The invention discloses a marking device and method used for a
steel tube elbow. The marking device comprises two positioning base assemblies and a marking ruler, wherein each positioning base
assembly comprises a base
cushion block, a limiting plate, a T-shaped block and a fastening bolt, the base
cushion block is equipped with a V-shaped slot for placing a
steel tube and a T-shaped slot in the
perpendicular direction, the limiting plate is connected with the T-shaped block and is mounted in the T-shaped slot, and can move up and down along the T-shaped slot; the marking ruler comprises a fastening
screw cap, a left ruler and a right ruler, the left end of the right ruler is connected with the right end of the left ruler, the fastening
screw cap is used for fixing an angle position formedby the left ruler and the right ruler, and length scales for measuring a marking distance are arranged on the ruler edge of the marking ruler; during marking operation, the
steel tube elbow is horizontally placed in the V-shaped slots of the two base
cushion blocks, so that the limiting plates move along the T-shaped slots until the limiting plates are in contact with the steel tube
elbow and arefixed; and the marking ruler is adjacent to the limiting plates, the fastening
screw cap is screwed up, scales on the marking ruler are read, and blanking dimensions are marked. The marking device has the advantages of being simple in structure, convenient to use, high in reliability, wide in range of application and the like.