Post-boriding processes for treating pipe and recovering boronizing powder

Abstract

A process comprising: placing a boronizing powder composition in a metal pipe comprising a first end, a second end, an inside surface and an outside surface; heating the pipe to form a borided layer on the inside surface, and spent boronizing powder; removing the spent boronizing powder from the pipe, thereby forming an empty boronized pipe; heating the empty boronized pipe to above its austenitizing temperature, thereby forming an austenitized pipe; quenching the austenitized pipe, thereby forming a quenched pipe; tempering the quenched pipe, thereby forming a tempered pipe; and threading the tempered pipe.

We claim: 
     
         1 . A process comprising:
 placing a boronizing powder composition in a metal pipe comprising a first end, a second end, an inside surface and an outside surface;   heating the pipe to form a borided layer on the inside surface, and spent boronizing powder;   removing the spent boronizing powder from the pipe, thereby forming an empty boronized pipe;   heating the boronized pipe to above its austenitizing temperature, thereby forming an austenitized pipe;   quenching the austenitized pipe, thereby forming a quenched pipe; and   tempering the quenched pipe, thereby forming a tempered pipe.   
     
     
         2 . The process of  claim 1  wherein the borided layer comprises 80.0 to 100.0 vol % Fe 2 B and 0 to 20.0 vol % FeB, based on the total amount of the Fe 2 B and FeB. 
     
     
         3 . The process of  claim 1  wherein the heating to form the austenitized pipe is an induction heating. 
     
     
         4 . The process of  claim 1  wherein the heating to form the austenitized pipe is a furnace heating. 
     
     
         5 . The process of  claim 1  wherein the tempered pipe meets the mechanical property requirements for yield strength and tensile strength of API 5CT specification Grade L80. 
     
     
         6 . The process of  claim 1  wherein the borided layer is physically uniform. 
     
     
         7 . The process of  claim 1  wherein the heating to form the austenitized pipe is from 1400 to 2000° F. 
     
     
         8 . The process of  claim 1  wherein the austenitized pipe is quenched to a temperature of 40 to 200° F. 
     
     
         9 . The process of  claim 1  wherein the quenched pipe is tempered at a temperature from 250 to 1375° F. 
     
     
         10 . The process of  claim 1  wherein the quenching is conducted with water, oil, brine, polymer, salt or mixtures thereof. 
     
     
         11 . The process of  claim 1  wherein the tempering is induction tempering. 
     
     
         12 . The process of  claim 1  wherein the tempering is furnace tempering. 
     
     
         13 . The process of  claim 1  where the boride layer of the tempered pipe is physically uniform. 
     
     
         14 . A pipe produced by the process of  claim 1 . 
     
     
         15 . A boronized pipe that has been hardened and tempered after boriding to meet mechanical properties of 80 ksi minimum yield strength and 95 minimum ksi tensile strength. 
     
     
         16 . The boronized pipe of  claim 15  comprising a borided layer Fe 2 B content of 80.0 to 100.0 vol % and a borided layer FeB content of 0 to 20.0 vol %, based on the total amount of the borided layer. 
     
     
         17 . The boronized pipe of  claim 16  wherein the borided layer Fe 2 B content is 95.0 to 100.0 vol % and the FeB content is 0 to 5.0 vol %, based on the total amount of the borided layer. 
     
     
         18 . The boronized pipe of  claim 16  wherein the borided layer is physically uniform. 
     
     
         19 . A process for treating a boronized pipe comprising a borided layer on its interior surface, the process comprising:
 heating the boronized pipe to above its austenitizing temperature, thereby forming an austenitized pipe;   quenching the austenitized pipe, thereby forming a quenched pipe; and   tempering the quenched pipe, thereby forming a tempered pipe.   
     
     
         20 . The process of  claim 19  wherein the borided layer comprises 80.0 to 100.0 vol % Fe 2 B and 0 to 20.0 vol % FeB, based on the total amount of the borided layer. 
     
     
         21 . The process of  claim 20  wherein the Fe 2 B content of the borided layer is from 95.0 to 100.0 vol % and the FeB content of the borided layer is 0 to 5.0 vol %, based on the total amount of the borided layer. 
     
     
         22 . The process of  claim 19  wherein the tempered pipe meets the mechanical property requirements for tensile strength and yield strength per API 5CT specification Grade L80. 
     
     
         23 . The process of  claim 19  wherein the borided layer is physically uniform. 
     
     
         24 . A pipe produced by the process of  claim 19 . 
     
