Positioning device for measuring circumferences or circumferential arc lengths of larger caliber steel pipes

The utility model discloses a positioning device for measuring circumferences or circumferential arc lengths of larger caliber steel pipes. The positioning device comprises a support, and an axial positioning portion and a circumferential positioning portion are arranged at the bottom of the support; the axial positioning portion is provided with an axial positioning line; the circumferential positioning portion is provided with two circumferential positioning points with are mutually separated at a certain distance; one of the two circumferential positioning points coincides with a horizontal axial positioning line; a connection line of the two circumferential positioning points is perpendicular to the axial positioning line; and gaps exist between the plane of the two circumferential positioning points and the horizontal axial positioning line and the support. The positioning device for measuring circumferences and circumferential arc lengths of larger caliber steel pipes has the advantages that the accuracy of sample positioning can be improved, the operation process is simple, working strength of outdoor pipeline measurement and pipe body sample data extraction can be reduced apparently, the positioning device can be applied to axial and circumferential positioning of steel pipes with different manufacture processes and pipe diameters, the structure is simple, the cost is low, the device is convenient to carry, and the like.