EP4306671A1 - Insert de forage de roches - Google Patents

Insert de forage de roches Download PDF

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Publication number
EP4306671A1
EP4306671A1 EP22184187.7A EP22184187A EP4306671A1 EP 4306671 A1 EP4306671 A1 EP 4306671A1 EP 22184187 A EP22184187 A EP 22184187A EP 4306671 A1 EP4306671 A1 EP 4306671A1
Authority
EP
European Patent Office
Prior art keywords
rock drill
insert
cemented carbide
drill insert
hardness
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP22184187.7A
Other languages
German (de)
English (en)
Inventor
Leif Åkesson
Krystof TURBA
Ida BORGH
Mirjam LILJA
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sandvik Mining and Construction Tools AB
Original Assignee
Sandvik Mining and Construction Tools AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sandvik Mining and Construction Tools AB filed Critical Sandvik Mining and Construction Tools AB
Priority to EP22184187.7A priority Critical patent/EP4306671A1/fr
Priority to PCT/EP2023/068336 priority patent/WO2024012930A1/fr
Publication of EP4306671A1 publication Critical patent/EP4306671A1/fr
Pending legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C29/00—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides
    • C22C29/02—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides
    • C22C29/06—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides based on carbides, but not containing other metal compounds
    • C22C29/08—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides based on carbides, but not containing other metal compounds based on tungsten carbide
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C29/00—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides
    • C22C29/005—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides comprising a particular metallic binder
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
    • B22F2005/001—Cutting tools, earth boring or grinding tool other than table ware
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
    • B22F2998/10—Processes characterised by the sequence of their steps
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/12—Both compacting and sintering
    • B22F3/14—Both compacting and sintering simultaneously
    • B22F3/15—Hot isostatic pressing
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C2202/00—Physical properties
    • C22C2202/02—Magnetic

