The raw material is the most important, because the quality control which usually begins with the purchase of raw material is during the all steps of production process. We should choose the best and most proper and efficient raw material, for example, high-quality, continuous-cast, fully killed, control-rolled, fine-grain, low-carbon steel. In order to satisfy the demands, a number of dependable, reputable suppliers are necessary. When the skelp inventory is received and entered into a computer database, it is treated as cross-check against supplier documentation.
Step 2, loading. According to order requirements, it is necessary to verify the coils against database information and load the coils into the mill with a dual cone uncoiled. Step 3, edging. The scalp edges should be sheared or milled to meet the requirements of the pre-specified widths. In addition, in order to thread into the mill, the lead end of each coil should be squared. Then then API 5l steel pipe products can be formed. A modern, edge-forming system for controlled skelp shaping is necessary. The technology used for forming is often updated, and there is technology that can provide the latest innovations in forming, for example, pre-form stands, cage and internal forming, and fin pass stands to allow.The next step is welding. The operators should use a high-frequency welder to examine and adjust alignment, temperature, speed and trim removal. Then we should weld seam annealing. The minimum temperature provided by seam annealers is 1600' F. An optical pyrometer, which is connected to the mill computer system, is useful for measurement and record. The next is sizing, which is also called as cutting. To meet the specifications and additional standards required by customers, there are three sizing stands and one straightening stand that can be used. Cut the pipe to length with a rotary cutoff, and the mill computer should assign the identification to each piece when cutting.
Then inspect each pipe to assure compliance with specified requirements, and those tests include a hydrostatic test, an ultrasonic weld inspection, an end finish check, wall thickness verification, a straightness evaluation, and an inside and outside surface visual inspection.
