Stable welding structure, method and equipment for cylindrical pieces

The invention discloses a stable welding structure for cylindrical pieces. The stable welding structure comprises a lower welding piece, an upper welding piece and a connecting piece; the upper welding piece is vertically placed above the lower welding piece; the connecting piece is coaxially arranged on the lower part of the upper welding piece in a sleeving mode, the connecting piece is in clearance fit with the upper welding piece, an extension ring integrally formed with the connecting piece is arranged on the peripheral surface of the lower part of the connecting piece, and the extension ring and the connecting piece are coaxial; and an incidence point of oblique laser is positioned in a junction area of the outer edge of the extension ring and the upper end surface of the welding lower piece. The invention further provides a stable welding method for the cylinder pieces and stable welding equipment for the cylinder pieces. The incidence point of the oblique laser in the stable welding structure for the