Definitions

  • the present invention relates to a rock drill insert comprising chromium alloyed cemented carbide having a low carbon content.
  • Rock drilling is a technical area in which the inserts which are used for the purpose of drilling in the rock are subjected to high stresses, repeated impacts and severe corrosive conditions due to the inherent nature of the drilling. Different drilling techniques will generate different loads on the inserts, resulting from a combination of contact stress, impacts, shear and bending. Particularly severe stress conditions are found in applications such as those in which the rock drill inserts are mounted in a rock drill bit body of a top-hammer (TH) device, a down-the-hole (DTH) drilling device or a rotary drilling device, a raise boring device or a mechanical cutting device.
  • TH top-hammer
  • DTH down-the-hole
  • rock drill inserts may consist of a body made of cemented carbide that comprises hard constituents such as tungsten carbide (WC) in a binder phase such as cobalt (Co). It is desirable to increase the lifetime of the inserts.
  • WO2018/060125 discloses that by adding chromium to the cemented carbide, the performance of the drill bits is enhanced. There is however the need to further improve the performance and lifetime of the inserts, especially in hard rock drilling applications.
  • the problem to be solved is how to further increase the lifetime of the drill inserts.
  • body is herein meant the cemented carbide of the innermost part (centre) of the rock drill insert.
  • both of these properties are enhanced simultaneously, which leads to the reduction of the risk of premature insert breakages in the rock drilling application.
  • the enhanced plasticity and strain hardening in compression allow for an optimally enhanced level of induced residual stresses in the material, which further increase the resistance of the insert to premature breakage and thus extend the insert lifetime.
  • the strain hardening and induced residual compressive stresses are also manifested in an apparent hardness increase at and below the surface of the insert.
  • the cobalt content is between 8 - 18 wt%.
  • this range facilitates obtaining high fracture toughness in the material, thus making it suitable especially for toughness-focused rock drilling applications such as rotary drill bits, raise boring pilot bits, and raise boring cutters.
  • the cobalt content is between 4 - 8 wt%.
  • this range makes it possible to reach particularly high wear resistance, typically required in applications such as top hammer and down the hole drilling.
  • the corrected CoM / wt% Co is between 0.73 - 0.79.
  • this range results in the most optimal enhancement of the material's strain hardening capacity and its plasticity in compression.
  • the difference between an average hardness at 0.3 mm below the surface of the rock drill insert and an average hardness in the bulk of the rock drill insert is at least 30 HV3 wherein hardness is measured according to ISO EN6507.
  • the hardness difference results from mechanically induced compressive residual stresses and strain hardening of the binder phase.
  • this leads to an increased strength and apparent toughness of the rock drill insert, reducing the risk of early damage and failure of the insert and consequently increasing the insert lifetime.
  • the difference between the hardness at any point 0.3 mm below the surface of the rock drill insert and the hardness at 1 mm below the surface of the rock drill insert is at least 20 HV3 wherein hardness is measured according to ISO EN6507.
  • the hardness difference reflects the induced compressive residual stresses and strain hardening of the binder phase, leading to enhanced apparent toughness and strength of the insert, consequently increasing its lifetime during drilling.
  • the WC grain size mean value of the cemented carbide is above 1 ⁇ m but less than 18 ⁇ m as measured according to Jeffries method defined in the description hereinbelow.
  • this grain sizes provides the optimal balance between wear resistance and toughness for rock tool applications.
  • the mean WC grain size value of the cemented carbide is above 1.5 ⁇ m but less than 10 ⁇ m.
  • these grain sizes provide the optimal balance between wear resistance and toughness for rock tool applications.
  • the mass ratio Cr/Co in the cemented carbide is between 0.075-0.15.
  • this provides optimum wear resistance and capacity for strain hardening.
  • the mass ratio Cr/Co in the cemented carbide is between 0.05 - 0.12.
  • this provides the optimum balance between plasticity, capacity for strain hardening, wear resistance, and fracture toughness.
  • the cemented carbide has a bulk hardness of not higher than 1700 HV3.
  • rock drill bit body comprising one or more mounted rock drill inserts as described hereinbefore or hereinafter.
  • magnetic-% Co is the weight percentage of magnetic Co and wt-% Co and wt-% Cr are the weight percentage of Co and Cr in the cemented carbide, respectively.
  • This specific range of corrected CoM / wt% Co is achieved by careful control of the carbon content.
