US3922038A - Wear resistant boronized surfaces and boronizing methods - Google Patents

Wear resistant boronized surfaces and boronizing methods Download PDF

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US3922038A
US3922038A US387566A US38756673A US3922038A US 3922038 A US3922038 A US 3922038A US 387566 A US387566 A US 387566A US 38756673 A US38756673 A US 38756673A US 3922038 A US3922038 A US 3922038A
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carburized
boronized
bearing pin
depth
rotatable cutter
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Stanley R Scales
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Hughes Tool Co
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Priority to CA194,785A priority patent/CA1006869A/en
Priority to BR2519/74A priority patent/BR7402519A/en
Priority to AR253726A priority patent/AR202648A1/en
Priority to GB2208474A priority patent/GB1435045A/en
Priority to SE7409633A priority patent/SE397841B/en
Priority to IT26005/74A priority patent/IT1017921B/en
Priority to US05/616,537 priority patent/US4012238A/en
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    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21BEARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B10/00Drill bits
    • E21B10/08Roller bits
    • E21B10/22Roller bits characterised by bearing, lubrication or sealing details
    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/12All metal or with adjacent metals
    • Y10T428/12493Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
    • Y10T428/12771Transition metal-base component
    • Y10T428/12861Group VIII or IB metal-base component
    • Y10T428/12951Fe-base component
    • Y10T428/12958Next to Fe-base component

