Abstract: A method for producing a steel material for line pipes including heating a steel having a specific composition to a temperature of 1000° C. to 1200° C.; performing hot rolling such that a cumulative rolling reduction ratio in a non-recrystallization temperature range is 60% or more, a cumulative rolling reduction ratio in a temperature range of (a rolling finish temperature +20° C.) or less is 50% or more, and a rolling finish temperature is the Ar3 transformation point or more and 790° C. or less; subsequently performing accelerated cooling from a temperature of the Ar3 transformation point or more, at a cooling rate of 10° C./s or more, to a cooling stop temperature of 200° C. to 450° C.; and then performing reheating such that the temperature of a surface of the steel plate is 350° C. to 550° C. and the temperature of the center of the steel plate is less than 550° C.

Abstract: In a pneumatic tire are defined: a first imaginary line VL1 passing through a ground contact surface in a meridian cross section of a tread, a second imaginary line VL2 passing through a bottom of a shoulder groove and parallel to VL1, an intersection point P between VL2 and a surface of a shoulder land outward of a ground contact edge T in a lateral direction, and an equatorial plane CL. Given A as a distance in the lateral direction between P and CL, B as a groove depth of the shoulder groove, and C as a distance in the lateral direction between T and CL, 0.80?(B+C)/A?1.15 is satisfied. Given Q as a distance in the lateral direction between CL and an end of a belt ply that has a shorter dimension in the lateral direction, 0.75?Q/C?0.95 is satisfied.

Abstract: In a pneumatic tire are defined: a first imaginary line VL1 passing through a ground contact surface in a meridian cross section of a tread, a second imaginary line VL2 passing through a bottom of a shoulder groove and parallel to VL1, an intersection point P between VL2 and a surface of a shoulder land outward of a ground contact edge T in a lateral direction, and an equatorial plane CL. Given A as a distance in the lateral direction between P and CL, B as a groove depth of the shoulder groove, and C as a distance in the lateral direction between T and CL, 0.80?(B+C)/A?1.15 is satisfied. Given Q as a distance in the lateral direction between CL and an end of a belt ply that has a shorter dimension in the lateral direction, 0.75?Q/C?0.95 is satisfied.

Abstract: A pneumatic tire is provided with a tread portion and side portions. The tread portion includes shoulder main grooves and shoulder land portions. The following are defined in a meridian cross section of the tread portion: a first imaginary line passing through a ground contact surface, a second imaginary line passing through a bottom portion of a shoulder main groove and parallel to the first imaginary line, an intersection point between the second imaginary line and a surface of a shoulder land portion, and a tire equatorial plane. Given A as a distance in the tire lateral direction between the intersection point and the tire equatorial plane, B as a groove depth of the shoulder main groove, and C as a distance in the tire lateral direction between the tire equatorial plane and the ground contact edge, the condition 0.80?(B+C)/A?1.15 is satisfied.

Abstract: In the end-closed pipe of the invention, a pair of half-cylindrical portions are opposed to each other to form a pipe portion, and part of an end portion of each of the half-cylindrical portions is folded or formed into a V-shaped or a U-shaped cross-section to form a half closure portion projecting from an inner surface thereof, and the half closure portions of the two half-cylindrical portions are bonded together so as to form a closure portion at the end portion of the pipe. Two closure portions are formed at the both ends of the pipe, and a partition portion which has same structure as that of the closure portion is formed between the two closure portions. In the heat exchanger header of the invention, a plurality of tube insertion holes are formed in the above end-closed pipe, and are spaced from one another along an axis thereof.

Abstract: In a pipe in which a plate material is formed into a cylindrical shape, and a one-side edge portion and the other-side edge portion are joined to each other to thereby form a pipe body, a fitting convex portion is integrally formed on the one-side edge portion of the pipe body, and a fitting concave portion is integrally formed in the other-side edge portion so that the fitting convex portion is fitted into the fitting concave portion. Further, a top end portion of the fitting concave portion is bent and received in a recess portion formed in the pipe body.

Abstract: In an end-closed pipe of a pair of half-cylindrical portions are opposed to each other to form a pipe portion, and part of an end portion of each of the half-cylindrical portions is folded or formed into a V-shaped or a U-shaped cross-section to form a half closure portion projecting from an inner surface thereof, and the half closure portions of the two half-cylindrical portions are bonded together so as to form a closure portion at the end portion of the pipe. Two closure portions are formed at the both ends of the pipe, and a partition portion which has same structure as that of the closure portion is formed between the two closure portions. In the heat exchanger header a plurality of tube insertion holes are formed in the above end-closed pipe, and are spaced from one another along an axis thereof.

Abstract: In a header pipe for use in a heat exchanger composed of a header pipe body, both ends of which are closed, and a heating medium pipe, one end of which is connected to the header pipe body, on an outer circumferential surface of the header pipe body, there is formed a connecting opening which is open in an axial direction of the header pipe body, and one end portion of the heating medium pipe is inserted into the connecting opening.