     
         25 . A process comprising heating a boronized pipe comprising a borided layer on the pipe's interior surface, to above its austenitizing temperature, thereby forming an austenitized pipe; and quenching the austenitized pipe, thereby forming a quenched pipe 
     
     
         26 . The process of  claim 25  wherein the borided layer comprises 80.0 to 100.0 vol % Fe 2 B and 0 to 20.0 vol % FeB, based on the total amount of Fe 2 B and FeB. 
     
     
         27 . The process of  claim 26  wherein the Fe 2 B content of the borided layer is from 95.0 to 100.0 vol % and the FeB layer is from 0 to 5 vol %, based on the total amount of Fe 2 B and FeB. 
     
     
         28 . The process of  claim 25  wherein the borided layer is physically uniform. 
     
     
         29 . A pipe produced by the process of  claim 25 . 
     
     
         30 . The process of  claim 1  wherein the thickness of the borided layer is from 0.0005 to 0.020 inches. 
     
     
         31 . The process of  claim 30  wherein the thickness of the borided layer is from 0.002 to 0.015 inches. 
     
     
         32 . The process of  claim 1  wherein the boronizing powder composition comprises: 0.5 to 25.0 wt % of a boron source selected from B 4 C, amorphous boron, calcium hexaboride, borax or mixtures thereof; 1.0 to 25.0 wt % of an activator selected from KBF 4 , ammonia chloride, cryolite, sodium fluoride, ammonium bifluoride, potassium fluoride, calcium fluoride, or mixtures thereof; and 50.0 to 98.5 wt % of a diluent selected from SiC, alumina, zirconia, or mixtures thereof, based on the total weight of the boron source, activator and diluent. 
     
     
         33 . The process of  claim 1  wherein the boronizing powder composition comprises 0.5 to 25.0 wt % of a boron source selected from B 4 C, amorphous boron, calcium hexaboride, borax or mixtures thereof; 1.0 to 25.0 wt % of an activator selected from KBF 4 , ammonia chloride, cryolite, sodium fluoride, ammonium bifluoride, potassium fluoride, calcium fluoride, or mixtures thereof; and 50.0 to 98.5 wt % of a sintering reduction agent selected from carbon black, graphite, activated carbon, charcoal, or mixtures thereof, based on the total weight of the boron source, activator and sintering reduction agent. 
     
     
         34 . The process of  claim 1  wherein the boronizing powder composition comprises 0.5 to 4.5 wt % of a boron source selected from B 4 C, amorphous boron, calcium hexaboride, borax or mixtures thereof; 45.5 to 88.5 wt % of a diluent selected from SiC, alumina, zirconia or mixtures thereof; 1.0 to 20.0 wt % of an activator selected from KBF 4 , ammonia chloride, cryolite, sodium fluoride, ammonium bifluoride, potassium fluoride, calcium fluoride, or mixtures thereof; and 10.0 to 30.0 wt % of a sintering reduction agent selected from carbon black, graphite, activated carbon, charcoal or mixtures thereof. 
     
     
         35 . The process of  claim 1  wherein the boronizing powder composition comprises 0.5 to 3.0 wt % of a boron source selected from B 4 C, amorphous boron, calcium hexaboride, borax or mixtures thereof; 82.0 to 98.5 wt % of a stream selected from diluents and sintering reduction agents, the diluents being selected from SiC, alumina, zirconia or mixtures thereof, and the sintering reduction agent being selected from carbon black, graphite, activated carbon, charcoal or mixtures thereof; and 1.0 to 15.0 wt % of an activator selected from KBF 4 , ammonia chloride, cryolite, sodium fluoride, ammonium bifluoride, potassium fluoride, calcium fluoride, or mixtures thereof. 
     
     
         36 . A process comprising:
 placing a boronizing powder composition in a metal pipe comprising a first end, a second end, an inside surface and an outside surface;   heating the pipe to a boronizing temperature, thereby forming a borided layer on the inside surface, and spent boronizing powder; and   removing the spent boronizing powder from the pipe;   wherein the spent boronizing powder is removed from the metal pipe with a closed transport system.   
     
     
         37 . The process of  claim 36  wherein the closed transport system is selected from pneumatic conveyance, screw conveyer, or combinations thereof. 
     
     
         38 . The process of  claim 1  wherein the removed spent boronizing powder is further treated with screens, sieves or by air classification, thereby forming a treated boronizing powder stream. 
     
     
         39 . The process of  claim 1  wherein the removed spent boronizing powder is treated by adding an additive component, thereby forming a first recycle stream. 
     
     
         40 . The process of  claim 38  wherein the treated boronizing powder stream is treated by adding an additive component, thereby forming a second recycle stream. 
     
