Method for producing welded steel pipe and welded steel pipe
AssigneeNippon Steel & Sumitomo Metal Corporation
InventorHidenori Shitamoto
Life of this patent
Estimating the term…
Abstract
Provided is a method for producing a welded steel pipe having excellent buckling resistance. The method for producing a welded steel pipe according to the present embodiment includes steps of: preparing a welded pipe, and expanding the welded pipe over the entire length thereof by using a pipe expanding head such that an undulation wavelength ratio D defined by Formula (1) is not more than 0.8, or not less than 1.8: D=p/λ (1), where p is an undulation wavelength in the axial direction of the welded steel pipe, and λ is a Timoshenko's buckling wavelength as defined by Formula (2): λ=3.44×(r×t)1/2 (2), where r is an inner radius of the welded steel pipe and t is a wall thickness of the welded steel pipe.
Claims3
A method for producing a welded steel pipe, comprising the steps of:
- preparing a welded pipe;
- and
- expanding the welded pipe over an entire length thereof by using a pipe expanding head to form a welded steel pipe such that an undulation wavelength ratio D defined by Formula (1) is not more than 0.8, or not less than 1.8:
- D=p/λ (1)
- where p is an undulation wavelength in an axial direction of the welded steel pipe, and λ is a Timoshenko's buckling wavelength as defined by the following Formula (2):
- λ=3.44×(r×t)1/2 (2)
- where r is an inner radius of the welded steel pipe, and t is a wall thickness of the welded steel pipe.
A welded steel pipe produced by being expanded over an entire length thereof, and having an undulation in an axial direction thereof, wherein
- an undulation wavelength ratio D determined by the following Formula (1) is not more than 0.8, or not less than 1.8:
- D=p/λ (1)
- where p is an undulation wavelength of the welded steel pipe, and λ is a Timoshenko's buckling wavelength as determined by the following Formula (2):
- λ=3.44×(r×t)1/2 (2)
- where r is an inner radius of the welded steel pipe, and t is a wall thickness of the welded steel pipe.
Dependencies are inferred from the claim text.