Abstract: A system and method for adjusting dipping time in a continuous steel pipe manufacturing line. The system manufactures a steel pipe of which inner and outer faces or any one face thereof is subjected to molten metal-plating from a steel sheet in a continuous manufacturing line, and includes an inner-face plating performing part for molten metal-plating by pouring molten metal to the upper side of the steel sheet corresponding to the inner face of the steel pipe, a steel pipe forming part that obtains a continuous steel pipe by continuously cold-forming the steel sheet subjected to the inner-face plating into a tubular shape and seam-welding a longitudinal end face joint portion of the steel sheet formed in the steel pipe, and an outer-face plating performing part for molten metal-plating by dipping the outer face of the steel pipe into the molten metal, in which a dipping length of the molten metal is adjusted in the inner-face plating performing part and/or the outer-face plating performing part.

Abstract: [Problems] To provide a process for producing a thermal sprayed, metal plated steel tube having a metal layer substantially uniform and favorable over the whole surface in a highly productive manner. [Means for solving] A process for producing a metal tube comprising continuously forming a metal plate composed of a first component into a tubular shape and continuously welding its butted ends to form the metal tube, wherein, after the continuous welding, a metal layer composed of a second component which is different from the first component is formed by thermal spraying directly over the surface of the metal tube, the metal layer having no discontinuities in the circumferential and lengthwise directions. Especially it is preferred that the process comprises a process step of making the thickness distribution of the metal layer more uniform after formation of the thermal sprayed metal layer over the external surface.

Abstract: A system and method for adjusting dipping time in a continuous steel pipe manufacturing line. The system manufactures a steel pipe of which inner and outer faces or any one face thereof is subjected to molten metal-plating from a steel sheet in a continuous manufacturing line, and includes an inner-face plating performing part for molten metal-plating by pouring molten metal to the upper side of the steel sheet corresponding to the inner face of the steel pipe, a steel pipe forming part that obtains a continuous steel pipe by continuously cold-forming the steel sheet subjected to the inner-face plating into a tubular shape and seam-welding a longitudinal end face joint portion of the steel sheet formed in the steel pipe, and an outer-face plating performing part for molten metal-plating by dipping the outer face of the steel pipe into the molten metal, in which a dipping length of the molten metal is adjusted in the inner-face plating performing part and/or the outer-face plating performing part.

Abstract: To provide a process for producing a thermal sprayed, metal plated steel tube having a metal layer substantially uniform and favorable over the whole surface in a highly productive manner. [Means for solving] A process for producing a metal tube comprising continuously forming a metal plate composed of a first component into a tubular shape and continuously welding its butted ends to form the metal tube, wherein, after the continuous welding, a metal layer composed of a second component which is different from the first component is formed by thermal spraying directly over the surface of the metal tube, the metal layer having no discontinuities in the circumferential and lengthwise directions. Especially it is preferred that the process comprises a process step of making the thickness distribution of the metal layer more uniform after formation of the thermal sprayed metal layer over the external surface.

Abstract: [Problems] To provide a process for producing a thermal sprayed, metal plated steel tube having a metal layer substantially uniform and favorable over the whole surface in a highly productive manner. [Means for solving] A process for producing a metal tube comprising continuously forming a metal plate composed of a first component into a tubular shape and continuously welding its butted ends to form the metal tube, wherein, after the continuous welding, a metal layer composed of a second component which is different from the first component is formed by thermal spraying directly over the surface of the metal tube, the metal layer having no discontinuities in the circumferential and lengthwise directions. Especially it is preferred that the process comprises a process step of making the thickness distribution of the metal layer more uniform after formation of the thermal sprayed metal layer over the external surface.