Definitions

  • ABSTRACT Disclosed herein are treatments for the manufacture of wear resistant steel surfaces, which are carburized, boronized, quenched and tempered for extreme surface hardness, with a strong, tough supporting base that minimizes fracturing of the brittle boronized case.
  • This invention relates in general to surface treatments of metals, particularly to those for steels requiring exceptional wear resistance under heavy loads such as those imposed upon earth boring drill bit bearings.
  • the bearing surfaces of rotatable cutters in earth boring drill bits are commonly carburized, hardened and tempered to increase their wear resistance. Such surfaces sometimes have regions of soft anti-galling material such as silver or silver alloy, as disclosed in US. Pat. No. 3,235,316.
  • the mating surfaces of the opposing bearing shafts often include deposits of hard metal of cobalt based alloy of the Stellite series.
  • a wear resistant surface for steel such as a bearing surface in an earth boring drill bit may be constructed advantageously by a process that includes carburization, boronizing the resulting carburized surface, hardening in a manner to protect the boronized case from decarburizing, and then tempering.
  • carburizing and boronizing to the requisite depths hardening in a manner to produce a martensitic grain structure in the carburized case, and tempering to thereafter produce tempered martensite, a surface of extreme hardness results with a strong and tough supporting base. This base minimizes fracturing of the brittle boronized case since it is resistant to deformation and provides a satisfactory support for the boronized case.
  • FIG. I is a fragmentary perspective view, partially in section, showing an earth boring drill bit and typical bearing which receives the metallurgical treatment described herein.
  • FIG. 2 is a cross-sectional view as seen looking along the lines IIII of FIG. 1.
  • the numeral 11 in the drawing designates an earth boring drill bit having a plurality of head sections or legs 13 joined by suitable means such as welding (not shown) and threaded at 15 for attachment to a supportive drill string member.
  • suitable means such as welding (not shown) and threaded at 15 for attachment to a supportive drill string member.
  • One of the prior art lubrication and compensator systems 17, such as illustrated in FIG. 1 feeds lubricant through a passageway 19 and into a bearing region formed between a cantilevered shaft or pin 21 of the head section and a rotatable cutter 23 having teeth 25 for disintegrating earth.
  • Suitable seal 2 means 27 prevent the escape of lubricant from the bearing region, as explained in US. Pat. No. 3,397,928.
  • bearings in an earth boring drill often include a primary friction region 29, an antifriction ball bearing and cutter retainer region 31, and radial and thrust friction bearing regions designated respectively 33 and 35.
  • FIG. 2 shows in cross-section the cantilevered bearing pin 21 and rotatable cutter 23.
  • the cylindrical surface 35 of the bearing pin 21 receives the special treatment of the present invention, while the opposing surface of the rotatable cutter 23 receives a prior art treatment such as that described in US. Pat. No. 3,235,316, preferably that using silver alloy.
  • This patent teaches that improved friction bearings for earth boring drill bits result from the use of indentations filled with a soft anti-galling material such as silver or silver alloy 37 in a surface having a hardness and wear resistance comparable to carburized and hardened steel.
  • this invention utilizes four primary method or process steps: carburizing, boronizing, hardening and tempering, each of which will be described separately by way of example.
  • the initial step in the method of this invention requires carburization of a steel bearing surface such as the primary friction bearing region 29.
  • One of the prior art carburization methods may be used.
  • Gas carburizing is a well known art and is the preferred method. It is described on pp.
  • Carburizing temperature 1700F.
  • Carburizing time 9 hours at 1700F.
  • Carburizing atmosphere Generated endothermic gas enriched with methane to have a carbon potential of 1.35% carbon.
  • Pack carburizing is another well known art that may be used. It is described on pp. 114-118 of Volume 2 of the same Metals Handbook.
  • An example of pack carburizing of the bearing surfaces of a rock bit head section made of A.I.S.I. 4815 steel is as follows:
  • Carburizing compound packed around the surface to be carburized: Charcoal, (6 to 14 mesh size), energized with about 4% BaCO and about 1.5% CaCO Carburizing temperature: 1700F. Carburizing time: Nine hours at 1700F.
  • Liquid carburizing is another well known art to the metals industry. It is described on pp. l33145 of Volume 2 of the same Metals Handbook. While not actually used for this invention, it is anticipated that 9 hours at 1700F. in a salt bath containing about 6 16% sodium cyanide and 30 55% barium chloride would produce a satisfactory carburized case to a depth of about 0.065 inch.
  • the second step of the method of this invention is boronizing of the previously carburized surfaces.
  • Pack boronizing is the preferred technique and is a relatively new art.
  • An example of boronizing a carburized bearing surface of an A.l.S.l. 4815 steel head section is as follows:
  • Boronizing time 5 hours at temperature in a furnace with a carbon potential of 1.00%.
  • Gas boronizing is an alternate technique in the prior art. It is described in U.S. Pat. No. 2,494,267, Surface Hardening of Ferrous Metals, Schlesinger and Schaffer, Jan. 10, 1950. The method described utilizes gaseous diborane (B 11 at about 700C (1292F).
  • Liquid boronizing is another prior art boronizing method. It is described in two papers: Boronizing of Steel by D. C. Durrill and Dr. Donald D. Allen, Magnetic Propulsion Systems, Inc. and Boriding Steels for Wear Resistance by Howard C. Fielder and Richard J. Sieraski, General Electric Co. (Metal Progress, Feb. 1971, pp. 101-107).
  • liquid salt bath composition Neither gives the liquid salt bath composition, but the latter paper states that it contains flourides of lithium, sodium, potassium, and boron. Temperatures and times reported vary from l450 1650F. and from 15 minutes to 36 hours.
  • the third and fourth steps in the method of this in-' vention are hardening and tempering of the carburized, boronized and cleaned steel surfaces.
  • the hardening and tempering of carburized steel is a well known art.
  • the hardening, usually quenching in agitated oil, from a temperature of at least 1390F. can be performed using one of several procedures, such as the following two for carburized A.l.S.I. 4815 steel and produces a martensitic case:
  • Quenching from a carburizing or reducing atmosphere prevents decarburization or oxidation of the boronized case.
  • a suitable coating such as copper plating may be used.
  • a suitable atmosphere is one similar to the previously explained methane enriched endothermic gas except slightly higher in CO (about 0.4 to 0.8%) because of the lower temperatures.
  • the tempering temperature is usually low, 290 510F., preferably about 330F. for 1 hour, to toughen the carburized case without appreciably lowering its strength (hardness) to produce tempered martensite.
  • the above described procedures are utilized to produce a carburized foundation on the steel bearing pin 21 of at least 0.060 inch.
  • the boronizing procedure produces a boronized case of at least 0.001 inch (average about 0.004 inch) with a surface hardness in a range of 900 to 2100 KHN.
  • the hardening and tempering procedure develops a hardness in thecarburized foundation in a range of 50 to 64 Rockwell C (550 to 800 KHN).
  • said carburized surface being hardened and tempered by heat treatment
  • the wear resistant boronized surface has a tough and strong supporting base to sustain large loads imposed by a mating friction bearing in said rotatable cutter and avoid brittle fracture.
  • a boronized surface having a depth of at least 0.001
  • said carburized surface being hardened I and tempered by heat treatment
  • the wear resistant boronized surface has a tough and strong supporting base to sustain large loads imposed by a mating friction bearing in said rotatable cutter and avoid brittle fracture.
  • said carburized case being quenched from a temperature to produce a martensitic grain structure
  • said carburized case being tempered to produce a tempered martensitic grain structure
  • the wear resistantboronized surface has a tough and strong supporting base to sustain large loads imposed by a mating friction bearing in said rotatable cutter and avoid brittle fracture.
  • a boronized surface having a depth of at least 0.001
  • said carburized case being quenched from a temperature to produce a martensitic grain structure
  • said carburized case being tempered to produce a tempered martensitic grain structure
  • the wear resistant boronized surface has a tough and strong supporting base to sustain large loads imposed by a mating friction bearing in said rotatable cutter and avoid brittle fracture.
  • a boronized surface having a depth of at least 0.001
  • said carburized case being quenched from a temperature of at least 1390F. to produce a martensitic grain structure
  • said carburized case being tempered from a temperature within a range of 290 through 510F. for about 1 hour to produce a tempered martinsitic grain structure;
  • the wear resistant boronized surface has a tough and strong supporting base to sustain large loads imposed by a mating friction bearing in said rotatable cutter and avoid brittle fracture.
  • the wear resistant boronized surface has a tough and strong supporting base to sustain large loads and avoid brittle fracture.

Abstract

Disclosed herein are treatments for the manufacture of wear resistant steel surfaces, which are carburized, boronized, quenched and tempered for extreme surface hardness, with a strong, tough supporting base that minimizes fracturing of the brittle boronized case.

