US 6,199,744 B1Granted

Friction welding process and shielding gas shower for carrying out the process

AssigneeMTU Motoren- und Turbinen-Union Muenchen GmbH

InventorsDieter Schneefeld, Erich Thaler, Georg Muschal, Karl Katheder

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Abstract

The invention relates to a friction welding process for mounting blades of a blade carrier (1) of a flow machine as well as a shielding gas shower for supplying gas to welding surfaces. To achieve this, a plurality of longitudinally extending welding surfaces (5a) are provided on the circumference of the blade carrier (1), are oriented at a blade angle β relative to the rotation axis (R) of the blade carrier (1), and are respectively welded together with a welding surface (5b) of a blade (2). The welding temperature necessary for joining the bodies (blade carrier (1), blade (2)) is achieved by pressing together the welding surfaces (5a,b) and simultaneous oscillating relative motion (P) of the bodies (1, 2) in the welding plane (E), whereby a shielding gas (S) flows around the welding surfaces (5a,b) during the relative motion (P). The shielding gas flow S follows the contour of the blade carrier and the blade and thus serves to provide a closed shielding gas curtain for protecting the welding surface. In order to ensure a gas supply to the welding surfaces from all sides to the extent possible during the relative motion, the shielding gas shower, which is stationary relative to one of the bodies, comprises a gas outlet opening facing the welding surfaces.

Claims15

Dependent claims

A friction welding process for mounting a blade on a blade carrier of a flow machine, wherein said blade carrier has a circumference and a carrier welding surface provided on said circumference and extending longitudinally oriented at a blade angle β relative to a line extending parallel to a rotation axis of said blade carrier on said circumference, and wherein said blade has a blade welding surface, said process comprising the steps of:

a) placing said blade so that said blade welding surface contacts said carrier welding surface;
b) orienting said blade on said carrier welding surface so that a longitudinal dimension of a cross-section of said blade extends at said blade angle β;
c) moving said blade and said blade carrier in an oscillatory motion relative to each other while contacting and pressing said blade against said blade carrier with a compressive force normal to said blade welding surface so as to frictionally generate a welding temperature sufficient to weld said blade to said blade carrier, wherein respective edge portions of said blade welding surface and said carrier welding surface are intermittently moved out of contact with each other and exposed due to said oscillatory motion;
and
d) flowing a shielding gas flow concurrently with said step of moving said blade and said blade carrier, while directing said shielding gas flow to flow in a flow direction that corresponds to said blade angle β directly along said intermittently exposed respective edge portions of said welding surfaces and directly along a circumference of said blade carrier to provide a shielded welding area that encompasses said carrier welding surface to which said blade is being welded.

2 more elements

A combination of a shielding gas apparatus, a blade carrier, a blade that is to be frictionally welded onto said blade carrier, and a blade moving device adapted to relatively move said blade and said blade carrier, wherein:

said blade carrier is bounded by a circumferential surface that curves circularly about a center axis and that includes a carrier welding surface;
said blade includes a blade body and a blade welding surface, which is arranged and pressed into contact with said carrier welding surface;
said blade is oriented with a chord line of said blade extending at a blade angle β relative to a straight line parallel to said center axis on said circumferential surface;
said blade moving device is adapted to move said blade oscillatingly back-and-forth in an oscillation range (b) in a motion direction tangent to said circumferential surface in a plane perpendicular to said center axis, so as to develop frictional heat in said blade welding surface and said carrier welding surface;
said shielding gas apparatus is mounted stationary relative to one of said blade and said blade carrier;
said shielding gas apparatus comprises a housing and a gas supply conduit communicating into said housing, wherein said housing has at least one gas outlet opening oriented so as to direct a flow of shielding gas from said apparatus onto said blade in a direction perpendicular to said motion direction;
said apparatus is spaced away from said blade perpendicular to said motion direction;
and
said at least one gas outlet opening extends over an arcuate length (l) parallel to said motion direction, wherein said arcuate length (l) is at least equal to said oscillation range (b), so that said at least one gas outlet opening is adapted to form said flow of shielding gas as a partial cylindrical gas curtain that flows along said circumferential surface around said blade while completely enveloping said oscillation range (b).

6 more elements

Dependencies are inferred from the claim text.