Distortion Correcting of Welded Thin Plate Structures (Part IV)

Effects of different operating conditions on distortion correcting

Abstract

Based on previous fundamental investigations the authors studied on the effects of various operating conditions.
Steel plates, 200×200×2.3mm, were heated and cooled rapidly at the center by oxy-acethylene flame under difierent conditions with heating time varied 2, 4, 6 and 9 sac; the radius of heated zone, 5, 10, 15 and 20mm. Radial shrinkages were then measured; They agreed with theoretical calculations made on the the theory advanced in Part I. In these experiments the maximum value of radial shrinkage increased as the heating temperature or time was raised : but from the viewpoint of the property change of the plate the temperature proved most adequate at about 600-650°C, while the most adequate heating time was 2-3 sec with No. 500 torch applied. The most desirable diameter of heated zone was 22-24mm, because the maximum radical shrinkage was then greatest. The preferrable pitch of heated zone is about 2.5 times its diameter, i. e., 50-75mm from the viewpoint of the shape of hole drilled on cover plate.