PURPOSE: To provide a steel pipe column prepared through cold processing which excels in the plastic deformation ability for a bending load by subjecting it to a heat treatment locally as covering the part for a specific distance from one of the column ends, maximally till the part a specific times as large as the column width from its one end.
CONSTITUTION: The bending load is distributed so that it maximizes in the joint part with the leg of a steel pipe column prepared through cold processing and decreases as going apart from the joint part. The steel pipe column is subjected to a heat treatment locally as covering the part for a distance of 100mm from one of the column ends, maximally till the part three times as large as the column width from one end. Heat treatment is made at 500-980°C, followed by cooling. This yields steel pipe column which exerts an excellent plastic deformation ability even in case a bending load is applied.
OKAMOTO HARUHITO
ITO SHIGEKI
KATAYAMA TADATERU
