Steel material for thermal cutting using oxygen

Abstract

A steel material for thermal cutting using oxygen, which has a chemical composition that contains, in mass%, 0.06 to 0.20% of Si, 0.010 to 0.033% of P, and more than 0.02 to 0.08% of Al and that satisfies P / Si >= 0.12 and Al / Si <= 0.60, and which has, on the surface, a scale wherein an Si-rich region having an Si concentration of 0.4% or more is present in the form of a layer and an Al-rich region having an Al / Si ratio of 0.3 or more is present in the form of a layer on the surface-layer side of the Si-rich region.

Description

technical field [0001] The present invention relates to a steel material for thermal cutting using oxygen, and specifically relates to a steel material for thermal cutting using oxygen that can be cut at high speed by using laser, plasma, or gas. In particular, it relates to a steel material having a surface rolling scale (oxidized film on a metal surface) formed when the steel material is rolled. Background technique [0002] Through the remarkable technological progress of laser cutting machines in recent years, laser cutting machines can not only be used to cut thin plates with a thickness of 3.2 mm or less, but also can be used to cut thick plates with a thickness of 30 mm. Therefore, laser cutting machines are widely used to cut thick plates. Compared with the gas cutting machine, the laser cutting machine has fewer safety problems and is suitable for use under the condition of unmanned operation at night. For nighttime unmanned operation using a laser cutting machine...

AI Technical Summary

Problems solved by technology

[0022] Like the methods of Patent Document 4 and Patent Document 5, the scale adhesiveness is improved by adding various elements, but there is no regulation on the scale itself, which greatly affects the laser cutting performance, and stable laser cutting is not guaranteed. cut off

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