STEEL SHEET HAVING EXCELLENT WELDABILITY

Abstract

Disclosed is a steel sheet, containing: Si: 0.20-2% (the term “%” herein means “mass %”, the same is true hereinbelow), Mn: 1-2.5%, a total mass of Si and Mn being 1.5% or more, and 0: 0.002% or less (exclusive of 0%), C: 0.02-0.25%, P: 0.1% or less (exclusive of 0%), S: 0.05% or less (exclusive of 0%), Al-0.02-0.2%, and N: 0.0015-0.015%. The steel sheet of the invention can be advantageously used for forming wide beads even in high-speed arc welding of 100 cm/min or higher.

Description

Claims

1. A steel sheet, comprising: Si: 0.20-2% (the term “%” herein means “mass %”, the same is true hereinbelow),Mn: 1-2.5%, a total mass of Si and Mn being 1.5% or more, andO: 0.002% or less (exclusive of 0%),C: 0.02-0.25%,P: 0.1% or less (exclusive of 0%),S: 0.05% or less (exclusive of 0%),Al: 0.02-0.2%, andN: 0.0015-0.015%.

2. The steel sheet of claim 1, wherein a thickness of an inner oxide layer existing in a surface layer of the steel sheet is 5 μm or less.

3. The steel sheet of claim 1 further comprising at least one element selected from the group consisting of Cr: 0.03-2%, Mo: 0.03-1%, and B: 0.0003-0.005%.

4. The steel sheet of claim 1 further comprising at least one element selected from the group consisting of Nb: 0.005-0.1%, Ti: 0.005-0.3%, V: 0.005-5%, and W: 0.005-0.5%.

5. The steel sheet of claim 1 further comprising Cu: 0.03-0.5% or less.

6. The steel sheet of claim 1 further comprising at least one of: Ca: 0.0005-0.005% and REM (rare earth elements): 0.0005-0.005%.

7. The steel sheet of claim 1 further comprising Zr and Mg: 0.0005-0.005% in total.

8. The steel sheet of claim 1 further comprising Co: 0.03-1%.

9. The steel sheet of claim 5 further comprising Ni: 0.015-0.5%.