Abstract: Provided is a fuel distribution pipe connected to a fuel pipe and distributes and supplies fuel to a plurality of fuel injection devices, comprising: a tubular base material forming a body of the fuel distribution pipe; and a plating layer formed on a surface of the base material, wherein the base material includes a sealing surface formed on an inner peripheral surface thereof and comes into press-contact with the fuel pipe, and wherein a thickness of the plating layer on the sealing surface is thinner than that of the plating layer on an outer peripheral surface of the fuel distribution pipe.

Abstract: Provided is a fuel distribution pipe connected to a fuel pipe and distributes and supplies fuel to a plurality of fuel injection devices, comprising: a tubular base material forming a body of the fuel distribution pipe; and a plating layer formed on a surface of the base material, wherein the base material includes a sealing surface formed on an inner peripheral surface thereof and comes into press-contact with the fuel pipe, and wherein a thickness of the plating layer on the sealing surface is thinner than that of the plating layer on an outer peripheral surface of the fuel distribution pipe.

Abstract: A pipe fastening structure includes an end member attached to an end part of a metal pipe, and a nut for fastening the end member attached to the metal pipe to a counterpart. In the pipe fastening structure, the end member has a first spherical part to be brought into contact with a sealing surface of the counterpart, a second spherical part formed integrally with the first spherical part so as to be in contact with a sliding surface formed in the nut, and a neck continuous with the second spherical part and having the shape of a straight pipe.

Abstract: A heat treatment method of heat-treating a steel tube provides the steel tube with satisfactory workability and high pressure resistance capable of coping with a recent increasing trend of pressure dealt with by a recent common rail type fuel injection system. A steel tube of a desired size is formed by drawing a material of a steel containing at least vanadium. The steel tube is processed for normalizing by holding the steel tube at high temperatures between 950 and 1000° C. for a predetermined time and slowly cooling the steel tube at a predetermined cooling rate. Then, the steel tube is processed for tempering by heating the steel tube at a temperature between 500 and 700° C. and cooling the steel tube to an ordinary temperature at an optional cooling rate.

Abstract: A pipe fastening structure includes an end member 16 attached to an end part of a metal pipe 10, and a nut 12 for fastening the end member 16 attached to the metal pipe 10 to a counterpart 14. In the pipe fastening structure, the end member has a first spherical part 20 to be brought into contact with a sealing surface 27 of the counterpart 14, a second spherical part 21 formed integrally with the first spherical part 20 so as to be in contact with a sliding surface 25 formed in the nut 12, and a neck 18 continuous with the second spherical part 21 and having the shape of a straight pipe.

Abstract: A heat treatment method of heat-treating a steel tube provides the steel tube with satisfactory workability and high pressure resistance capable of coping with a recent increasing trend of pressure dealt with by a recent common rail type fuel injection system. A steel tube of a desired size is formed by drawing a material of a steel containing at least vanadium. The steel tube is processed for normalizing by holding the steel tube at high temperatures between 950 and 1000° C. for a predetermined time and slowly cooling the steel tube at a predetermined cooling rate. Then, the steel tube is processed for tempering by heating the steel tube at a temperature between 500 and 700° C. and cooling the steel tube to an ordinary temperature at an optional cooling rate.