Calibration device for quickly judging insertion length of reinforcing steel bar of green component

The calibration device comprises an inner sleeve and an outer sleeve, one end of the inner sleeve is arranged in the outer sleeve and is connected with the outer sleeve in a matched and telescopic mode, a limiting cover is arranged at the outer end of the outer sleeve, an axial sliding groove is formed in the surface of the inner sleeve, and the inner sleeve is sleeved with the limiting cover. An axial sliding groove is formed in the inner sleeve, a plurality of size positioning holes are formed in the axial sliding groove, a mark number is arranged on the outer surface of the inner sleeve on one side of each size positioning hole, a ball plunger is further arranged on the outer sleeve, penetrates through the outer sleeve to the inside and abuts against the axial sliding groove in a matched mode, and the ball plunger can axially slide in the axial sliding groove. The axial sliding groove limits the ball head plunger to rotate in the circumferential direction. A limiting protruding part is arranged on the side