Combination formula plug suitable for steel pipe tensile sample

The utility model discloses a combination formula plug suitable for steel pipe tensile sample, combination formula plug includes the plug overcoat and the interior axle of two symmetries, the internal surface of plug overcoat is semicircle vertebra shape, and the surface includes a plurality of rectangle faces, the inside cone shape hole that forms when two plug overcoats are put together, the external diameter when just two plug overcoats are put together slightly is less than the internal diameter of steel pipe tensile sample, interior axle entire body be the cone, just with cone shape hole phase -match, interior axle both ends central point puts and respectively sets up a screw hole, the utility model discloses a screw rod and screw hole threaded connection, the conical design of the interior axle of combination simultaneously utilizes the screw rod to draw interior to take out interior axle fast, and after interior axle took out, two plug overcoats dropped in the twinkling of an eye, just so saved and app