2　Terms and Symbols

2.0.1　Spot Welding

It's a welding process in which electric arc is used as the heating source to melt down the welding joint of a work-piece to form spot-like or discontinuous welds.

2.0.2　High Frequency Longitudinal Welded Pipe

It's a pipe with a longitudinal seam welded by high frequency welding process over the length of the pipe body.

2.0.3　Pipe End Treating

It refers to the non-plastic deformation processing on the pipe ends to provide the plain pipe with ends as required from the product standards.It includes pipe end defect removal，flash trimming，dressing，beveling and the like.However，it does not include end upsetting，sizing，threading，coupling and so on.

2.0.4　Welded Pipe

It's a pipe made of steel sheet or strip which is bent to have a tubular form，with a longitudinal or spiral seam welded over the full length of the pipe body.

2.0.5　Mill Set It's a collection of the process equipment to produce the products in the mix，covering the process of feedstock preparation downstream to the final product storage.

2.0.6　Annual Scheduled Operation Time of Mill Set

It's the yearly calendar time deducting the time required for major，medium and minor maintenance and normal shift change-overs of the mill set.

2.0.7　Annual Available Production Time of Mill Set

It's the annual scheduled operation time deducting the time required for changing the rolls，tools and specifications and shut down of the mill set.

2.0.8　Annual Necessary Production Time of Mill Set

It's the actual time required for the mill set to achieve the annual output as specified in product mix.

2.0.9　Duty Ratio of Mill Set

It's the ratio of the annual necessary production time to the annual available production time of the mill set.

2.0.10　Weight Ratio of Plate or Strip to Product

It's the ratio between the weight of the consumed plate or strip for production of the products of all the sizes specified in the product mix and the total weight of the products by the mill set.

2.0.11　Offline

It's one of the operation modes in which a work-piece（including feedstock and semi-finished pipes）cannot be moved from the production line of the welded pipes in continuous operation to a certain sequence of the line or vice versa without the help of hoisting and transportation equipment or by hand.

2.0.12　Spiral Submerged-arc Welded Pipe

It's a pipe with a spiral seam welded by submerged-arc welding process over the pipe body.

2.0.13　Manual Inspection

It's a process in which the inner and outer surface quality，shape and dimension of a welded pipe are inspected by eyes or simple tools like low-power amplifier，endoscope，gauges，etc.

2.0.14　Online/Inline

It's one of the operation modes in which a work-piece（including feedstock and semi-finished pipes）can be moved from the production line of the welded pipes in continuous operation to a certain sequence of the line or vice versa even without the help of hoisting and transportation equipment or by hand.

2.0.15　Longitudinal Submerged-arc Welded Pipe

It's a pipe with a longitudinal seam welded by submerged-arc welding process over the pipe body.

2.0.16　Automatic Butt Welder It's a welder which can automatically perform butt welding on the head and tail ends of the strip except itsparameter setup and start/stop.

2.0.17　Automatic Inside Flash Trimmer

It's a device which can automatically trim off the flashes from the inside face of the welds except its start/stop and adjustment.

2.0.18　Automatic Outside Flash Trimmer

It's a device which can automatically trim off the flashes from the outside surface of welds except its start/stop and adjustment.

2.0.19　Automatic Submerged-Arc Welder

It's a welder which can automatically perform submerged-arc welding exceptits parameter setup and start/stop.

2.0.20　Automatic Gas Shielded-Arc Welder

It's a welder which can automatically perform the gas shielded arc welding except its parameter setup and start/stop.