Mneq]≦3.1 and [% Mn]+3.3[% Mo]≦1.9, and [% Mn]+3.3 [% Mo])/(1.3[% Cr]+8[% P]+150B*)<3.5 are satisfied. | 05-17-2012 |
Patent application number | Description | Published |
20110217569 | GALVANIZED STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME - A galvanized steel sheet includes a basal steel sheet (BSS) containing C: 0.01-0.15%, Si: 0.001-2.0%, Mn: 0.1-3.0%, Al: 0.001-1.00, P: 0.005-0.060%, and S≦0.01% (all % by mass), balance is Fe and unavoidable impurities; zinc plating layers on both sides of the BSS with 20-120 g/m | 09-08-2011 |
20120180909 | HIGH STRENGTH COLD ROLLED STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME - A multiphase steel sheet has a steel composition containing, in percent by mass, more than 0.015% to less than 0.100% of carbon, less than 0.40% of silicon, 1.0% to 1.9% of manganese, more than 0.015% to 0.05% of phosphorus, 0.03% or less of sulfur, 0.01% to 0.3% of soluble aluminum, 0.005% or less of nitrogen, less than 0.30% of chromium, 0.0050% or less of boron, less than 0.15% of molybdenum, 0.4% or less of vanadium, 0.02% or less of titanium, wherein [Mneq] is 2.0 to 2.8, the balance being iron and incidental impurities. | 07-19-2012 |
20140102596 | HIGH STRENGTH COLD ROLLED STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME - A method of manufacturing a high strength cold rolled steel sheet includes hot-rolling and cold-rolling a steel slab annealing the steel sheet at an annealing temperature of 750° C. to 830° C.; subjecting the steel sheet to first cooling at an average cooling rate of 3° C./sec to 40° C./sec in a temperature range from the annealing temperature to 480° C.; subjecting the steel sheet to second cooling at an average cooling rate of 8° C./sec to 80° C./sec in a temperature range from 480° C. to Tc (° C.) given by formula (6): | 04-17-2014 |
Patent application number | Description | Published |
20120018060 | HIGH-STRENGTH GALVANIZED STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME - Provided is a method for manufacturing a high-strength galvanized steel sheet, made from a steel sheet containing Si and/or Mn, having excellent exfoliation resistance during heavy machining. When a steel sheet containing 0.01% to 0.18% C, 0.02% to 2.0% Si, 1.0% to 3.0% Mn, 0.001% to 1.0% Al, 0.005% to 0.060% P, and 0.01% or less S on a mass basis, the remainder being Fe and unavoidable impurities, is annealed and galvanized in a continuous galvanizing line, a temperature region with a furnace temperature of A° C. to B° C. (600≦A≦780 and 800≦B≦900) is performed at an atmosphere dew-point temperature of −5° C. or higher in a heating process. | 01-26-2012 |
20130174946 | HIGH STRENGTH STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME - A method for manufacturing such steel sheet includes continuous annealing of a steel sheet which includes, in terms of mass %, C at 0.01 to 0.18%, Si at 0.4 to 2.0%, Mn at 1.0 to 3.0%, Al at 0.001 to 1.0%, P at 0.005 to 0.060% and S at ≦0.01%, the balance being represented by Fe and inevitable impurities, in such a manner that the dew point of the atmosphere is controlled to become not more than −45° C. during the course of soaking when the annealing furnace inside temperature is in the range of not less than 820° C. and not more than 1000° C. as well as that the dew point of the atmosphere is controlled to become not more than −45° C. during the course of cooling when the annealing furnace inside temperature is in the range of not less than 750° C. | 07-11-2013 |
20130280551 | HIGH STRENGTH GALVANIZED STEEL SHEET EXHIBITING EXCELLENT FATIGUE PROPERTY AND METHOD FOR MANUFACTURING THE SAME - A high strength galvanized steel sheet having tensile strength of 590 MPa or more which is excellent in fatigue property in punching work, and a manufacturing method thereof are provided. The microstructure includes a ferrite phase having an average grain diameter of 15 μm or less and an area fraction of 60% or more and a martensite phase having an area fraction of 5 to 40%, and an amount of one or more kinds of oxide selected from a group consisting of Fe, Si, Mn, Al, P, Nb, and Ti generated on a surface layer portion of the steel sheet within 100 μm in a steel-sheet-side depth direction from a surface of a base steel sheet directly below a galvanized layer is less than 0.060 g/m | 10-24-2013 |
20130306203 | HIGH STRENGTH STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME - The invention provides a high strength steel sheet which exhibits excellent chemical convertibility and corrosion resistance after electrodeposition coating even in the case where the steel sheet has a high Si content, and a method for manufacturing such steel sheets. The method includes continuous annealing of a steel sheet which includes, in terms of mass %, C at 0.01 to 0.18%, Si at 0.4 to 2.0%, Mn at 1.0 to 3.0%, Al at 0.001 to 1.0%, P at 0.005 to 0.060% and S at ≦0.01%, the balance being represented by Fe and inevitable impurities, while controlling the dew-point temperature of the atmosphere to become not more than −40° C. when the annealing furnace inside temperature is in the range of not less than 750° C. | 11-21-2013 |
20130327452 | HIGH STRENGTH STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME - The invention provides a high strength steel sheet which exhibits excellent chemical convertibility and corrosion resistance after electrodeposition coating even in the case where the steel sheet has a high Si content, and a method for manufacturing such steel sheets. The method includes continuous annealing of a steel sheet which includes, in terms of mass %, C at 0.01 to 0.18%, Si at 0.4 to 2.0%, Mn at 1.0 to 3.0%, Al at 0.001 to 1.0%, P at 0.005 to 0.060% and S at ≦0.01%, the balance being represented by Fe and inevitable impurities, while controlling the dew-point temperature of the atmosphere to become not less than −10° C. when the heating furnace inside temperature is in the range of not less than A° C. and not more than B° C. during the course of heating (A: 600≦A≦780, B: 800≦B≦900). | 12-12-2013 |
Patent application number | Description | Published |
20150047751 | HIGH STRENGTH STEEL SHEET AND METHOD OF MANUFACTURING THE SAME - A high strength steel sheet is formed of steel having the composition containing by mass % over 0.015% and less than 0.100% C, less than 0.50% Si, over 1.0% and less than 2.0% Mn, 0.05% or less P, 0.03% or less S, 0.01% or more and 0.3% or less sol. Al, 0.005% or less N, less than 0.35% Cr, 0.0010% or more and 0.0050% or less B, less than 0.15% Mo, less than 0.030% Ti, and iron and unavoidable impurities as a balance, wherein the steel satisfies 2.1≦[Mneq]≦3.1, the microstructure of the steel includes a ferrite and a second phase, a volume fraction of the second phase is set to 2.0 to 12.0%, a total ratio of a volume fraction of martensite and a volume fraction of retained γ to the volume fraction of second phase is 60% or more, and the number of carbides which are present within ferrite particles, have an aspect ratio of 3.0 or less and have a diameter of 0.25 to 0.90 μm is set to 10000 pieces/mm | 02-19-2015 |