Forge welding with induction coil heating

Claim 1

A method of forge welding together a first metal part at a surface thereof to a second metal part along a correspondingly shaped surface thereof at an elevated, forge welding temperature, each said surface extending around and being spaced from a predetermined point to form a closed, electrically conductive path having a pair of edges, one at one side of the path and the other at the other side of said path, the spacing between said edges on one said surface being substantially equal to the spacing between said edges on the other said surface and said surface of said first metal part being spaced from said point by substantially the same distance as said surface of said second metal part, at least one of said parts having metal extending from at least one edge of its said path in a direction away from said path, said direction being parallel to said surface of said last-mentioned one part, said method comprising placing said surface of one said part adjacent and facing said surface of the other said part to thereby provide a pair of facing surfaces; heating the metal at said facing surfaces to said forge welding temperature by inducing an alternating current in the metal at said facing surfaces with an induction coil closely adjacent said facing surfaces, said coil having a conductor extending at least partly around said point and having a shape in the circumferential direction around said point corresponding substantially to the shape in said circumferential direction of at least one said surface, the dimension of said conductor in said circumferential direction being the length thereof, the path of said current at the surface of said metal which is nearest said conductor having a predetermined width in a first direction substantially at right angles to said length dimension of said conductor and said conductor having a dimension in said first direction approximately equal to the desired dimension of said width of said path of the current flow in the metal to be heated to confine said current to a relatively narrow path in said lastmentioned metal, said current having a reference depth in said metal at said forge welding temperature at least equal to onehalf the dimension, in a second direction substantially perpendicular to said first direction, of the metal intermediate said conductor and said edges of said facing surfaces which are farthest from said conductor; terminating said current when the metal at said facing surfaces reaches said forge welding temperature and while substantially all of said metal extending away from said edge of said surface of said first-mentioned one part is still at a lower temperature, said current being of a magnitude sufficient to so heat the metal at said facing surfaces to said forge welding temperature before a significant portion of said metal extending away from said last-mentioned edge reaChes said forge welding temperature and being of a magnitude less than that which will cause the metal nearest said conductor to melt significantly during the time of flow of said current; and pressing said parts together at said surfaces with forge welding pressure at least when said metal at said facing surfaces has reached said forge welding temperature.

Claim 2

A method of forge welding together a first metal part at a surface thereof to a second metal part along a correspondingly shaped surface thereof at an elevated, forge welding temperature, each said surface extending around and being spaced from a predetermined point to form a closed, electrically conductive path having a pair of edges, one at one side of the path and the other at the other side of said path, the spacing between said edges on one said surface being substantially equal to the spacing between said edges on the other said surface and said surface of said first metal part being spaced from said point by substantially the same distance as said surface of said second metal part, at least one of said parts having metal extending from at least one edge of its said path in a direction away from said path, said direction being parallel to said surface of said last-mentioned one part, said method comprising placing said surface of one said part adjacent and facing said surface of the other said part to thereby provide a pair of facing surfaces; heating the metal at said facing surfaces to said forge welding temperature by inducing an alternating current in the metal at said facing surfaces with an induction coil closely adjacent said facing surfaces, said coil having a conductor extending at least partly around said point and having a shape in the circumferential direction around said point corresponding substantially to the shape in said circumferential direction of at least one said surface, the dimension of said conductor in said circumferential direction being the length thereof, the path of said current at the surface of said metal which is nearest said conductor having a predetermined width in a first direction substantially at right angles to said length dimension of said conductor and said conductor having a dimension in said first direction approximately equal to the desired dimension of said width of said path of the current flow in the metal to be heated to confine said current to a relatively narrow path in said lastmentioned metal, said current having a reference depth in said metal at said forge welding temperature at least equal to onehalf the dimension, in a second direction substantially perpendicular to said first direction, of the metal intermediate said conductor and said edges of said facing surfaces which are farthest from said conductor; terminating said current when the metal at said facing surfaces reaches said forge welding temperature and while substantially all of said metal extending away from said edge of said surface of said first-mentioned one part is still at a lower temperature, said current being of a magnitude sufficient to so heat the metal at said facing surfaces to said forge welding temperature before a significant portion of said metal extending away from said last-mentioned edge reaChes said forge welding temperature and being of a magnitude less than that which will cause the metal nearest said conductor to melt significantly during the time of flow of said current; and pressing said parts together at said surfaces with forge welding pressure at least when said metal at said facing surfaces has reached said forge welding temperature.