     
         41 . The process of  claim 39  wherein the additive component is selected from a second boronizing powder composition, a boron source, a sintering reduction agent, an activator, a diluent or mixtures thereof. 
     
     
         42 . The process of  claim 40  wherein the additive component is selected from a second boronizing powder composition, a boron source, a sintering reduction agent, an activator, a diluent or mixtures thereof. 
     
     
         43 . The process of  claim 39  wherein the first recycle stream is recycled to a powder boronizing process. 
     
     
         44 . The process of  claim 40  wherein the second recycle stream is recycled to a powder boronizing process. 
     
     
         45 . The process of  claim 36  wherein the boronizing powder composition comprises: 0.5 to 25.0 wt % of a boron source selected from B 4 C, amorphous boron, calcium hexaboride, borax or mixtures thereof; 1.0 to 25.0 wt % of an activator selected from KBF 4 , ammonia chloride, cryolite, sodium fluoride, ammonium bifluoride, potassium fluoride, calcium fluoride, or mixtures thereof; and 50.0 to 98.5 wt % of a diluent, based on the total weight of the boron source, activator and diluent. 
     
     
         46 . The process of  claim 45  wherein the boronizing powder composition comprises: 2.0 to 20.0 wt % of the boron source; 2.0 to 20.0 wt % of the activator selected from KBF 4 , ammonia chloride, cryolite, sodium fluoride, ammonium bifluoride, potassium fluoride, calcium fluoride, or mixtures thereof; and 60.0 to 96.0 wt % of the diluent selected from SiC, alumina, zirconia, or mixtures thereof; based on the total weight of the boron source, activator and diluent. 
     
     
         47 . The process of  claim 46  wherein the boronizing powder composition comprises 2.0 to 6.0 wt % of the boron source; 2.0 to 8.0 wt % of the activator; and 86.0 wt % to 96.0 wt % of the diluent, based on the total weight of the boron source, activator and diluent. 
     
     
         48 . The process of  claim 36  wherein the boronizing powder composition comprises 0.5 to 25.0 wt % of a boron source selected from B 4 C, amorphous boron, calcium hexaboride, borax or mixtures thereof; 1.0 to 25.0 wt % of an activator selected from KBF 4 , ammonia chloride, cryolite, sodium fluoride, ammonium bifluoride, potassium fluoride, calcium fluoride, or mixtures thereof; and 50.0 to 98.5 wt % of an sintering reduction agent selected from carbon black, graphite or mixtures thereof, based on the total weight of the boron source, activator and sintering reduction agent. 
     
     
         49 . The process of  claim 48  wherein the boronizing powder composition comprises 2.0 to 20.0 wt % of the boron source; 2.0 to 20.0 wt % of the activator and 60.0 to 96.0 wt % of the sintering reduction agent, based on the total weight of the boron source, activator and sintering reduction agent. 
     
     
         50 . The process of  claim 49  wherein the boronizing powder composition comprises 2.0 to 6.0 wt % of the boron source; 2.0 to 8.0 wt % of the activator and 86.0 to 96.0 wt % of the sintering reduction agent, based on the sintering reduction agent. 
     
     
         51 . The process of  claim 36  wherein the boronizing powder composition comprises 0.5 to 4.5 wt % of a boron source selected from B 4 C, amorphous boron, calcium hexaboride, borax or mixtures thereof; (b) 45.5 to 88.5 wt % of a diluent selected from SiC, alumina, zirconia, or mixtures thereof; (c) 1.0 to 20.0 wt % of an activator selected from KBF 4 , ammonia chloride, cryolite, sodium fluoride, ammonium bifluoride, potassium fluoride, calcium fluoride, or mixtures thereof; and (d) 10.0 to 30.0 wt % of a sintering reduction agent selected from carbon black, graphite, activated carbon or mixtures thereof. 
     
     
         52 . The process of  claim 36  wherein the borided layer has a thickness from 0.0005 to 0.020 inches. 
     
     
         53 . The process of  claim 52  wherein the thickness of the borided layer is from 0.002 to 0.015 inches. 
     
     
         54 . The process of  claim 36  wherein the borided layer comprises 80.0 to 100.0 vol % Fe 2 B and 0 to 20.0 vol % FeB, based on the total amount of Fe 2 B and FeB. 
     
     
         55 . The process of  claim 54  wherein the borided layer comprises 95.0 to 100.0 vol % Fe 2 B and 0 to 5.0 vol % FeB, based on the total amount of Fe 2 B and FeB. 
     
