HOLLOW MEMBER AND METHOD FOR MANUFACTURING HOLLOW MEMBER

A hollow member formed in a tube-like shape and subjected to a torsional force acting about the center axis of the hollow member is characterized in that a part of the peripheral wall of the hollow member is heated to increase the hardness of the outer side of the peripheral wall to a level higher than the hardness of the outer side of the peripheral wall before the part of the peripheral wall is heated and higher than the hardness of the inner side of the peripheral wall, and in that the hollow member is subjected to partial heat treatment which reduces residual stress in the inner side of the peripheral wall. Un miembro hueco tubular al cual se aplica torsión alrededor de una línea central, se caracteriza porque realizar un tratamiento térmico parcial en parte de una pared periférica del miembro hueco para hacer la dureza de una porción exterior de la pared periférica mayor que la dureza antes de calentar y mayor que la dureza de una porción exterior de la pared periférica, y reducir una tensión residual de la porción interior de la pared periférica.