Description

United States Patent n91 Scales 1451 Nov. 25, 1975 1 1 WEAR RESISTANT BORONIZED SURFACES AND BORONIZING METHODS [75] Inventor: Stanley R. Scales, Houston, Tex.
[73] Assignee: Hughes Tool Company, Houston,
Tex.
[22] Filed: Aug. 10, 1973 [21] App]. No: 387,566
[52] US. Cl. 308/82; 148/165; 148/315; 175/374 [51] Int. Cl. F16C 19/00 [58] Field of Search 308/82, 241; 148/31.5, 148/165; 175/374 [56] References Cited UNlTED STATES PATENTS 3,227,586 1/1966 Spencer 148/165 X 3,275,389 9/1966 Neilson et al 308/82 3,795,551 3/1974 Swirnow 148/3145 3,811,961 5/1974 Weinstein et a1. 148/315 Primary ExaminerCharles J. Myhre Assistant Examiner-James D, Liles Attorney, Agent, or FirmRobert A. Felsman [57] ABSTRACT Disclosed herein are treatments for the manufacture of wear resistant steel surfaces, which are carburized, boronized, quenched and tempered for extreme surface hardness, with a strong, tough supporting base that minimizes fracturing of the brittle boronized case.
8 Claims, 2 Drawing Figures U.S. Patent Nov. 25, 1975 3,922,038
WEAR RESISTANT BORONIZED SURFACES AND BORONIZING METHODS BACKGROUND OF THE INVENTION:
1. Field of the Invention:
This invention relates in general to surface treatments of metals, particularly to those for steels requiring exceptional wear resistance under heavy loads such as those imposed upon earth boring drill bit bearings.
2. Description of the Prior Art:
It has long been known that the surfaces of metals such as steel may be treated with a variety of elements or compositions that combine with the constituents of steel to produce hard wear resistant surfaces. One of the known prior art treatments is carburization. Another is boronizing.
The bearing surfaces of rotatable cutters in earth boring drill bits are commonly carburized, hardened and tempered to increase their wear resistance. Such surfaces sometimes have regions of soft anti-galling material such as silver or silver alloy, as disclosed in US. Pat. No. 3,235,316. The mating surfaces of the opposing bearing shafts often include deposits of hard metal of cobalt based alloy of the Stellite series.
Boronizing of the bearing surfaces of earth boring drill bits has not heretofore been commercially successful, principally due to the brittle nature of the hard surfaces and their shallow depth.
SUMMARY OF THE INVENTION This invention relates to the discovery that a wear resistant surface for steel such as a bearing surface in an earth boring drill bit may be constructed advantageously by a process that includes carburization, boronizing the resulting carburized surface, hardening in a manner to protect the boronized case from decarburizing, and then tempering. By carburizing and boronizing to the requisite depths, hardening in a manner to produce a martensitic grain structure in the carburized case, and tempering to thereafter produce tempered martensite, a surface of extreme hardness results with a strong and tough supporting base. This base minimizes fracturing of the brittle boronized case since it is resistant to deformation and provides a satisfactory support for the boronized case.
BRIEF DESCRIPTION OF THE DRAWING FIG. I is a fragmentary perspective view, partially in section, showing an earth boring drill bit and typical bearing which receives the metallurgical treatment described herein.
FIG. 2 is a cross-sectional view as seen looking along the lines IIII of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS The numeral 11 in the drawing designates an earth boring drill bit having a plurality of head sections or legs 13 joined by suitable means such as welding (not shown) and threaded at 15 for attachment to a supportive drill string member. One of the prior art lubrication and compensator systems 17, such as illustrated in FIG. 1, feeds lubricant through a passageway 19 and into a bearing region formed between a cantilevered shaft or pin 21 of the head section and a rotatable cutter 23 having teeth 25 for disintegrating earth. Suitable seal 2 means 27 prevent the escape of lubricant from the bearing region, as explained in US. Pat. No. 3,397,928.
The above mentioned bearings in an earth boring drill often include a primary friction region 29, an antifriction ball bearing and cutter retainer region 31, and radial and thrust friction bearing regions designated respectively 33 and 35.
FIG. 2 shows in cross-section the cantilevered bearing pin 21 and rotatable cutter 23. The cylindrical surface 35 of the bearing pin 21 receives the special treatment of the present invention, while the opposing surface of the rotatable cutter 23 receives a prior art treatment such as that described in US. Pat. No. 3,235,316, preferably that using silver alloy. This patent teaches that improved friction bearings for earth boring drill bits result from the use of indentations filled with a soft anti-galling material such as silver or silver alloy 37 in a surface having a hardness and wear resistance comparable to carburized and hardened steel.
As previously stated this invention utilizes four primary method or process steps: carburizing, boronizing, hardening and tempering, each of which will be described separately by way of example. The initial step in the method of this invention requires carburization of a steel bearing surface such as the primary friction bearing region 29. One of the prior art carburization methods may be used. Gas carburizing is a well known art and is the preferred method. It is described on pp.
