There are numerous factors affecting the appearance quality of the welds of carbon steel plate spiral pipes. Summarizing years of production experience of spiral steel pipes, these factors mainly include a combination of aspects such as welding process parameters, wire position and shape parameters, flux flow rate, flux process performance, and forming seams. The influence of welding process parameters mainly includes two aspects:
(1) Welding current. According to the production characteristics of spiral steel pipes, a relatively small welding current is usually used for internal welding, while a larger one is used for external welding. However, under the condition of a large welding current, the agitation effect of the molten pool intensifies, and the melting amount of the welding wire also increases accordingly. As a result, the weld reinforcement becomes higher, the weld formation deteriorates, and the edge transition is poor.
(2) Welding voltage. Since the welding arc is conical in shape, the magnitude of the welding voltage directly affects the length of the arc. Therefore, as the welding voltage increases, the arc length increases, the moving range of the arc spot expands, the molten pool widens, and a wider weld formation is obtained. If the welding is carried out in a horizontal position, only the width of the weld will change, without affecting the edge transition of the weld. However, the external welding of spiral welded pipes is carried out on an inclined plane, and the molten weld metal will flow laterally under the action of gravity. Thus, it can be seen that the larger the welding voltage, the wider the molten pool, and the more serious the tendency of the weld metal to flow laterally, ultimately leading to the flow deviation of the weld metal.

We have the capabilities to produce high - quality transmission steel pipes in terms of both pipe - making and inspection equipment. Before the trial production of each batch of steel pipes, we conduct strict process appraisals in accordance with standards. Based on the appraisal results, we determine the technical parameters for steel pipe production through optimization to ensure the production of high - quality products. Then, according to the company - formulated process flow, we break it down to various production and inspection positions, and set out the process parameters and operation methods for each position to guide production. During the production process of steel pipes, we strictly supervise and inspect the implementation of process discipline. For problems found, we promptly take corrective and preventive measures, and conduct assessments in accordance with the company's quality assessment system to ensure strict compliance with process discipline and guarantee product quality. Our company has established a dedicated inspection agency responsible for the quality inspection of the entire process from the incoming raw materials to the warehousing of products. The steel pipes produced by our Chicheng Company undergo 100% internal weld inspection, 100% X - ray inspection (with no blind area at the pipe ends), 100% hydrostatic pressure test (the hydrostatic pressure test adopts end - face sealing, minimizing the blind area at the pipe ends), and 100% appearance inspection (including the internal and external welds and the surface of the base metal). Our company's laboratory is equipped with advanced inspection equipment, such as imported Spectro direct - reading spectrometers and digital display tensile testing machines, which can conduct accurate chemical analysis and mechanical property tests on products. The on - line automatic ultrasonic flaw - detection device and X - ray industrial flaw - detection device can conduct 100% non - destructive testing on products. The hydrostatic pressure test automatic recorder can ensure that each steel pipe is pressure - tested and pressure - maintained according to the specified pressure and time.

Our welded pipe production is dedicated to manufacturing various types of circumferential - seam, longitudinal - circumferential welded pipes and steel pressure pipes. We have also modified the traditional welded - pipe equipment of the same specifications and models, enabling a 30% improvement in various parameters of the welded - pipe equipment. This fills the production gap that the original traditional rolling equipment could not cover. We can produce steel pipes with a diameter of over 400 mm and a wall thickness of 8 - 100 mm. The main materials include Q235A, Q345B, 20#, 45#, 35CrMo, 42CrMo, 16Mn, 16MnR, and general cold - rolled plates can also be used for welded - pipe production, etc. The product execution standards are: GB/T50205 - 2001, GB/T3092 - 2001, etc. Welded pipes are widely used in projects such as oil, chemical, and natural gas transportation, piling, and urban water supply, heating, and gas supply.

Chinese name: Welded tube
English name: welded tube, welded pipe
Definition: A type of pipe formed by curling a strip into a tube with specified shape and size, and then welding the seam with an appropriate welding method.
Applied discipline: Materials Science and Technology (primary discipline); Fundamentals of Materials Science and Technology (secondary discipline); Materials Synthesis, Preparation and Processing (tertiary discipline); Plastic Processing Technology (quaternary discipline)

Our welded - pipe production is dedicated to manufacturing various types of circumferential - seam, longitudinal - circumferential welded pipes and steel pressure pipes. We have also modified the traditional welded - pipe equipment of the same specifications and models, enabling a 30% improvement in various parameters of the welded - pipe equipment. This fills the production gap that the original traditional rolling equipment could not cover. We can produce steel pipes with a diameter of over 400 mm and a wall thickness of 8 - 100 mm. The main materials include Q235A, Q345B, 20#, 45#, 35CrMo, 42CrMo, 16Mn, 16MnR, and general cold - rolled plates can also be used for welded - pipe production, etc.