Provided is an + titanium alloy welded pipe excellent in the strength and the rigidity in the pipe longitudinal direction, the + titanium alloy welded pipe having a composition consisting of, in mass %, Fe: 0.8% to 1.5%, N: 0.02% or less, and the balance: Ti and impurities, and satisfying Q shown in Formula (1) being 0.34 to 0.55. A tensile strength in a pipe longitudinal direction is more than 900 MPa and a Young's modulus in the pipe longitudinal direction is more than 130 GPa.

Q=[O]+2.77[N]+0.1[Fe](1)

where [Fe], [O], and [N] represent the amounts of the respective elements contained [mass %].

A steel material containing 0.01% to 0.07% C, 0.40% or less Si, 0.5% to 1.4% Mn, 0.1% or less Al, 0.01% to 0.15% Nb, 0.1% or less V, 0.03% or less Ti, and 0.008% or less N on a mass basis, Nb, V, and Ti satisfying Nb+V+Ti<0.15, Cm satisfying 0.12 or less, is heated to a heating temperature of 1,100 C. to 1,250 C., finish-rolled in such a way that the accumulative rolling reduction at a temperature of 930 C. or lower is 40% to 85% and the finished rolling temperature is 760 C. to 870 C., cooled to a cooling stop temperature of 500 C. or lower in terms of surface temperature at an average cooling rate of 30 C./s to 200 C./s in terms of thickness-wise center temperature, naturally cooled for more than 10 s after cooling is stopped, and coiled at a coiling temperature of 400 C. to 620 C.

A method for manufacturing a long length of coiled metal tubing or the like using friction stir welding. Successive lengths of metal strip are friction stir welded using a three-pass welding technique to eliminate any edge defects in the resulting strip. The method includes one or more three-pass friction stir welding routines, each of which includes a first pass performed using a tool having a first rotational direction and a spiral bit pattern corresponding to the first rotational direction; a second pass using a tool having a second rotational direction and a spiral bit pattern corresponding to the second rotational direction; and a third pass using a tool having said second rotational direction and a spiral bit pattern corresponding to the second rotational direction.

A helically wound tubular structure formed from helically wound sheet metals is disclosed. The tubular structure has a first sheet metal helically wound about a longitudinal axis. A second sheet metal having voids disposed therein is helically wound about the longitudinal axis and coaxially about the first sheet metal. A third sheet metal is helically wound about the longitudinal axis and coaxially about the first sheet metal and the second sheet metal.

Systems, methods, and devices relating to an additively manufactured multilayered structure. The additively manufactured multilayered structure may be provided by unspooling a material roll of laminate material using a roller system. A welding device may be used to apply welds between layers of the laminate material to distribute a loading between the layers during use.

A method of manufacture for a reinforced pipe (10), including the steps of, providing a first metal plate (1), having a thickness t; bending the first metal plate (1) along a bending line to form a helix (30), wherein the pitch of the helix (30) is substantially equal to the width of the plate; and wherein two consecutive turns of the helix (30) are in contact at a seam (20); welding the helix along the seam (20) forming a pipe; and welding at least a first metal stiffening element (2) to the pipe, forming a reinforced pipe (10).