Circular pipe butt welding rapid positioning device and circular pipe butt welding method

The invention relates to a circular duct butt-welding rapid spotting and locating device and a circular duct butt-welding method. The circular duct butt-welding rapid spotting and locating device comprises a locating sleeve, a clamp device, and a tensioning device, the locating comprises a composite structure of two semi locating sleeve, bilaterally symmetrical tapered bores are arranged in the axial direction, a coaxial line circular hole is arranged between two tapered bores, thereby forming a left step rabbets and a right step rabbets, a plurality of radial step holes connected with the two tapered bores and the circular hole are arranged on the periphery of the locating sleeve; the joint part of the side of the two semi locating sleeves is hinged; the clamp device comprises two ear plates arranged on the two semi locating sleeve and a bolt and nut mechanism. The circular duct butt-welding method utilizes the structural characteristics of the tapered bore and the step rabbet of the device, and combines the