Claim 11

A method of forge welding together a pair of dissimilar metal parts, one part having a surface with generally circular inner and outer edges and the other part having a surface corresponding in shape and size to said surface of said one part and having metal extending in a radial direction with respect to its surface and from an edge thereof, said method comprising placing said surface of said one part in contact with said surface of said other part to thereby provide a pair of contacting and facing surfaces; heating said surfaces and the metal immediately adjacent and extending perpendicular thereto to an elevated, forge welding temperature by including an alternating current in the metal of said parts At and adjacent said surfaces with a generally circular induction coil closely adjacent said surfaces, concentric therewith and spaced radially therefrom, said coil having a dimension in a direction perpendicular to the plane of meeting of said surfaces approximately equal to the desired dimension in said last-mentioned direction of the current flow in the metal to be heated to confine said current to a relatively narrow path in said last-mentioned metal and said current having a reference depth in said metal at said forge welding temperature at least substantially equal to the dimension of said surfaces in the direction parallel to said plane; terminating said current when said surfaces and the metal immediately adjacent thereto reach said forge welding temperature and while substantially all of said metal extending radially of said surface of said other part is still at a lower temperature, said current being of a magnitude sufficient to so heat said surfaces and said metal immediately adjacent thereto to said forge welding temperature before a significant portion of said metal extending radially reaches said forge welding temperature and being of a magnitude less than that which will cause the metal nearest said coil to melt significantly during the time of flow of said current; and pressing said parts together at said surfaces with forge welding pressure at least when said surfaces and said metal immediately adjacent thereto have reached said forge welding temperature.

Claim 12

A method of forge welding together a pair of dissimilar metal parts, one part having a surface with generally circular inner and outer edges and the other part having a surface corresponding in shape and size to said surface of said one part and having metal extending in a radial direction with respect to its surface and from an edge thereof, said method comprising placing said surface of said one part in contact with said surface of said other part to thereby provide a pair of contacting and facing surfaces; heating said surfaces and the metal immediately adjacent and extending perpendicular thereto to an elevated, forge welding temperature by including an alternating current in the metal of said parts At and adjacent said surfaces with a generally circular induction coil closely adjacent said surfaces, concentric therewith and spaced radially therefrom, said coil having a dimension in a direction perpendicular to the plane of meeting of said surfaces approximately equal to the desired dimension in said last-mentioned direction of the current flow in the metal to be heated to confine said current to a relatively narrow path in said last-mentioned metal and said current having a reference depth in said metal at said forge welding temperature at least substantially equal to the dimension of said surfaces in the direction parallel to said plane; terminating said current when said surfaces and the metal immediately adjacent thereto reach said forge welding temperature and while substantially all of said metal extending radially of said surface of said other part is still at a lower temperature, said current being of a magnitude sufficient to so heat said surfaces and said metal immediately adjacent thereto to said forge welding temperature before a significant portion of said metal extending radially reaches said forge welding temperature and being of a magnitude less than that which will cause the metal nearest said coil to melt significantly during the time of flow of said current; and pressing said parts together at said surfaces with forge welding pressure at least when said surfaces and said metal immediately adjacent thereto have reached said forge welding temperature.

Claim 15

A method of forge welding together a pair of dissimilar metal parts, one part having a surface in the shape of a generally circular band and the other part having a surface corresponding in shape to said surface of said one part but of a different diameter and having metal extending in an axial direction with respect to its surface and from an edge thereof, said method comprising placing said surface of said one part in contact with said surface of said other part to thereby provide a pair of contacting and facing surfaces; heating said surfaces and the metal immediately adjacent thereto to an elevated, forge welding temperature by inducing an alternating current in the metal of said parts at and radially adjacent said surfaces with a generally circular induction coil closely adjacent said surfaces, concentric therewith and spaced radially therefrom, said coil having a dimension in a direction parallel to said surfaces approximately equal to the dimension in said last-mentioned direction of said surfaces to confine said current to a relatively narrow path in said last-mentioned metal and said current having a reference depth in said metal at said forge welding temperature at least substantially equal to the thickness of the metal between said coil and said surfaces in the direction perpendicular to said surfaces; terminating said current when said surfaces and the metal immediately adjacent thereto reach said forge welding temperature and while substantially all of said metal extending axially of said surface of said other part is still at a lower temperature, said current being of a magnitude sufficient to so heat said surfaces and said metal immediately radially adjacent thereto to said forge welding temperatures before a significant portion of said metal extending axially of said surfaces reaches said forge welding temperature and being of a magnitude less than that which will cause the metal nearest said coil to melt significantly during the time of flow of said current; and pressing said parts together at said surfaces with forge welding pressure at least when said surfaces and said metal immediately adjacent thereto have reached said forge welding temperature.

