Tubulars - Tool Joints

Tool Joints


Tool joints are short sections of pipe that are attached to the tubing portion
of drill pipe by means of using a flash welding process. The internally
threaded tool joint is called a “box”, while the externally threaded tool joint
if the “pin”.
API specifications also apply to tool joints:
• Minimum Yield Strength = 120,000 psi
• Minimum Tensile Strength = 140,000 psi
Because tool joints are added to drillpipe, the weight of given to pipe in
many tables is the “nominal weight”. The exact weight will require adding
the weight of the tool joints to the tubing portion. Since two joints do not
weigh the same, it is difficult to determine the weight of a joint of drillpipe
and so an “approximate weight” is used in many calculations.
The tool joints on drill pipe may contain internal and/or external upsets. An
upset is a decrease in the ID and/or an increase in the OD of the pipe which
is used to strengthen the weld between the pipe and the tool joint. It is
important to note that under tension, the tool joint is stronger than the
tubular.