93-l 14 of Volume 2 of the 8th Edition of the Metals Handbook, Heat Treating, Cleaning and Finishing (1964, American Society for Metals). An example of the gas carburizing of the bearing surfaces of a selectively copper plated rock bit head section made of A.I.S.I. 4815 steel is as follows:
Carburizing temperature: 1700F.
Carburizing time: 9 hours at 1700F.
Carburizing atmosphere: Generated endothermic gas enriched with methane to have a carbon potential of 1.35% carbon.
A typical analysis of the carburizing gas (atmosphere) is as follows:
20% C0 (C0 about 0.05%)
This produces a carburized case depth of about 0.065
inch with carbon content at the surface about 1.00%.
Pack carburizing is another well known art that may be used. It is described on pp. 114-118 of Volume 2 of the same Metals Handbook. An example of pack carburizing of the bearing surfaces of a rock bit head section made of A.I.S.I. 4815 steel is as follows:
Carburizing compound (packed around the surface to be carburized): Charcoal, (6 to 14 mesh size), energized with about 4% BaCO and about 1.5% CaCO Carburizing temperature: 1700F. Carburizing time: Nine hours at 1700F.
This produces a carburized case depth of about 0.065
inch with carbon content at the surface about 1.00%.
Liquid carburizing is another well known art to the metals industry. It is described on pp. l33145 of Volume 2 of the same Metals Handbook. While not actually used for this invention, it is anticipated that 9 hours at 1700F. in a salt bath containing about 6 16% sodium cyanide and 30 55% barium chloride would produce a satisfactory carburized case to a depth of about 0.065 inch.
The second step of the method of this invention is boronizing of the previously carburized surfaces. Pack boronizing is the preferred technique and is a relatively new art.
An example of boronizing a carburized bearing surface of an A.l.S.l. 4815 steel head section is as follows:
Compound: Boronizing powder was packed around the carburized bearing surface. This powder was 90% finer than 150 mesh, had 4080% 8 C, 240% (graphite), l4% KHCO with remainder up to 20% in impurities.
Boronizing temperature: 1650F. (in a carburizing atmosphere).
Boronizing time: 5 hours at temperature in a furnace with a carbon potential of 1.00%.
This produced a boronized case depth of about 0.004 inch. Longer boronizing times and/or higherboronizing temperatures can be used for deeper boronized case depth, but a 0.001 to 0.010 inch deep boronized case has less tendency to crack or spall than a deeper case.
Gas boronizing is an alternate technique in the prior art. It is described in U.S. Pat. No. 2,494,267, Surface Hardening of Ferrous Metals, Schlesinger and Schaffer, Jan. 10, 1950. The method described utilizes gaseous diborane (B 11 at about 700C (1292F).
Liquid boronizing is another prior art boronizing method. It is described in two papers: Boronizing of Steel by D. C. Durrill and Dr. Donald D. Allen, Magnetic Propulsion Systems, Inc. and Boriding Steels for Wear Resistance by Howard C. Fielder and Richard J. Sieraski, General Electric Co. (Metal Progress, Feb. 1971, pp. 101-107).
Neither gives the liquid salt bath composition, but the latter paper states that it contains flourides of lithium, sodium, potassium, and boron. Temperatures and times reported vary from l450 1650F. and from 15 minutes to 36 hours.
The third and fourth steps in the method of this in-' vention are hardening and tempering of the carburized, boronized and cleaned steel surfaces.
The hardening and tempering of carburized steel is a well known art. The hardening, usually quenching in agitated oil, from a temperature of at least 1390F. can be performed using one of several procedures, such as the following two for carburized A.l.S.I. 4815 steel and produces a martensitic case:
a. Single quench from a carburizing or reducing atmosphere and a temperature of 1500F.
b. Double quench from a carburizing or reducing atmosphere and temperatures ofrespectively 1550F. and 1435F.
Quenching from a carburizing or reducing atmosphere prevents decarburization or oxidation of the boronized case. A suitable coating such as copper plating may be used. A suitable atmosphere is one similar to the previously explained methane enriched endothermic gas except slightly higher in CO (about 0.4 to 0.8%) because of the lower temperatures.
The tempering temperature is usually low, 290 510F., preferably about 330F. for 1 hour, to toughen the carburized case without appreciably lowering its strength (hardness) to produce tempered martensite.
The above described procedures are utilized to produce a carburized foundation on the steel bearing pin 21 of at least 0.060 inch. The boronizing procedure produces a boronized case of at least 0.001 inch (average about 0.004 inch) with a surface hardness in a range of 900 to 2100 KHN. The hardening and tempering procedure develops a hardness in thecarburized foundation in a range of 50 to 64 Rockwell C (550 to 800 KHN). When such a bearing pin is assembled with a rotatable cutter of the type shown in the drawing and described in U.S. Pat. No. 3,235,316, overall bearing performance is much improved over that obtainable with a carburized bearing surface Results indicate that such a surface performs comparably with much more expensive procedures such as when utilizing a deposit of hard metal of the cobalt based Stellite series in a groove on the bearing pin.
