Heavy wall steel material having superior weldability and method for producing the same
OwnerHiroshi Nakajima, Shiro Torizuka +2inventors
InventorsHiroshi Nakajima, Shiro Torizuka, Kaneaki Tsuzaki, Kotobu Nagai
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Abstract
A tough high strength heavy wall steel material having superior weldability is provided, said steel material has a diameter or a side 5 mm or more in length, and comprises oxides 1 μm or less in particle diameter homogeneously dispersed at a dispersion density in a range of from 10,000 to 100,000 particles/mm2 and uniform ferrite grains 2 μm or less in grain diameter formed over the entire plane making a right angle with respect to the rolling direction.
Claims4
A heavy wall steel material having superior weldability, which is a steel material having a diameter or a side 5 mm or more in length and which comprises oxides 1 μm or less in particle diameter homogeneously dispersed at a dispersion density in a range of from 10,000 to 100,000 particles/mm2 and uniform ferrite grains 2 μm or less in grain diameter formed over the entire plane making a right angle with respect to the rolling direction.
A method for producing a heavy wall steel material having superior weldability, which comprises allowing oxide crystals 1 μm or less in particle diameter to form in the texture and uniformly dispersing them at a dispersion density of from 10,000 to 100,000 particles/mm2, rolling the resulting steel material through a hole profile in the temperature range of 400° C. or higher but not higher than the Ac3 transformation point, and subjecting it to a recrystallization treatment to form uniform ferrite grains 2 μm or less in grain diameter over the plane making a right angle with respect to the rolling direction, thereby obtaining a heavy wall steel material having superior weldability and having a diameter or a side 5 mm or more in length.
Dependencies are inferred from the claim text.