Effect of the Groove Shape of Ultra Thick Box-Column with Center Segregation under High Heat Input for Corner Welding

J. Ocean Eng. Technol. 2002;16(2):72-79.

중심 편석층이 있는 극후판 박스-칼럼의 대입열 코너이음 용접시 그루브 형상의 영향

최원규,이종봉,권영두,구남서

포항제철 기술연구소,포항제철 기술연구소,경북대학교 기계공학부,경북대학교 기계공학부

Keywords: Center Segregation, Temperature Distribution, Phase Distribution, Groove Type, Groove Angle

핵심용어: 중심편석대, HAZ 열영향부, 온도분포, 상분포, 그루브 형상, 그루브 각도

Abstract

In this study, time-dependent distributions of temperature and stresses, in the box-column welded from ultra thick plates with center segregation, has been analyzed by the commercial finite element package SYSWELD+, for several types and angles of groove. The major points of investigation are the optimum type and angle of groove that minimize weld stress specially at the center segregation, as well as temperature distribution, residual stresses and changes in the mechanical properties. The results can be summarized as follows; 1) Generally the thermal cycle at the root of groove exhibits relatively rapid cooling pattern, however, most of the other part weldment have a slow cooling pattern in all groove types. 2) Most of the micro-structures of weldment are composed of ferrite and pearlite, meanwhile we could find martensite and bainite locally a the root of the groove. 3) Optimum groove type for high heat input welding of box-column corner is a double groove type, and the optimum angle for the groove is 30~$45^{circ}$ that minimize deformation and weld stress at the center segregation.