Soft magnetic iron

A soft magnetic iron comprising a chemical composition consisting of, in mass %,

• C:
• less than 0.02%,
• Si:
• less than 0.05%,
• Mn:
• more than 0.03% and 0.50% or less,
• P:
• 0.002% or more and 0.005% or less,
• S:
• 0.013% or more and 0.050% or less,
• Al:
• 0.010% or less,
• N:
• 0.0010% or more and 0.0100% or less, and
• B:
• 0.0003% or more and 0.0065% or less,
• and optionally, in mass %, one or more selected from the group consisting of
• Cu:
• 0.20% or less,
• Ni:
• 0.30% or less,
• Cr:
• 0.30% or less,
• Mo:
• 0.10% or less,
• V:
• 0.02% or less,
• Nb:
• less than 0.015%,
• Ti:
• less than 0.010%,
• Pb:
• 0.30% or less,
• Bi:
• 0.30% or less,
• Te:
• 0.30% or less,
• Se:
• 0.30% or less,
• Ca:
• 0.0100% or less,
• Mg:
• less than 0.0050%,
• Zr:
• 0.200% or less, and
• REM:
• 0.0100% or less,
• with a balance consisting of iron and inevitable impurities,
• wherein a magnetic flux density at 100 A/m in a magnetization process with a peak magnetic field of 10,000 A/m is 1.20 T or more, a magnetic flux density at 300 A/m in a magnetization process with a peak magnetic field of 10.000 A/m is 1.50 T or more, and a coercive force measured with a reversal magnetization force of ±400 A/m is 60 A/m or less,
• wherein a critical upset ratio, which is an upset ratio when a crack occurred during successive compression, is 55% or more, and
• wherein a flank wear, which is measured after a cutting work with a cut depth of 0.2 mm, a feed rate of 0.15 mm/rev, a peripheral speed of 300 m/min, wet type, and a length of cut of 1000 m, is 35 μm or less.