While the invention has been described in only a few of its forms it should be apparent to those skilled in the art that it is not so limited but is susceptible to various. changes and modifications without departing from the spirit thereof.
1 claim:
1. In an earth boring drill bit having at least one rotatable cutter supported on a steel bearing pin, the improvement which comprises:
a carburized friction bearing surface formed on said steel bearing pin;
a boronized surface formed on said carburized bearing surface;
said carburized surface being hardened and tempered by heat treatment;
whereby the wear resistant boronized surface has a tough and strong supporting base to sustain large loads imposed by a mating friction bearing in said rotatable cutter and avoid brittle fracture. 1
2. In an earth boring drill bit having at least one rotatable cutter supported on a steel bearing pin, the improvement which comprises;
a friction bearing surface formed on said steel bearing pin and having a carburized case of a depth of at least 0.030 inch;
a boronized surface having a depth of at least 0.001
inch formed on said carburized case;
said carburized surface being hardened I and tempered by heat treatment;
whereby the wear resistant boronized surface has a tough and strong supporting base to sustain large loads imposed by a mating friction bearing in said rotatable cutter and avoid brittle fracture.
3. In an earth boring drill bit having at least one rotatable cutter supported on a steel bearing pin, the improvement which comprises:
a carburized friction bearing surface formedon said steel bearing pin;
a boronized surface formed on said carburized bearing surface;
said carburized case being quenched from a temperature to produce a martensitic grain structure;
said carburized case being tempered to produce a tempered martensitic grain structure;
whereby the wear resistantboronized surface hasa tough and strong supporting base to sustain large loads imposed by a mating friction bearing in said rotatable cutter and avoid brittle fracture.
4. In an earth boring drill bit having at least one rotatable cutter supported on a steel bearing pin, the improvement which comprises:
a friction bearing surface formed on said steel bearing pin and having a carburized case of a depth of at least 0.030 inch;
a boronized surface having a depth of at least 0.001
inch formed on said carburized case;
said carburized case being quenched from a temperature to produce a martensitic grain structure;
said carburized case being tempered to produce a tempered martensitic grain structure;
whereby the wear resistant boronized surface has a tough and strong supporting base to sustain large loads imposed by a mating friction bearing in said rotatable cutter and avoid brittle fracture.
5. In an earth boring drill bit having at least one rotatable cutter supported on a steel bearing pin, the improvement which comprises:
a friction bearing surface formed on said steel bearing pin and having a carburized case of a depth of at least 0.030 inch;
a boronized surface having a depth of at least 0.001
inch formed on said carburized case;
said carburized case being quenched from a temperature of at least 1390F. to produce a martensitic grain structure;
said carburized case being tempered from a temperature within a range of 290 through 510F. for about 1 hour to produce a tempered martinsitic grain structure;
whereby the wear resistant boronized surface has a tough and strong supporting base to sustain large loads imposed by a mating friction bearing in said rotatable cutter and avoid brittle fracture.
6. The method of manufacturing earth boring drill bits having at least one rotatable cutter supported on a steel bearing pin, said method comprising the steps of:
forming a friction bearing surface on said bearing pin to produce a carburized case of selected depth;
boronizing said carburized case;
hardening said carburized case;
tempering said carburized case;
whereby the wear resistant boronized surface has a tough and strong supporting base to sustain large loads and avoid brittle fracture.
7. The method of claim 11 wherein said carburizing is to a depth of at least 0.030 inch and said boronizing is to a depth of at least 0.001 inch.
8. The method of claim 12 wherein said hardening is by quenching from a temperature of at least l390F., and said tempering is from a temperature within a range of 290 through 510F. for about 1 hour.
UNITED STATES PATENT OFFICE @THHCATE OF CORECHN Patent No. 3,922,038 Dated November 25, 1975 Inventor(s) Stanley R. Scales It is certified that error appears in the above-identified patent and that said Letters Patent are hereby Corrected as shown below:
Claim 7, Col. 6, line 16, "11" is changed to --6---; Claim 8, Col. 6, line l9, "12'' is changed to --7--..
Signed and Scaled this Twentieth Day Of July 1976 [SEAL] Attest:
RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner ofParents and Trademarks

