The production process of welded stainless steel pipe
The main industry is the nominal pipe diameter of more than DN700 in the pipeline. Slotted pipe not only includes the straight pipe, and comprises a spiral weld pipe. The main specifications and production of welded stainless steel pipe with nominal diameter 700mm multiplied by the thickness of 10mm (denoted as 711x10), nominal pipe diameter 800mm multiplied by the thickness of 12mm (denoted as 813x12), multiplied by the nominal pipe diameter 900mm and 14mm thick steel plate (denoted as 914x14), multiplied by the nominal diameter 1000mm 18mm thick (expressed as 1016 x18) and other product specifications.
In the production of welded stainless steel pipe, the first step is to identify the material of stainless steel plate. Determine the stainless steel pipe material and the perimeter of the steel pipe, and purchase the corresponding material, width and steel plate circumference of the same grade stainless steel plate. Enter the production site after surface inspection of steel plate according to the forming of the steel plate, steel plate or oxide scale is determined, no pits or less cellular, and less area of on-site grinding or sandblasting. Nondestructive testing followed by the end of the plate, here is generally used in penetrant inspection, is the first to end with a cleaning agent for cleaning and dry, then spray stains, wait a few minutes later, wipe the stains, spray on the imaging agent, wait a few minutes after the end of observation is there red lines to confirm whether there are defects in stainless steel plate. The steel plate is then double or single sided ultrasonic testing, and the ultrasonic wave is used to judge whether the steel plate is defective or not.
The steel plate after the test is finished, the second step is the first rolling, rolling machine press select the corresponding arc, and then put into the steel plate rolling machine under rolling, the stainless steel plate rolled into a cylindrical slowly. Followed by third steps of pre welding, pre welding, if the machine is submerged arc welding, but also must be welded at both ends of the pipe arc starting plate, and then carry out flower welding.
The welding steps are divided into priming and filling and capping. After the completion of welding work, is to do NDT, for ray by RT ray of steel pipe welding, welding internal confirmation does not appear root not melting, unweld, welding slag, stratification, large quantities of gas welding defects. Then the pipeline pressure test process, in accordance with the design pressure of 1.5 times the pipe pressure test, to ensure that the pipeline under the pressure intensity, the pipeline without structural deformation, no leakage, the pressure to maintain stability. Finally, the heat treatment of the steel pipe weld, after a period of time so that the temperature between the weld to maintain a heat treatment temperature for a few minutes to half an hour, and then slowly cooling, the production of steel pipe is basically completed. The remaining tasks are the identification, spraying and corrosion protection of the pipeline. The marking contents include the name of the factory, the specification and model of the pipe, the material of the pipeline, the batch number of the pipe and the grade of anticorrosion of the pipeline.
After a series of work, a plain steel plate is transformed into a pipe that can transport gases, liquids and other mediums. In order to ensure the quality of the pipeline, before leaving the factory, it is necessary to review the pipeline material, usually the same batch of pipes for spot checks, inspection of spectrum and hardness. Next, review the size of the pipe and sign on the production list to confirm the completion.
Source: China Stainless Steel Pipe Manufacturer - Yaang Pipe Industry Co., Limited (www.yaang.com)