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1) Seamless is defined as wrought tubular product made without a welded seam. It is manufactured by hot working steel or, if necessary, by subsequently cold finishing the hot worked product.
2) Centrifugally cast is defined as a casting technique in which the mold is rotated during solidification of the casting. b) Welded Processes.
1) Without Filler Metal. Electric weld (applicable to LC30-1512 and full-body heat-treated duplex alloys only). A process of forming a seam by electric-resistance welding, or induction welding wherein the edges to be welded are mechanically pressed together and the heat for welding is generated by the resistance-to-flow of electric current.
2) With Filler Metal.
i) Submerged Arc Welding. A welding process that produces coalescence of metals by heating them with an arc or arcs between a bare metal electrode or electrodes and the work. The arc and molten metal are shielded by a blanket of granular, fusible material on the work. Pressure is not used, and the filler metal is obtained from the electrode.
ii) Gas Metal Arc Welding. A welding process that produces coalescence of metals by heating them with an arc or arcs between a continuous filler metal electrode and the work. Shielding is obtained entirely from an externally supplied gas. Pressure is not used and filler metal is obtained from the electrode.
3) With or Without Filler Metal.
i) Plasma Arc Welding. An arc welding process that produces coalescence of metals by, heating them with a constricted arc between the electrode and the workpiece (transferred arc) or the electrode and the constricting nozzle (nontransferred arc). Shielding is obtained from the hot, ionizing gas issuing from the torch, which may be supplemented by an auxiliary source of shielding gas. Shielding gas may be an inert gas or a mixture of gases. Pressure may or may not be used and filler metal may or may not be supplied.
ii) Gas Tungsten Arc Welding. An arc welding process that produces coalescence of metals by heating them with an arc between a tungsten electrode (nonconsumable) and the work pieces. Shielding is obtained from a gas. Pressure may or may not be used and filler metal may or may not be used.
c) Pipe-making Processes (See Table 3).
1) Seamless. Seamless pipe is produced by the seamless process defined above in 5.1.
2) Centrifugally Cast. Centrifugally cast pipe is produced by the centrifugal casting process defined above in 5.1 a) 2). The entire inner surface of centrifugally cast pipe shall be machined. The outer surface may be machined as well, when agreed upon between the purchaser and the manufacturer.
3) Electric Weld. Electric-welded pipe is defined as having one longitudinal seam produced by the electric welding process as defined in 5.1 b) 1).
4) Submerged Arc. Submerged arc welded pipe is defined is having one longitudinal seam produced by the automatic submerged arc welding process as defined in 5.1 b) 2) i). At least one pass shall be on the inside and one pass on the outside. All end welding of submerged arc welded pipe, if not done by automatic submerged arc welding, shall be done by a procedure and a welder qualified in accordance with Annex C of this specification.
5) Gas Metal Arc. Gas metal arc welded pipe is defined as having one longitudinal seam produced by the continuous gas metal arc welding process as defined in 5.1 b) 2) ii). At least one pass shall be on the inside and one pass on the outside. 6) Combination Welding. Combination welded pipe is defined as pipe having one longitudinal or double seam produced by a combination of welding processes defined in 5.1 b) 2) and 5.1 b) 3).
7) Double Seam. Double seam pipe is defined as pipe having two longitudinal seams formed by welding. The location of the seams shall be approximately 180° apart. All requirements specified for the welding process used shall be applicable to double seam pipe. All weld tests shall be performed after forming and welding.
d) Tack Welding. A tack weld is defined as a weld made to hold parts of a weldment in proper alignment until the final welds are made. Tack welds may be by any of the processes described in 5.1 b). They shall be removed by machining or remelted by subsequent arc welding. They are not subject to the subsequent weld requirements of this specification.