Claims (8)

1. IN AN EARTH BORING DRILL BIT HAVING AT LEAST ONE ROTATABLE CUTTER SUPPORTED ON A STEEL BEARING PIN, THE IMPROVEMENT WHICH COMPRISES A CARBURIZED FRICTION BEARING SURFACE FORMED ON SAID STEEL BEARING PIN; A BORONIZED SURFACE FORMED ON SAID CARBURIZED BEARING SURFACE; SAID CARBURIZED SURFACE BEING HARDENED AND TEMPERED BY HEAT TREATMENT; WHEREBY THE WEAR RESISTANT BORONIZED SURFACE HAS A TOUGH AND STRONG SUPPORTING BASE TO SUSTAIN LARGE LOADS IMPOSED BY A MATING FRICTION BEARING IN SAID ROTATABLE CUTTER AND AVOID BRITTLE FRACTURE.
2. In an earth boring drill bit having at least one rotatable cutter supported on a steel bearing pin, the improvement which comprises: a friction bearing surface formed on said steel bearing pin and having a carburized case of a depth of at least 0.030 inch; a boronized surface having a depth of at least 0.001 inch formed on said carburized case; said carburized surface being hardened and tempered by heat treatment; whereby the wear resistant boronized surface has a tough and strong supporting base to sustain large loads imposed by a mating friction bearing in said rotatable cutter and avoid brittle fracture.
3. In an earth boring drill bit having at least one rotatable cutter supported on a steel bearing pin, the improvement which comprises: a carburized friction bearing surface formed on said steel bearing pin; a boronized surface formed on said carburized bearing surface; said carburized case being quenched from a temperature to produce a martensitic grain structure; said carburized case being tempered to produce a tempered martensitic grain structure; whereby the wear resistant boronized surface has a tough and strong supporting base to sustain large loads imposed by a mating friction bearing in said rotatable cutter and avoid brittle fracture.
4. In an earth boring drill bit having at least one rotatable cutter supported on a steel bearing pin, the improvement which comprises: a friction bearing surface formed on said steel bearing pin and having a carburized case of a depth of at least 0.030 inch; a boronized surface having a depth of at least 0.001 inch formed on said carburized case; said carburized case being quenched from a temperature to produce a martensitic grain structure; said carburized case being tempered to produce a tempered martensitic grain structure; whereby the wear resistant boronized surface has a tough and strong supporting base to sustain large loads imposed by a mating friction bearing in said rotatable cutter and avoid brittle fracture.
5. In an earth boring drill bit having at least one rotatable cutter supported on a steel bearing pin, the improvement which comprises: a friction bearing surface formed on said steel bearing pin and having a carburized case of a depth of at least 0.030 inch; a boronized surface having a depth of at least 0.001 inch formed on said carburized case; said carburized case being quenched from a temperature of at least 1390*F. to produce a martensitic grain structure; said carburized case being tempered from a temperature within a range of 290* through 510*F. for about 1 hour to produce a tempered martinsitic grain structure; whereby the wear resistant boronized surface has a tough and strong supporting base to sustain large loads imposed by a mating friction bearing in said rotatable cutter and avoid brittle fracture.
6. The method of manufacturing earth boring drill bits having at least one rotatable cutter supported on a steel bearing pin, said method comprising the steps of: forming a friction bearing surface on said bearing pin to produce a carburized case of selected depth; boronizing said carburized case; hardening said carburized case; tempering said carburized case; whereby the weaR resistant boronized surface has a tough and strong supporting base to sustain large loads and avoid brittle fracture.
7. The method of claim 11 wherein said carburizing is to a depth of at least 0.030 inch and said boronizing is to a depth of at least 0.001 inch.
8. The method of claim 12 wherein said hardening is by quenching from a temperature of at least 1390*F., and said tempering is from a temperature within a range of 290* through 510*F. for about 1 hour.
US387566A 1973-08-10 1973-08-10 Wear resistant boronized surfaces and boronizing methods Expired - Lifetime US3922038A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
US387566A US3922038A (en) 1973-08-10 1973-08-10 Wear resistant boronized surfaces and boronizing methods
CA194,785A CA1006869A (en) 1973-08-10 1974-03-12 Wear resistant boronized surfaces and boronizing methods
BR2519/74A BR7402519A (en) 1973-08-10 1974-03-29 IMPROVEMENTS IN THE PROCESS OF MANUFACTURING STEEL ITEMS IN DRILLING DRILLS IN THE MANUFACTURING PROCESS OF SUCH DRILLS AND IN STEEL ITEMS
AR253726A AR202648A1 (en) 1973-08-10 1974-05-14 A METHOD TO MANUFACTURE STEEL ARTICLES THAT REQUIRE A HARD AND TIGHT SURFACE, RESISTANT TO WEAR. AND THE STEEL ARTICLES SO OBTAINED
GB2208474A GB1435045A (en) 1973-08-10 1974-05-17 Wear resistant boronized surfaces and boronizing methods
SE7409633A SE397841B (en) 1973-08-10 1974-07-25 STEEL PRODUCT WITH A STRONG AND STRENGTH AGAINST NOTING RESISTANT SURFACE AND WAY TO PRODUCE SUCH A PRODUCT
IT26005/74A IT1017921B (en) 1973-08-10 1974-08-06 METALLIC ARTICLES WITH WEAR RESISTANT BORON SURFACES COLARLY PARTS FOR GEOLOGICAL DRILL BITS AND RELATED PROCESS DIMENSION OF MANUFACTURE
US05/616,537 US4012238A (en) 1973-08-10 1975-09-25 Method of finishing a steel article having a boronized and carburized case

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US387566A US3922038A (en) 1973-08-10 1973-08-10 Wear resistant boronized surfaces and boronizing methods

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US05/616,537 Continuation-In-Part US4012238A (en) 1973-08-10 1975-09-25 Method of finishing a steel article having a boronized and carburized case
US62292975A Division 1975-10-16 1975-10-16

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US3922038A true US3922038A (en) 1975-11-25

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AR (1) AR202648A1 (en)
BR (1) BR7402519A (en)
CA (1) CA1006869A (en)
GB (1) GB1435045A (en)
IT (1) IT1017921B (en)
SE (1) SE397841B (en)

