Joint coating implement and construction method

The invention discloses a joint coating implement and a construction method. The joint coating implement comprises a metal lining plate, an electric heating device and a steel hoop sequentially from inside to outside, the metal lining plate is cylindrical, the head and the tail of the metal lining plate are overlapped, the electric heating device is wrapped outside the metal lining plate, the steel hoop is wrapped outside the electric heating device to be cylindrical, and the head and the tail of the steel hoop are locked through a mechanical locking device. The construction method includes the steps: a, performing surface treatment; b, preheating a steel pipe; c, brushing base coat; d, wrapping and coating a joint coating piece; e, wrapping the metal lining plate; f, wrapping the electric heating device; g, wrapping and locking the steel hoop; h, performing program temperature control; i, demounting the implement. The joint coating implement has the advantages of simplicity, reliability, low cost and low construction expense; the steel hoop is adopted for locking and pressurizing, and huge pressure can be applied in the process of softening and bonding of the joint coating piece, so that strength in bonding of an epoxy layer is improved substantially; peeling strength at 23 DEG C can reach more than 250N/cm, peeling strength at 50 DEG C can reach more than 100N/cm, and the peeling strength at 23 DEG C and at 50 DEG C are more than two and five times that of joint coating through a thermal contraction sleeve or belt respectively.