Boron-containing steel sheet with excellent hardenability and method of manufacturing same

Abstract

The present invention provides a boron steel sheet including components of C: 0.20 mass% or more and 0.45 mass% or less, Si: 0.05 mass% or more and 0.8 mass% or less, Mn: 0.5 mass% or more and 2.0 mass% or less, P: 0.001 mass% or more and 0.04 mass% or less, S: 0.0001 mass% or more and 0.006 mass% or less, Al: 0.005 mass% or more and 0.1 mass% or less, Ti: 0.005 mass% or more and 0.2 mass% or less, B: 0.001 mass% or more and 0.01 mass% or less, N: 0.0001 mass% or more and 0.01 mass% or less, and the balance including Fe and inevitable impurities, wherein a mean concentration of solid B in an area from a surface to a depth of 100 [mu] m is 10 ppm or more.

Description

technical field [0001] The invention relates to a boron-added steel plate with excellent hardenability and a manufacturing method thereof. [0002] This application is based on and claims priority to Japanese application No. 2009-063603 filed on March 16, 2009, and the content thereof is incorporated herein. Background technique [0003] In the past, carbon steel plates have been widely used as raw materials for automotive parts such as chains, gears, and clutches, general industrial machinery parts, and tools such as saws and cutting tools. These parts are hardened by heat treatment such as quenching and tempering after forming the carbon steel plate into a product shape. [0004] Therefore, in carbon steel sheets, from the viewpoint of ensuring excellent workability and reducing alloy costs, a B-added carbon steel sheet has been developed that relatively reduces the amount of C or alloy elements and ensures hardenability by adding boron (B), such as disclosed in Patent D...

AI Technical Summary

Problems solved by technology

If BN is formed in the steel, the solid-solution B decreases, so the effect of improving hardenability by B cannot be ensured, and there is a problem that the desired hardness cannot be obtained during quenching after forming

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