METHOD FOR PRODUCING SEAMLESS PIPE

• Main Authors: SHIMODA, KAZUHIRO, YAMAKAWA, TOMIO, INAGE, TAKATERU
• Format: Patent
• Language: English; French; German
• Published: 02.10.2013
• Subjects: MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVINGMATERIAL; PERFORMING OPERATIONS; PUNCHING METAL; ROLLING OF METAL; TRANSPORTING

Disclosed is a method for producing a seamless pipe by using a piercing mill which pierces and rolls a round billet heated to 1300°C or lower, wherein the piercing mill is composed of a pair of skew rolls disposed to face each other across a pass line, a pair of guide devices disposed to face each other across the pass line, and a plug disposed along the pass line, between the pair of the skew rolls and also between the pair of the guide devices, wherein the piercing-rolling is performed under the conditions satisfying the following formulas (1) to (3) to prevent wrinkle flaws of the seamless pipe: - 1.0 < ”¸ ”¸ = ¸ p - ¸ r - 0.37 × ”¸ + 1.47 ‰¤ R n ‰¤ 0.37 × ”¸ + 2.67 wherein the meanings of the individual symbols in the above-described formulas are as follows: ¸ r : The half angle (°) between the pass line and the main roll face in the condition of the feed angle of the main rolls being zero ¸ p : The half angle (°) between the pass line and the reeling section of the plug R n : The number of times of the reeling of the plug