Abstract: To solve the issue concerning cost effectiveness of rolling Ф473.08 mm×11.05 mm ultra-limit casing, it is proposed to design and develop the 488 mm pass.And the following actions are involved.Tamper of the cylindrical mandrel bar is modified for tackling the problem that the extractor can't get the mandrel off the shell due to its poor reduction rate;the deformation amounts of the piercing mill and the mandrel mill proper are redistributed, and the shell clearance adjusted in order to meet the quality assurance requirements for the product.The Ф473.08 mm×11.05 mm ultra-limit casing as designed and developed has been put into massive production, which proves that the Ф460 mm 3-roll PQF mill is capable of producing light-wall pipes with large D/S.