PREVENTION OF COCKLE IN RIMMED STEEL PLATE BY TENSION LEVELER

摘要

PURPOSE:To obtain good quality steel plate by preventing the occurrence of cockle by eliminating the difference in plastic elongation between core portion and rim portion by the use of a specific form of tension roller when the flatness of rimmed steel is corrected by tension leveler. CONSTITUTION:Based on an equation and experimental results (separately mentioned), the difference in diameter, DELTAd, between both contacting ends of the central straight portion 3 of the tension roller 1 provided on a tension leveler and the rimmed steel plate 2 is set up to DELTAd=KDELTAdelta/E [K is constant (1500 to 4500), DELTAdelta is difference in yield stress between the central part and the both ends of steel plate, and E is Young's modulus], and also a tension roll 1 with the taper of the relationship B/2=L1=B-Be [B is the whole width of steel plate and Be is the total rim layer width of the both ends of steel plate] is used for the straight portion L1 of the roller central part. Thus, a difference in diameter is made between the core portion 4 and the rim portion 5 and thus their plastic elongations become equal, preventing the occurrence of cockle. Thus, good quality steel plate can be obtained.