Application of Six Sigma to Improving Yield of Heavy-walled HFW Pipe Production

The root cause that restrains yield of the Φ610 mm HFW pipe production line is identified by means of the Six Sigma Method containing such tools as Plato, Student's T test, non-parameter test, and variance analysis. Accordingly, corrective actions are determined and taken to optimize forming and welding processes, and modify inner burr cutter bar. As a result, the yield of the said production line has been increased by 14.2%, and the yield Sigma level has been also enhanced from the original 0.66 to 1.23.