  • the corrected CoM / wt% Co of a sintered sample is measured and calculated by using commercially available Foerster Koerzimat CS 1.096 equipment. The sample is weighed and then put into the magnetic coil as described in the Koerzimat CS 1.096 V3.09 manual. The magnetic moment is measured and from that the weight-specific saturation magnetization, ⁇ s, is calculated from the ratio of magnetic moment to weight of the sample. Then the proportion of magnetic material in % (known as magnetic-% Co) is calculated by dividing ⁇ s with the material constant for Co, which is 2010 10 -7 Tm 3 /kg.
  • the rock drill insert 2 of the present invention is produced by means of a process in which a powder comprising the elements of the cemented carbide is milled and compacted into a compact which is then sintered.
  • a grinding step to obtain the precise dimension of the drill insert is generally made.
  • a drill insert of the present invention generally has a cylindrical base part and a rounded top which may be hemispherical, conical or asymmetric. It should be understood that the rock drill insert could have alternative geometries to that shown in figure 1 .
  • the curved surface of the cylindrical base part is ground to obtain the precise diameter wanted, while the surfaces of the top part and the circular base part are kept in their as sintered state.
  • the drill insert is then subjected to mechanical posttreatment which introduces high levels of compressive stresses in the insert, such as high energy tumbling.
  • the binder phase content of the cemented carbide is substantially equal throughout the rock drill insert, i.e., no substantial gradient of Co content is present when going from the surface of the rock drill insert to its interior.
  • the cobalt content is preferably between 5- 16 wt%.
  • the cobalt content is between 8 - 18 wt%, preferably between 10 - 16 wt%.
  • the cobalt content is between 4 - 10 wt%, preferably between 4 - 8 wt%.
  • the corrected CoM / wt% Co is between 0.72 - 0.81, preferably between 0.73 - 0.79, more preferably between 0.74 - 0.78.
  • the difference between an average hardness at 0.3 mm below the surface of the rock drill insert and an average hardness in the bulk of the rock drill insert is at least 30 HV3, preferably at least 35 HV3, more preferably at least 40 HV3, even more preferably at least 40 HV3, even more preferably at least 50 HV3, even more preferably at least 60 HV3, wherein hardness is measured according to ISO EN6507.
  • the difference between the hardness at any point 0.3 mm below the surface of the rock drill insert and the hardness at 1 mm below the surface of the rock drill insert is at least 20 HV3, preferably at least 35 HV3, more preferably at least 40 HV3, more preferably at least 45 HV3 wherein hardness is measured according to ISO EN6507.
  • the average hardness at a certain depth from the surface is defined as the average of at least 50 measured hardness values at that depth evenly distributed around the insert.
  • the mean value of the cemented carbide grain size is above 1 ⁇ m but less than 18 ⁇ m as measured according to Jeffries method defined in the description.
  • the WC grain size is chosen to suit the desired end properties of the cemented carbide in terms of, for example, toughness, strength, wear resistance and thermal conductivity.
  • the WC mean grain size is above 1 ⁇ m, or above 1.25 ⁇ m, or above 1.5 ⁇ m, or above 1.75 ⁇ m, or above 2.0 ⁇ m. If the WC grain size is too large, the material becomes difficult to sinter. Therefore, it is preferred that the WC mean grain size is less than 18 ⁇ m, or less than 15 ⁇ m, or less than 10 ⁇ m, or less than 6 ⁇ m.
  • the micrographs for WC grain size evaluation were obtained using a scanning electron microscope (SEM) in backscatter electron (BSE) contrast. Prior to the imaging, the material samples were polished using standard procedures and etched with Murakami solution to generate contrast at grain boundaries.
  • the mean WC grain size was then evaluated using the Jeffries method described below, from at least two different micrographs for each material. An average value was then calculated from the mean grain size values obtained from the individual micrographs (for each material respectively).
  • the procedure for the mean grain size evaluation using a modified Jeffries method was the following: A rectangular frame of suitable size is selected within the SEM micrograph so as to contain a minimum of 300 WC grains.
  • Equation 3 is used to estimate the WC fraction based on the known Co content in the material. Equation 4 then yields the mean WC grain size from the ratio of the total WC area in the frame to the number of grains contained in it. Equation 4 also contains a correction factor compensating for the fact that in a random 2D section, not all grains will be sectioned through their maximum diameter.
  • the mass ratio Cr/Co in the cemented carbide is between 0.075 - 0.15, more preferably between 0.85 - 0.12.
  • the mass ratio Cr/Co in the cemented carbide is between 0.05 - 0.12, preferably between 0.05 - 0.10.
  • the M 7 C 3 phase is present in the cemented carbide, where M designates a combination of Cr, Co and W, i.e. (Cr,Co,W) 7 C 3 .
