| 摘要 |
PROBLEM TO BE SOLVED: To provide a steel sheet for a welding backing of a steel pipe which can be bent without using a fixture by an operator, and does not fall off on robot welding by suitably setting the remaining sheet thickness and groove pitches. SOLUTION: The steel sheet for a welding backing is formed in such a manner that a group of grooves are arranged in parallel on the parts to be applied to the inner curved face of each curved part in a welding base metal. When the radius of curvature in the curved part is r (mm); the thickness of the steel sheet is t (mm); the remaining sheet thickness is d (mm), the groove width is a (mm); the maximum spacing between the steel sheet and the welding base metal when the steel sheet is bent is s (mm); the angle between groove pitches is 2θ(radian); the central angle of the curved part is D (radian); and the number of the grooves is n1 and n2, the number of the grooves n1 is calculated by n1=ät-(d to d/2)}×D×1/a-1, and the number of grooves 2 is calculated by cosθ=1-s/r, and n2=D/2θ-1. The number of the grooves is set to the higher value in the above n1 and n2, and also to the numerical value with which the groove pitches reach≥2.55 mm. COPYRIGHT: (C)2004,JPO
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