Pipes are manufactured in complete compliance with the Japanese Industrial Standards (JIS). The raw material, stainless steel sheet, is rolled into a pipe with rollers. Then, the pipes go through quality TIG welding with argon gas shielding, followed by fine grinding and the subsequent annealing solution heat treatment and straightening. Non-destructive tests are performed in real time on line through the eddy current inspection instrument to prevent against release of stainless steel pipes with welding defects. After the inspection is completed, pipes are cut to meet the 4-meter specification requirement for the Japanese market. The first step of the pipe manufacturing process is completed for now.
Cut stainless steel pipes go through pickling as part of surface treatment, are rinsed in clean water at high pressure, and then let dry to become clean and pure. To ensure that products are perfect without defects, it is required to perform the air tightness test on the pipes again; pressurized air is instilled into the pipes and the pipes are inspected for air bubbles indicating presence of undesirable holes. After they complete the test and are qualified, they go through the full-circle eddy current inspection test that helps confirm absence of defects. Then, the make and specification label is printed on the finished product. All stainless steel pipes are manufactured having gone through two eddy current inspections and one air tightness test to ensure perfection of stainless steel products released from the factory before they enter the packaging and shipping stage.