Hardbanding Method and Apparatus
AssigneePostle Industries, Inc.
InventorRobert F. Miller
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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.
Claims25
1-16. (canceled)
A hardbanded tool joint comprising:
- an internal lining comprising polymer;
- a base metal zone comprising a base metal;
- a base metal heat affected zone (HAZ) having a Rockwell hardness of about 40 Rockwell Hardness (Rc) or less;
- a previously applied hardband weld zone comprising a hardband metal;
- a stringer bead weld zone comprising a stringer weld metal;
- and
- wherein the base metal heat affected zone (HAZ) is between the base metal and the previously applied hardband weld zone.
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 the 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 and also extending above a top surface of said pipe, a secondary heat-affected zone at least partially in said prior hardbanding alloy, a depth of said secondary heat-affected zone less than a depth of said base metal heat-affected zone.
Dependencies are inferred from the claim text.