Method for making upset ends on metal pipe and resulting product

A method of forming a finished internal upset on a uniform thickness end portion of metal pipe in a single heating of the metal pipe;

• said method comprising the following steps:
• first heating the metal pipe to a temperature between 1750F. and 2600F.;
• then radially expanding externally said end portion of said metal pipe in a first forging step to increase the wall thickness externally in a radial direction at least around twenty (20)%) percent and to form an outer transition section of varying diameters between the increased wall thickness and said initial wall thickness for forming an external upset;
• next radially expanding externally said end portion of said metal pipe in a second forging step without reheating of said metal pipe to further increase the wall thickness externally in a radial direction at least around twenty (20%) percent;
• and
• then radially contracting said external upset in a pair of forging steps performed without reheating of said metal pipe for forming an internal upset having an end section of an increased wall thickness and an inner transition section between the increased wall thickness of said end section and said initial wall thickness.

A method of forming a finished internal upset on an end portion of metal pipe having an initial uniform wall thickness comprising the following steps:

• radially expanding said end portion of said metal pipe in one forging step to increase the wall thickness in a radial direction and to form an outer curvature on an outer transition section between the increased wall thickness and said initial wall thickness for forming an external upset;
• and
• radially contracting said external upset in another forging step for forming an internal upset having an end section of an increased wall thickness and an inner transition section having an inner concave curvature between the increased wall thickness of said end section and said initial wall thickness, said inner curvature corresponding generally to said outer curvature of said external upset;
• said step of radially contracting said external upset including the forming of a continuous inner concave curvature on said inner transition section from a radius having a length which is at least three times the internal diameter of said metal pipe.

A method of forming a finished internal upset on an end portion of metal pipe having an initial uniform wall thickness comprising the following steps:

• radially expanding said end portion of said metal pipe in one forging step to increase the wall thickness in a radial direction and to form an outer curvature on an outer transition section between the increased wall thickness and said initial wall thickness for forming an external upset;
• and
• radially contracting said external upset in another forging step for forming an internal upset having an end section of an increased wall thickness and an inner transition section having an inner concave curvature between the increased wall thickness of said end section and said initial wall thickness, said inner curvature corresponding generally to said outer concave curvature of said external upset;
• said step of radially contracting said external upset including the forming of an external conical taper on the outer periphery of said pipe.

A method of forming a finished internal upset on an end portion of metal pipe having an initial uniform wall thickness comprising the following steps:

• radially expanding said end portion of said metal pipe in one forging step to increase the wall thickness in a radial direction and to form an outer concave curvature on an outer transition section between the increased wall thickness and said initial wall thickness for forming an external upset;
• and
• radially contracting said external upset in another forging step for forming an internal upset having an end section of an increased wall thickness and an inner transition section having an inner concave curvature between the increased wall thickness of said end section and said initial wall thickness, said inner curvature corresponding generally to said outer concave curvature of said external upset;
• said step of radially expanding the end portion of said metal pipe including a die having an inner peripheral surface defining an inner convex curvature conforming to said outer concave curvature on said outer transition section, and a mandrel having a projection fitting within said pipe and maintaining a continuous inner peripheral surface of a uniform diameter on said metal pipe.

A method of forming an internal upset end portion on metal pipe comprising the following steps:

• providing metal pipe having a uniform predetermined wall thickness;
• determining from the desired finished internal upset the volume of metal material in a predetermined number of longitudinal elements along the length of the finished internal upset including an internal upset transition section having an inner peripheral surface formed of a continuous curvature;
• providing a first die for one forging step having an inner peripheral surface of dimensions for forming an external upset on said metal pipe having longitudinal elements and an external profile along its length corresponding to longitudinal elements and an internal profile for the finished internal upset with corresponding elements having a similar volume of metal material;
• forging in said one forging step by inserting a first mandrel within said first die for squeezing radially outwardly the pipe to form said external upset with said longitudinal elements having substantially the same material volumes as corresponding longitudinal elements in the finished internal upset, the inner peripheral surface of said drill pipe being unchanged in said one forging step;
• providing another die and mandrel of dimensions to form in another forging step said internal upset including an internal upset transition section having an inner peripheral surface formed of a continuous curvature;
• and
• forging said internal upset in said another forging step by inserting said another mandrel within said another die for squeezing radially inwardly said external upset formed in said one forging step with the material volume for each of said longitudinal elements in said external upset being transferred to a corresponding longitudinal element in said internal upset to form the inner peripheral surface of said internal upset transition section with a continuous curvature;
• said step of forging said internal upset in said another forging step including the forming of said continuous curvature on said transition section from a single radius having a length at least three times the internal diameter of said pipe to define a continuous inner concave curvature.

A method of forming a finished internal upset on a uniform thickness end portion of metal pipe in a single heating of the metal pipe;

• said method comprising the following steps:
• first heating the metal pipe to a temperature between 1750 F. and 2600 F.;
• then radially expanding externally said end portion of said metal pipe in a first forging step to increase the wall thickness externally in a radial direction at least around twenty (20)%) percent and to form an outer transition section of varying diameters between the increased wall thickness and said initial wall thickness for forming an external upset;
• next radially expanding externally said end portion of said metal pipe in a second forging step without reheating of said metal pipe to further increase the wall thickness externally in a radial direction at least around twenty (20%) percent;
• then radially contracting said external upset in a pair of forging steps without reheating of said metal pipe for forming an internal upset having an end section of an increased wall thickness and an inner transition section between the increased wall thickness of said end section and said initial wall thickness;
• providing a tube upsetting machine having at least three pipe cavities with each pipe cavity having a separate set of dies and mandrels;
• performing each of said forging steps within a separate cavity of said tube upsetting machine;
• and
• transferring said pipe between said cavities for performing said forging steps in a minimum of time less than around two (2) minutes.