     
         56 . A process comprising:
 placing a boronizing powder composition in a metal pipe comprising a first end, a second end, an inside surface and an outside surface;   heating the pipe to a boriding temperature, thereby forming a borided layer on the inside surface, and spent boriding powder; and   removing the spent boriding powder from the pipe,   wherein the boronizing powder is placed in the metal pipe by conveying the powder to the pipe using a closed transport system selected from pneumatic conveying, rotary valve, screw conveyer or combinations thereof.   
     
     
         57 . The process of  claim 56  wherein the powder is conveyed by pneumatic conveying. 
     
     
         58 . The process of  claim 56  wherein the powder is conveyed by rotary valve. 
     
     
         59 . The process of  claim 56  wherein the powder is conveyed by screw conveyer. 
     
     
         60 . A process comprising:
 placing a boronizing powder composition in a metal pipe comprising a first end, a second end, an inside surface and an outside surface;   heating the pipe to a boriding temperature, thereby forming a borided layer on the inside surface, and spent boriding powder; and   removing the spent boriding powder from the pipe;   wherein the boronizing powder is placed in the metal pipe by conveying the powder to the pipe using a closed transport system, and the spent boronizing powder is removed from the metal pipe by a closed transport system.   
     
     
         61 . The metal pipe of  claim 14  wherein the metal is selected from plain carbon steel, alloy steel, tool steel, stainless steel, nickel-based alloys, cobalt-based alloys, cast iron, ductile iron, molybdenum, or stellite. 
     
     
         62 . A process comprising transporting oil or gas in an oil well with the pipe of  claim 15 . 
     
     
         63 . A process comprising transporting oil or gas in an oil well with the pipe of  claim 24 . 
     
     
         64 . A process comprising:
 placing a boronizing powder composition in a metal pipe comprising a first end, a second end, an inside surface and an outside surface;   heating the pipe to form a borided layer on the inside surface, and spent boronizing powder;   removing the spent boronizing powder from the pipe, thereby forming an empty boronized pipe;   heating the empty boronized pipe to above its austenitizing temperature, thereby forming an austenitized pipe;   quenching the austenitized pipe, thereby forming a quenched pipe;   tempering the quenched pipe, thereby forming a tempered pipe; and   threading the tempered pipe.   
     
     
         65 . A process comprising:
 boronizing an unthreaded pipe, thereby forming an unthreaded boronized pipe; and   threading the unthreaded boronized pipe.   
     
     
         66 . A pipe made by the process of  claim 64 . 
     
     
         67 . A pipe made by the process of  claim 65 . 
     
     
         68 . A process for boronizing a metal pipe comprising a flared first end, a second end, an inside surface and an outside surface, the process comprising:
 fastening a first split-bushing end cap on the flared first end;   depositing boronizing powder in the pipe;   fastening a plate or second split bushing end cap on the second end; and   
       heating the pipe to a temperature from 1400° F. to 1900° F., thereby forming a borided layer on the inside surface, and generating spent reaction gases and spent boriding powder. 
     
     
         69 . The process of  claim 68  wherein the second split bushing end cap is fastened on the second end. 
     
     
         70 . The process of  claim 68  wherein the second end is flared. 
     
     
         71 . The process of  claim 69  wherein the first end and second end are unthreaded. 
     
     
         72 . The process of  claim 69  further comprising cooling the pipe and threading the ends. 
     
     
         73 . The process of  claim 68  wherein the split-end bushing comprises at least one curved section. 
     
     
         74 . A pipe produced by the process of  claim 68 . 
     
     
         75 . A process for boronizing a metal pipe comprising an unthreaded first end, an unthreaded second end, an interior, an inside surface and an outside surface;
 fastening a first plate to the first end of the pipe;   placing boronizing powder in the interior of the pipe;   fastening a second plate to the second end of the pipe;   heating the pipe to a temperature from 1400° F. to 1900° F., thereby forming a borided layer on the inside surface, and generating spent reaction gases and spent boriding powder.   
     
     
         76 . The process of  claim 73  wherein the first plate and second plate are fastened onto the ends of the pipe by welding or joining. 
     
     
         77 . A process comprising:
 placing a boronizing powder composition in a metal pipe comprising a first end, a second end, an inside surface and an outside surface;   heating the pipe to form a borided layer on the inside surface, and spent boronizing powder;   heating the pipe with the borided layer to above its austenitizing temperature, thereby forming an austenitized pipe;   quenching the austenitized pipe, thereby forming a quenched pipe; and   tempering the quenched pipe, thereby forming a tempered pipe.