Cited By (31)

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US4012238A (en) * 1973-08-10 1977-03-15 Hughes Tool Company Method of finishing a steel article having a boronized and carburized case
US4204437A (en) * 1978-04-03 1980-05-27 Smith International, Inc. Friction bearing rock bit and segment, and method for making them
US4251297A (en) * 1976-08-16 1981-02-17 Matsushita Electric Industrial Co., Ltd. Method for manufacturing magnetic head using boronizing treatment
US4495006A (en) * 1983-10-31 1985-01-22 Dresser Industries, Inc. Borocarburizing ferrous substrates
US4495005A (en) * 1983-10-31 1985-01-22 Dresser Industries, Inc. Carbosiliconizing ferrous substrates
US4540596A (en) * 1983-05-06 1985-09-10 Smith International, Inc. Method of producing thin, hard coating
US4600064A (en) * 1985-02-25 1986-07-15 Hughes Tool Company Earth boring bit with bearing sleeve
US4753303A (en) * 1983-10-17 1988-06-28 Hughes Tool Company--USA Earth boring bit with two piece bearing and rigid face seal assembly
US4934467A (en) * 1988-12-02 1990-06-19 Dresser Industries, Inc. Drill bit wear resistant surface for elastomeric seal
US4979998A (en) * 1989-10-10 1990-12-25 Union Carbide Corporation Process for forming a metal boride coating on a carbonaceous substrate
US5287936A (en) * 1992-01-31 1994-02-22 Baker Hughes Incorporated Rolling cone bit with shear cutting gage
US5346026A (en) * 1992-01-31 1994-09-13 Baker Hughes Incorporated Rolling cone bit with shear cutting gage
US5455068A (en) * 1994-04-28 1995-10-03 Aves, Jr.; William L. Method for treating continuous extended lengths of tubular member interiors
US5467836A (en) * 1992-01-31 1995-11-21 Baker Hughes Incorporated Fixed cutter bit with shear cutting gage
US5636700A (en) * 1995-01-03 1997-06-10 Dresser Industries, Inc. Roller cone rock bit having improved cutter gauge face surface compacts and a method of construction
US5709278A (en) * 1996-01-22 1998-01-20 Dresser Industries, Inc. Rotary cone drill bit with contoured inserts and compacts
US5722497A (en) * 1996-03-21 1998-03-03 Dresser Industries, Inc. Roller cone gage surface cutting elements with multiple ultra hard cutting surfaces
US5755299A (en) * 1995-08-03 1998-05-26 Dresser Industries, Inc. Hardfacing with coated diamond particles
US5836409A (en) * 1994-09-07 1998-11-17 Vail, Iii; William Banning Monolithic self sharpening rotary drill bit having tungsten carbide rods cast in steel alloys
US6102140A (en) * 1998-01-16 2000-08-15 Dresser Industries, Inc. Inserts and compacts having coated or encrusted diamond particles
US6138779A (en) * 1998-01-16 2000-10-31 Dresser Industries, Inc. Hardfacing having coated ceramic particles or coated particles of other hard materials placed on a rotary cone cutter
US6170583B1 (en) 1998-01-16 2001-01-09 Dresser Industries, Inc. Inserts and compacts having coated or encrusted cubic boron nitride particles
US6196338B1 (en) * 1998-01-23 2001-03-06 Smith International, Inc. Hardfacing rock bit cones for erosion protection
US6478887B1 (en) * 1998-12-16 2002-11-12 Smith International, Inc. Boronized wear-resistant materials and methods thereof
US6547017B1 (en) 1994-09-07 2003-04-15 Smart Drilling And Completion, Inc. Rotary drill bit compensating for changes in hardness of geological formations
US20050087370A1 (en) * 2003-10-22 2005-04-28 Ledgerwood Leroy W.Iii Increased projection for compacts of a rolling cone drill bit
US20080193298A1 (en) * 2007-02-14 2008-08-14 Hurst William D Treatment of turbine blades to increase hardness
US20110031026A1 (en) * 2009-08-07 2011-02-10 James Andy Oxford Earth-boring tools and components thereof including erosion resistant extensions, and methods of forming such tools and components
US20110132769A1 (en) * 2008-09-29 2011-06-09 Hurst William D Alloy Coating Apparatus and Metalliding Method
US8316679B2 (en) 2010-10-04 2012-11-27 Siemens Industry, Inc. Boronized laying pipe
WO2015058932A1 (en) * 2013-10-22 2015-04-30 Robert Bosch Gmbh Method for producing a locally boronized or chromized component