Claim 16

A method of forge welding together a pair of dissimilar metal parts, one part having a surface in the shape of a generally circular band and the other part having a surface corresponding in shape to said surface of said one part but of a different diameter and having metal extending in an axial direction with respect to its surface and from an edge thereof, said method comprising placing said surface of said one part in contact with said surface of said other part to thereby provide a pair of contacting and facing surfaces; heating said surfaces and the metal immediately adjacent thereto to an elevated, forge welding temperature by inducing an alternating current in the metal of said parts at and radially adjacent said surfaces with a generally circular induction coil closely adjacent said surfaces, concentric therewith and spaced radially therefrom, said coil having a dimension in a direction parallel to said surfaces approximately equal to the dimension in said last-mentioned direction of said surfaces to confine said current to a relatively narrow path in said last-mentioned metal and said current having a reference depth in said metal at said forge welding temperature at least substantially equal to the thickness of the metal between said coil and said surfaces in the direction perpendicular to said surfaces; terminating said current when said surfaces and the metal immediately adjacent thereto reach said forge welding temperature and while substantially all of said metal extending axially of said surface of said other part is still at a lower temperature, said current being of a magnitude sufficient to so heat said surfaces and said metal immediately radially adjacent thereto to said forge welding temperatures before a significant portion of said metal extending axially of said surfaces reaches said forge welding temperature and being of a magnitude less than that which will cause the metal nearest said coil to melt significantly during the time of flow of said current; and pressing said parts together at said surfaces with forge welding pressure at least when said surfaces and said metal immediately adjacent thereto have reached said forge welding temperature.

Claim 17

A method of forge welding together a pair of dissimilar metal parts, one part having a surface in the shape of a generally circular band and the other part having surface corresponding in shape and size to said surface of said one part but of a different diameter and having metal extending in an axial direction with respect to its said surface and from an edge thereof, said method comprising placing said surface of said one part in contact with said surface of said other part to thereby provide a pair of contacting and facing surfaces; heating said surfaces and the metal immediately adjacent thereto to an elevated, forge welding temperature by inducing an alternating current in the metal of said parts at and adjacent said surfaces with a generally circular induction coil closely adjacent said surfaces, concentric therewith and spaced axially therefrom, said coil having a dimension in a direction perpendicular to said surfaces approximately equal to the dimension in said last-mentioned direction of the metal adjacent said surfaces to be heated to confine said current to a relatively narrow path in said last-mentioned metal and said current having a reference depth in said metal at said forge welding temperature at least substantially equal to the dimension of said surfaces in the direction parallel to said surfaces; terminating said current when said surfaces and the metal immediately adjacent thereto reach said forge welding temperature and while substantially all of said metal extending axially of said surface of said other part is still at a lower temperature, said current being of a magnitude sufficient to so heat said surfaces and said metal immediately adjacent thereto to said forge welding temperature before a significant portion of said metal extending axially of said surfaces reaches said forge welding temperature and being of a magnitude less than that which will cause the metal nearest said coil to melt significantly during the time of flow of said current; and pressing said parts together at said surfaces with forge welding pressure at least when said surfaces and said metal immediately adjacent thereto have reached said forge welding temperature.

Claim 18

A method of forge welding together a pair of dissimilar metal parts, one part having a surface in the shape of a generally circular band and the other part having surface corresponding in shape and size to said surface of said one part but of a different diameter and having metal extending in an axial direction with respect to its said surface and from an edge thereof, said method comprising placing said surface of said one part in contact with said surface of said other part to thereby provide a pair of contacting and facing surfaces; heating said surfaces and the metal immediately adjacent thereto to an elevated, forge welding temperature by inducing an alternating current in the metal of said parts at and adjacent said surfaces with a generally circular induction coil closely adjacent said surfaces, concentric therewith and spaced axially therefrom, said coil having a dimension in a direction perpendicular to said surfaces approximately equal to the dimension in said last-mentioned direction of the metal adjacent said surfaces to be heated to confine said current to a relatively narrow path in said last-mentioned metal and said current having a reference depth in said metal at said forge welding temperature at least substantially equal to the dimension of said surfaces in the direction parallel to said surfaces; terminating said current when said surfaces and the metal immediately adjacent thereto reach said forge welding temperature and while substantially all of said metal extending axially of said surface of said other part is still at a lower temperature, said current being of a magnitude sufficient to so heat said surfaces and said metal immediately adjacent thereto to said forge welding temperature before a significant portion of said metal extending axially of said surfaces reaches said forge welding temperature and being of a magnitude less than that which will cause the metal nearest said coil to melt significantly during the time of flow of said current; and pressing said parts together at said surfaces with forge welding pressure at least when said surfaces and said metal immediately adjacent thereto have reached said forge welding temperature.