TH53192B - High carbon hot rolled steel plates and methods for producing them. - Google Patents

Abstract

DC60 (31/03/48) High Carbon Hot Roll Steel Sheet Yes In terms of mass percentages, 0.10 to 0.7% of carbon, 2.0% or less of silicon, 0.20 to 2.0% of manganese, 0.03% or less of phosphorus, 0.03% or less of sulfur, 0.1% or less. Of Sol. Aluminum, 0.01% or less of nitrogen And the rest is iron and non-toxic impurities. It is unavoidable, and structured Of ferrites with an average grain size of 6 microns or less And carbides with an average grain size of 0.10 microns or more and less than 1.2 microns. Of carbides with a grain size of 2.0 microns or more, 10% or less, the volume ratio of the non-carbide ferrite is 5% or less. The manufacturing method of the hot-rolled high-carbon steel plate has The stages of hot rolling, initial cooling, quenching, coiling, acid wash and annealing, initial cooling Placenta to make the sheet metal Hot roll cools down To the end temperature The cooling rate is in the range from 450 ° C to 600 ° C at a rate of To cool above 120 ° C / s. Second stage cooling To entrap a steel sheet Hot roll In the first step At a temperature from 450 degrees Celsius to 650 degrees Celsius until the curl Hot Rolled Steel Plate, High Carbon In terms of mass percent, 0.10 to 0.7% of carbon, 2.0% or less of silicon, 0.20 to 2.0% of manganese, 0.03% or less of phosphorus, 0.03% or less of sulfur, 0.1%. Or less of Sol Aluminum, 0.01% or less of nitrogen And the rest is iron and non-toxic impurities. It is unavoidable, and structured Of ferrites with an average grain size of 6 mu m or less And carbides with an average grain size of 0.10 mu m or more and less than 1.2 mu m. Of carbides with a grain size of 2.0 mu m or more, 10% or less, the volume ratio of the ferrite without carbide is 5% or less, the production method of hot-rolled ductile iron plate. High carbon has stages of hot rolling, initial cooling, quenching, coiling, acid washing and early annealing. The placenta has to make the steel plate sticky Hot roll cools down To the end temperature There are coolants that range from 450 ํ C to 600 ํ C at a cooling rate higher than 120 ํ C / sec. Second stage cooling To entrap a steel sheet Hot roll In the first step At temperatures from 450 ํ C to 650 ํ C until curling

Claims (2)

High carbon hot rolled mild steel sheets containing, in terms of mass percentage, 0.10 to 0.7 % carbon, 2.0 % or less of silicon, 0.20 to 2.0 % of manganese, 0.03 % or less of phosphorus, 0.03 % or less of sulfur, 0.1 % or less of aluminum, 0.01 % or less of nitrogen and the remainder being iron and unavoidable impurities; ferrites having an average grain size of 6 µm or less and carbides having an average grain size of 0.10 µm or more and less than 1.2 µm; carbides having a volume ratio of 10 % or less in a grain size fraction of 2.0 µm or more; and ferrite without carbides having a volume ratio of 5 % or less. 2. The high carbon hot rolled mild steel sheet of claim 1, furthermore having at least one element selected from the group consisting, in terms of mass percentage, of 0.05 to 1.5 % of chromium and 0.01 to 0.5 % of molybdenum. 3. The high carbon hot rolled mild steel sheet of claim 1, furthermore having at least one element selected from the group consisting, in terms of mass percentage, of 0.005 % or less of boron, 1.0 % or less of copper, 1.0 % or less of nickel and 0.5 % or less of tungsten. 4. The high carbon hot rolled mild steel sheet of claim 2, furthermore having at least one element selected from the group consisting, in terms of mass percentage, of 0.005 % or less of boron, 1.0 % or less of copper, 1.0 % or less of nickel and 0.5 % or less of tungsten. of copper, 1.0 % or less of nickel, and 0.5 % or less of tungsten. 5. High carbon hot rolled steel sheet of any one of claims 1. to 4. Also containing at least one element selected from a group consisting, in terms of mass percentage, of, 0.5 % or less of titanium, 0.5 % or less of niobium, 0.5 % or less of vanadium, and 0.5 % or less of zirconium. 6. High carbon hot rolled steel sheet of claim 1, wherein the silicon content is 0.005 to 2.0 % by mass. 7. High carbon hot rolled steel sheet of claim 6, wherein the silicon content is 0.02 to 0.5 % by mass. 8. High carbon hot rolled steel sheet of claim 1, wherein the manganese content is. 9. The high carbon hot rolled mild steel plate of claim 2, wherein the chromium content is 0.05 to 0.3% by mass. 1 0. The high carbon hot rolled mild steel plate of claim 2, wherein the chromium content is 0.8% to 1.5% by mass. 1 1. The high carbon hot rolled mild steel plate of claim 2, wherein the molybdenum content is from 0.05 to 0.5% by mass. 1. 2. A method for producing high carbon hot rolled mild steel plate, comprising the step of hot rolling the steel which shall consist, in terms of mass percentage, of 0.10 to 0.7% of carbon, 2.0 or less of silicon, 0. 20 to 2.0% of manganese, 0.03% or less of phosphorus, 0.03% or less of sulfur, 0.1% or less of aluminum sulfate, 0.01% or less of nitrogen, and the remainder of iron and unavoidable impurities at a finishing temperature of (Ar3 - 10°C) or more; applying a preliminary cooling to the hot rolled mild steel plate to the finishing temperature. in the range from 450°C to 600°C at a cooling rate greater than 120°C/s; using a secondary cooling to confine the initially cooled hot rolled mild steel sheet in the temperature range from 450°C to 650°C until coiling; coiling the hot rolled mild steel sheet that has been cooled to a coiling temperature of 600°C or less; applying acid washing to the hot rolled mild steel sheet that has been coiled; and annealing the acid washed hot rolled mild steel sheet at an annealing temperature in the range from 680°C to the transformation point Ac1 1 3. The method of claim 1, 2. wherein the cooling rate in the initial cooling step is in the range from 120 to 700°C/s1 4. The method of claim 1. 2. Where the coil temperature is in the range from 200 °C to 600 °C.