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Cited By (37)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4012238A (en) * 1973-08-10 1977-03-15 Hughes Tool Company Method of finishing a steel article having a boronized and carburized case
US4251297A (en) * 1976-08-16 1981-02-17 Matsushita Electric Industrial Co., Ltd. Method for manufacturing magnetic head using boronizing treatment
US4204437A (en) * 1978-04-03 1980-05-27 Smith International, Inc. Friction bearing rock bit and segment, and method for making them
US4540596A (en) * 1983-05-06 1985-09-10 Smith International, Inc. Method of producing thin, hard coating
US4753303A (en) * 1983-10-17 1988-06-28 Hughes Tool Company--USA Earth boring bit with two piece bearing and rigid face seal assembly
US4495006A (en) * 1983-10-31 1985-01-22 Dresser Industries, Inc. Borocarburizing ferrous substrates
US4495005A (en) * 1983-10-31 1985-01-22 Dresser Industries, Inc. Carbosiliconizing ferrous substrates
EP0193486A3 (en) * 1985-02-25 1988-01-07 Hughes Tool Company Earth boring bit with bearing sleeve
EP0193486A2 (en) * 1985-02-25 1986-09-03 Hughes Tool Company Earth boring bit with bearing sleeve
US4600064A (en) * 1985-02-25 1986-07-15 Hughes Tool Company Earth boring bit with bearing sleeve
US4934467A (en) * 1988-12-02 1990-06-19 Dresser Industries, Inc. Drill bit wear resistant surface for elastomeric seal
US4979998A (en) * 1989-10-10 1990-12-25 Union Carbide Corporation Process for forming a metal boride coating on a carbonaceous substrate
US5287936A (en) * 1992-01-31 1994-02-22 Baker Hughes Incorporated Rolling cone bit with shear cutting gage
US5346026A (en) * 1992-01-31 1994-09-13 Baker Hughes Incorporated Rolling cone bit with shear cutting gage
US5467836A (en) * 1992-01-31 1995-11-21 Baker Hughes Incorporated Fixed cutter bit with shear cutting gage
US5455068A (en) * 1994-04-28 1995-10-03 Aves, Jr.; William L. Method for treating continuous extended lengths of tubular member interiors
US6547017B1 (en) 1994-09-07 2003-04-15 Smart Drilling And Completion, Inc. Rotary drill bit compensating for changes in hardness of geological formations
US5836409A (en) * 1994-09-07 1998-11-17 Vail, Iii; William Banning Monolithic self sharpening rotary drill bit having tungsten carbide rods cast in steel alloys
US5636700A (en) * 1995-01-03 1997-06-10 Dresser Industries, Inc. Roller cone rock bit having improved cutter gauge face surface compacts and a method of construction
US5755299A (en) * 1995-08-03 1998-05-26 Dresser Industries, Inc. Hardfacing with coated diamond particles
US5755298A (en) * 1995-08-03 1998-05-26 Dresser Industries, Inc. Hardfacing with coated diamond particles
US5709278A (en) * 1996-01-22 1998-01-20 Dresser Industries, Inc. Rotary cone drill bit with contoured inserts and compacts
US5722497A (en) * 1996-03-21 1998-03-03 Dresser Industries, Inc. Roller cone gage surface cutting elements with multiple ultra hard cutting surfaces
US6102140A (en) * 1998-01-16 2000-08-15 Dresser Industries, Inc. Inserts and compacts having coated or encrusted diamond particles
US6170583B1 (en) 1998-01-16 2001-01-09 Dresser Industries, Inc. Inserts and compacts having coated or encrusted cubic boron nitride particles
US6138779A (en) * 1998-01-16 2000-10-31 Dresser Industries, Inc. Hardfacing having coated ceramic particles or coated particles of other hard materials placed on a rotary cone cutter
US6196338B1 (en) * 1998-01-23 2001-03-06 Smith International, Inc. Hardfacing rock bit cones for erosion protection
US6478887B1 (en) * 1998-12-16 2002-11-12 Smith International, Inc. Boronized wear-resistant materials and methods thereof
US20050087370A1 (en) * 2003-10-22 2005-04-28 Ledgerwood Leroy W.Iii Increased projection for compacts of a rolling cone drill bit
US7011170B2 (en) * 2003-10-22 2006-03-14 Baker Hughes Incorporated Increased projection for compacts of a rolling cone drill bit
US20080193298A1 (en) * 2007-02-14 2008-08-14 Hurst William D Treatment of turbine blades to increase hardness
US7931446B2 (en) 2007-02-14 2011-04-26 X-Treme Aerospace Inc. Treatment of turbine blades to increase hardness
US20110132769A1 (en) * 2008-09-29 2011-06-09 Hurst William D Alloy Coating Apparatus and Metalliding Method
US20110031026A1 (en) * 2009-08-07 2011-02-10 James Andy Oxford Earth-boring tools and components thereof including erosion resistant extensions, and methods of forming such tools and components
US8267203B2 (en) 2009-08-07 2012-09-18 Baker Hughes Incorporated Earth-boring tools and components thereof including erosion-resistant extensions, and methods of forming such tools and components
US8316679B2 (en) 2010-10-04 2012-11-27 Siemens Industry, Inc. Boronized laying pipe
WO2015058932A1 (en) * 2013-10-22 2015-04-30 Robert Bosch Gmbh Method for producing a locally boronized or chromized component

Also Published As

Publication number Publication date
BR7402519A (en) 1975-12-02
SE397841B (en) 1977-11-21
IT1017921B (en) 1977-08-10
AR202648A1 (en) 1975-06-30
CA1006869A (en) 1977-03-15
GB1435045A (en) 1976-05-12
SE7409633L (en) 1975-02-11

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