TH72034B - Hot-rolled high-carbon steel plates and methods for producing them. - Google Patents

Abstract

DC60 (04/11/52) This invention provides a high carbon hot rolled steel sheet. That has excellent flexural properties After stretching and how to produce that The production method of hot rolled high carbon steel sheet consists of a step of hot rolling of steel with composition, as% by mass, 0.2 to 0.7% of carbon, 2% or less of silicon, 2% or less of manganese, 0.03% or less of phosphorus, 0.03% or less of sulfur, 0.01% or less of sol. Aluminum, and 0.01% or less of nitrogen. At the finishing temperature of (Ar3 change point - 20 ° C) or more to form hot-rolled steel sheet, the process of cold-rolled steel sheet heating to a temperature of 650 ° C or less at the Cold at 60 ° C / s to less than 120 ° C / s, step of hot-rolled steel sheet coiling at 600 ° C or less after cooling, and annealing step of hot rolled steel sheet. At a ductile temperature of 640 ° C to the ac1 transition point, the invention provides a high carbon hot-rolled steel sheet. That has excellent flexural properties After stretching and how to produce that The production method of hot rolled high carbon steel sheet consists of a step of hot rolling of steel with composition, as% by mass, 0.2 to 0.7% of carbon, 2% or less of silicon, 2% or less of manganese, 0.03% or less of phosphorus, 0.03% or less of sulfur, 0.01% or less of sol. Aluminum, and 0.01% or less of nitrogen. At finishing temperature of (Ar3 - 20 ํ C) or more to form hot-rolled steel sheet, the process of cold-rolled steel sheet is cooled to a temperature of 650 ํ C or less at the heating rate. Cold at 60 ํ C / sec to less than 120 ํ C / sec, the process of coiling hot rolled steel sheet at 600 ํ C or less after cooling, and the process of hot rolled steel sheet annealing. At a baking temperature of 640 ํ C to the Ac1 transformation point.

Claims (4)

Disclaimer (all) which will not appear on the advertisement page: Amendment 14/11/2018 1. Production method of hot rolled high carbon steel plate, Method includes: Stage of hot rolling of steel with elements containing , As a percentage by mass. 0.2 to 0.7% carbon, 2% or less of silicon, 2% or less of manganese, 0.03% or less of phosphorus, 0.03% or less of sulfur, 0.01% or less of sol. Aluminum, 0.01% or less of nitrogen, and the rest is iron and impurities that cannot be Avoidable At the finished temperature of (Ar3 -20 ํ C) or more to form hot-rolled steel; The process of making hot and cold rolled steel sheet To a temperature of 540 ํ C or more and 650 ํ C or less, at a cooling rate of 60 ํ C / s to less than 120 ํ C / s, the process of hot steel coil coiling at temperature. Curl a few, 400 * C or more and 600 ํ C or less after cooling; And the process of baking. Hot-rolled steel sheet at a ductile temperature of 640 ํ C reached the Ac1 transformation point in 8 hours or more and 80 hours or less. After curl for Make the carbide into a circular shape. (spheroidized) ----------------------------------------------- 1.Method for producing hot-rolled high-carbon steel sheet, method includes: step of rolling steel with composition, in% by mass, 0.2 to 0.7% of carbon, 2% or less of silicon, 2% or Less than that of manganese, 0.03% or less of phosphorus, 0.03% or less of sulfur, 0.01% or less of sol. Aluminum, and 0.01% or less of nitrogen, at the completion temperature. (finishing temperature) of (Ar3 change point - 20 ํ C) or more to form hot-rolled steel sheets; The process of making hot and cold rolled steel sheet To a temperature of 650 ํ C or less, and at a cooling rate of 60 ํ C / sec to less than 120 ํ C / s. Step of hot-rolled steel coiling at 600 ํ C or less after heating. Cold; And the process of baking, hot-rolled steel sheet at a temperature of 640 ํ C to the ac1 transition point after coiling. 2. Production method of hot rolled high carbon steel according to claim 1., where hot rolled steel sheet is cooled to a temperature of 600 ํ C or less at a cooling rate of 80 ํ C / sec to less. 120 ํ C / sec in the cooling stage. And was coiled at a temperature of 550 ํ C or less in the process of coiling. 3. Manufacturing method for hot-rolled high-carbon steel sheet according to Clause 1. or 2., where the composition of the steel still has At least one selected from boron, chromium, nickel, molybdenum, copper, titanium, niobium, tungsten, vanadium and zirconium in the quantity range. The following is% by mass: boron: 0.005% or less, chromium: 3.5% or less, nickel: 3.5% or less, molybdenum: 0.7% or less, copper: 0.1. % Or less, titanium: 0.1% or less, niobium: 0.1% or less, tungsten, vanadium, zirconium: 0.1% or less overall 4. high carbon hot rolled steel plate. Which is a sticky baking material that has been shaped like Hot-rolled spheroidizing annealed material, ductile iron sheet contains: elements containing, in% by mass, 0.2 to 0.7% of carbon, 2% or less of silicon, 2% or less of manganese, 0.03% or less of phosphorus, 0.03% or less of sulfur, 0.01% or less of sol. Aluminum, and 0.01% or less of nitrogen; Where the ferrite grain diameter is 50 (formula) m or less, and the meat ratio Where graferrite had an aspect ratio of 4.0 or greater, 15% or less, where the ferrite grain diameter was the mean grain diameter. That is set by The ferrite grain approximation is a round grain in the image analysis, and the face ratio is the mean of (ellipse major axis) / (ellipse minor axis) determined by the ferrite grain estimation. Is an ellipsoid grain in the image analysis 5. Hot-rolled high-carbon steel plate according to claim 4., where the ratio The area of grain ferrite with a face ratio of 4.0 or more is 10% or less. 6. High carbon hot-rolled steel plate according to the clause. 4. or 5., where the composition of steel is also At least one selected from boron, chromium, nickel, molybdenum, copper, titanium, niobium, tungsten, vanadium and zirconium in the quantity range. The following is% by mass: boron: 0.005% or less, chromium: 3.5% or less, nickel: 3.5% or less, molybdenum: 0.7% or less, copper: 0.1. % Or less, titanium: 0.1% or less, niobium: 0.1% or less, tungsten, vanadium, zirconium: 0.1% or less overall.