Patent ID: 9561537
Date: 2017-02-07
CPC Classifications: B21D,B21J,B21K,E21B

Claim:
1. A method of forming a section of trenchless horizontal directional drilling drill pipe as a single piece of forged pipe having internally and externally upset pipe ends, the method comprising the steps of: providing a single section of green pipe having opposing pipe ends and heating at least a selected one of the pipe ends to a predetermined forging temperature; upsetting and pressing the selected pipe end to form an external upset portion having an outer taper; pressing the external upset portion with an internal upset die so as to displace the outer taper and form an internal upset portion having an inner taper; internally upset forging the upset portion with an internal upset die to produce a finished part; wherein the pressing is accomplished by applying hydraulic pressure using a hydraulic forging press to form a selected upset pipe end which has an upset external diameter and an upset internal diameter, a portion of the upset internal diameter being subsequently threaded to form the threaded internal bore, the ratio of the external diameter to the internal diameter in the region of the threaded internal bore being about 3.5 or greater; wherein the selected upset pipe end has a first internal diameter of generally uniform diameter, a second flared internal diameter and an outer upset length, and wherein the length of the first internal diameter is greater than 30% of the length of the outer upset length; and repeating the above method steps onto another end of said opposing pipe ends, thereby forming said upset pipe ends.