Hardbanding method and apparatus
AssigneePostle Industries, Inc.
InventorRobert F. Miller
Life of this patent
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Abstract
Various methods of hardbanding an apparatus are described. In one aspect of the invention an improved method of re-applying a hardbanding alloy to worn tool joints of a previously hardbanded drill pipe results in preservation of the metallurgical properties of the drill pipe and preservation of the internal polymer coating that lines the drill pipe. A method for applying hardbanding includes arc welding a consumable metal welding wire to a tool joint having a surface temperature that ranges from about 50° F. to about 170° F. and the arc welding power supply utilizes DC current. The method herein produces a hardbanded tool joint comprising a heat affected zone (HAZ) of a based metal having a Rockwell hardness of 40 Rc or less.
Claims32
1-29. (canceled)
A hardbanding on a previously hardbanded tool joint of a pipe;
- said hardbanding comprises a pipe having a tool joint;
- an outer surface of a portion of said pipe having a prior hardbanding alloy and a base metal heat-affected zone formed during application of said prior hardbanding alloy;
- said base metal heat-affected zone extending about sides and bottom of said prior hardbanding alloy;
- said base metal heat-affected zone extending a greater depth into said tool joint than said prior hardbanding alloy;
- a secondary hardfacing alloy on at least a portion of a top surface of said prior hardbanding alloy;
- a top surface of said secondary hardfacing alloy extending above said top surface of said prior hardfacing alloy;
- a secondary heat-affected zone at least partially in said prior hardbanding alloy;
- a maximum depth of said secondary heat-affected zone is position above a bottom of said base metal heat-affected zone;
- said base metal heat-affected zone has a hardness of no greater than 40 Rc prior to said secondary hardbanding alloy being applied to said pipe.
A method of hardbanding a pipe in a region of said pipe that has been previously hardbanded, the method comprising:
- providing said pipe, an outer surface of a portion of said pipe having a prior hardbanding alloy and a base metal heat-affected zone formed during application of said prior hardbanding alloy, said base metal heat-affected zone extending at least partially about the sides and bottom of said prior hardbanding alloy, said base metal heat-affected zone extending a greater depth into said region of said pipe than said prior hardbanding alloy;
- and,
- applying a secondary hardbanding alloy on at least a portion of a top surface of said prior hardbanding alloy onto at least a portion of said top surface of said prior hardbanding alloy, a top surface of said secondary hardbanding alloy extending above said top surface of said prior hardbanding alloy and also extending above a top surface of said pipe, said step of applying said secondary hardbanding alloy forms a secondary heat-affected zone at least partially in said prior hardbanding alloy, a depth of said secondary heat-affected zone is less than a depth of said base metal heat-affected zone;
- said base metal heat-affected zone has a hardness of no greater than 40 Rc prior to said secondary hardbanding alloy being applied to said pipe.
Dependencies are inferred from the claim text.