HOLLOW DRILLING STEEL ROD AND METHOD OF MANUFACTURING THE SAME

摘要

The present invention relates to a hollow drilling steel rod including a stem portion and a thread portion positioned at an end portion in an axial direction with respect to the stem portion, the hollow drilling steel rod being constituted of a steel having a specific composition described in the present specification, in which the thread portion includes a thread having been subjected to a high frequency quenching, and the thread portion and the stem portion separate from each other have been joined by a friction welding.