System and method for connecting metal workpieces

A method of forming an assembly in which an extension element partially defined by an extension element axis thereof is connected with a body having a flat surface defining a surface plane with at least one aperture therein, said at least one aperture being partially defined by a central axis thereof and an aperture perimeter region on the flat surface, the method comprising the steps of:

• (a) providing an intermediate element metallically bondable with each of the body and the extension element respectively, the intermediate element being partially defined by an intermediate element axis, the intermediate element extending between first and second ends thereof, each of the first and second ends respectively defining first and second planes;
• (b) positioning the intermediate element relative to the aperture perimeter region to define a first gap between the first end of the intermediate element and the aperture perimeter region, to locate the first plane and the surface plane parallel to each other and to align the intermediate element axis with the central axis;
• (c) positioning the extension element relative to the intermediate element to define a second gap between an inner end of the extension element and the second end of the intermediate element, the inner end defining an extension element inner end plane, to locate the extension element inner end plane and the second plane parallel to each other and to align the extension element axis with the intermediate element axis;
• (d) providing at least one first heating element and at least one second heating element;
• (e) locating said at least one first heating element and said at least one second heating element in the first and second gaps respectively;
• (f) providing a non-oxidizing atmosphere in defined volumes around each of the first gap and the second gap respectively;
• (g) energizing said at least one first heating element to heat the aperture perimeter region and the first end of the intermediate element to a hot working temperature in the non-oxidizing atmosphere, and energizing said at least one second heating element to heat the second end of the intermediate element and the extension element inner end to the hot working temperature in the non-oxidizing atmosphere, to provide respective hot portions of each of the body and the intermediate element at the first end thereof, and respective hot portions of each of the extension element and the intermediate element at the second end thereof, each said hot portion being at the hot working temperature;
• (h) removing said at least one first heating element and said at least one second heating element from the first and second gaps respectively;
• (i) rotating the intermediate element about the intermediate element axis;
• (j) while the respective hot portions of the intermediate element at the first end thereof and the body are at the hot working temperature, and while the intermediate element rotates about the intermediate element axis, urging the first end of the intermediate element against the aperture perimeter region, for plastic deformation of the intermediate element at the first end, and for plastic deformation of the body at the aperture perimeter region, to bond the intermediate element and the body with each other;
• (k) rotating the extension element about the extension element axis;
• and
• (l) while the respective hot portions of the intermediate element at the second end thereof and the extension element are at the hot working temperature, and while the extension element rotates about the extension element axis, urging the extension element inner end against the second end of the intermediate element, for plastic deformation of the intermediate element at its second end, and for plastic deformation of the extension element at the extension element inner end, to bond the intermediate element and the extension element with each other.

A method of forming an assembly, the method comprising:

• (a) providing a first tube partially defined by a first tube axis, the first tube having a first tube outer diameter at a first tube open end thereof, the first tube comprising a first tube channel therein defined by a first tube inner diameter;
• (b) providing an extension tube partially defined by an extension tube axis, the extension tube having an extension tube outer diameter, the extension tube comprising an extension tube channel therein defined by an extension tube inner diameter;
• (c) providing an intermediate tube metallically bondable with each of the first tube and the extension tube respectively, the intermediate tube being partially defined by an intermediate tube axis, the intermediate tube extending between first and second open ends thereof, the intermediate tube having a first outer diameter at the first open end thereof that is equal to the stationary tube outer diameter, the intermediate tube comprising an intermediate tube channel therein extending between the first and second open ends, the intermediate tube channel having a first inner diameter at the first open end that is equal to the first tube inner diameter, and the intermediate tube channel having a second inner diameter at the second open end that is equal to the extension tube inner diameter;
• (d) positioning the intermediate tube relative to the first tube to define a first gap between the first open end of the intermediate tube and the first tube open end, and to align the intermediate tube axis with the stationary tube axis:
• (e) positioning the extension tube relative to the intermediate tube to define a second gap between an inner end of the extension tube and the second open end of the intermediate tube, and to align the extension tube axis with the intermediate tube axis, the intermediate tube having a second outer diameter at the second open end that is equal to the extension tube outer diameter:
• (f) providing at least one first heating element and at least one second heating element:
• (g) locating said at least one first heating element and said at least one second heating element in the first and second gaps respectively;
• (h) providing a non-oxidizing atmosphere in defined volumes around each of the first gap and the second gap respectively;
• (i) energizing said at least one first heating element to heat the first tube open end and the first open end of the intermediate tube to a first hot working temperature in the non-oxidizing atmosphere, and energizing said at least one second heating element to heat the second open end of the intermediate tube and the extension tube inner end to a second hot working temperature in the non-oxidizing atmosphere, to provide respective first, second, third, and fourth hot portions of each of the first tube, the intermediate tube at the first open end thereof, the intermediate tube at the second open end thereof, and the extension tube respectively, said first and second hot portions being at the first hot working temperature, and said third and fourth hot portions being at the second hot working temperature;
• (j) removing said at least one first heating element and said at least one second heating element from the first and second gaps respectively;
• (k) rotating the intermediate tube about the intermediate tube axis;
• (l) while the first hot portion and the second hot portion are at the first hot working temperature, and while the intermediate tube rotates about the intermediate tube axis, urging the first open end of the intermediate tube against the first tube open end, for bonding the intermediate tube and the first tube with each other;
• (m) rotating the extension tube about the extension tube axis;
• and
• (n) while the third hot portion and the fourth hot portion are at the second hot working temperature, and while the extension tube rotates about the extension tube axis, urging the extension tube inner end against the second open end of the intermediate tube, for bonding the extension tube and the intermediate tube with each other to form the assembly.