  • the Co solubility can reach as high as 38 at. % of the metallic content in the M 7 C 3 carbide.
  • the balance of Cr:Co:W is influenced by the overall carbon content in the cemented carbide.
  • cemented carbide has a bulk hardness of not higher than 1700 HV3, preferably not higher than 1650 HV3, more preferably not higher than 1600 HV3.
  • the cemented carbide of the rock drill insert has suitably a hardness of the bulk of at least 800 HV3, or at least 900 HV3, or at least 1000 HV3.
  • rock drill inserts 2 are mounted in a rock drill bit body of a top-hammer (TH) device or a down-the-hole (DTH) drilling device or a rotary drilling device or a raise boring pilot bit device or a raise boring cutter device or a push boring (blind boring) device or a mechanical cutting device or a horizontal directional drilling (HDD) device.
  • the rotary drilling device may be an oil and gas rotary cutter device.
  • Table 1 Sample summary Sample Co content (wt%) Cr content (wt%) Cr / Co mass ratio HV20 in bulk Average grain size ( ⁇ m) Corrected CoM / wt% Co A (comparison) 11.0 1.1 0.10 1099 4.92 0.88 B (invention) 11.0 1.1 0.10 1092 4.31 0.78 C (comparison) 13.5 1.35 0.10 1095 3.74 0.87 D (invention) 13.5 1.35 0.10 1059 3.76 0.74
  • Samples A-D were strained at room temperature in uniaxial compression until fracture using an Instron 5989 test frame, at a constant rate of crosshead displacement equal to 0.6 mm / min, while recording load-displacement curves.
  • the test fixture, the hardness and parallelism of the counter surfaces, as well as the sample geometry were in accordance with the ISO 4506:2017 E standard "Hardmetals - Compression test”.
  • Engineering stress was calculated from the load values by dividing the load with the initial minimum cross-sectional area, obtained from the minimum diameter measured on each individual test sample prior to testing.
  • Elastic deformation of the samples was subtracted from the stress - displacement curves during test data post-processing using linear regression, in order to isolate only the plastic deformation of the materials. This isolation of the plastic deformation from the stress - displacement curves
  • Figure 2 compares the deformation curves in uniaxial compression for samples A and B, i.e. the samples having 11 wt% Co.
  • Sample A comparative sample
  • sample B comparative sample
  • Figure 3 compares the deformation curves in uniaxial compression for samples C and D, i.e. the samples having 13.5 wt% Co.
  • Sample C comparative sample
  • sample D comparative sample
  • inventive samples both show a more pronounced strain hardening, i.e. a steeper deformation curve, throughout most of the deformation until failure; higher ultimate compressive strength (UCS) and substantially greater plasticity (plastic deformation to failure) as compared to the comparative sample.
  • Figure 3 shows that this effect is present also when the samples have equal mean tungsten carbide grain size, in addition to having equal binder phase content.
  • Rock drill bit inserts with a 10 mm outer diameter and a hemispherical top geometry were produced out of all four materials (A,B,C,D) and in their as ground state subjected to wear testing using a rotating granite log counter surface with continual water flow aimed at the insert / rock contact.
  • the insert / rock contact was maintained by applying a constant force of 10 kgf (98 N). Since the inserts were ground only on their cylindrical section, the part of the insert in contact with the rock surface was in all cases in the as sintered state.
  • the granite log was rotating, the insert was moved along it with a constant feed rate of 0.9 mm / s, resulting in a total sliding distance between 432 and 446 m.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Earth Drilling (AREA)
EP22184187.7A 2022-07-11 2022-07-11 Insert de forage de roches Pending EP4306671A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP22184187.7A EP4306671A1 (fr) 2022-07-11 2022-07-11 Insert de forage de roches
PCT/EP2023/068336 WO2024012930A1 (fr) 2022-07-11 2023-07-04 Insert de perforatrice de roches

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP22184187.7A EP4306671A1 (fr) 2022-07-11 2022-07-11 Insert de forage de roches

Publications (1)

Publication Number Publication Date
EP4306671A1 true EP4306671A1 (fr) 2024-01-17

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Family Applications (1)

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EP22184187.7A Pending EP4306671A1 (fr) 2022-07-11 2022-07-11 Insert de forage de roches

Country Status (2)

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EP (1) EP4306671A1 (fr)
WO (1) WO2024012930A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2011890A1 (fr) * 2007-06-01 2009-01-07 Sandvik Intellectual Property AB Carbure cimenté à grains fins ayant une structure affinée
WO2018060125A1 (fr) 2016-09-28 2018-04-05 Sandvik Intellectual Property Ab Organe de perçage de roche
EP3763840A1 (fr) * 2019-07-10 2021-01-13 Sandvik Mining and Construction Tools AB Corps de carbure cémenté à gradient et son procédé de fabrication

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2011890A1 (fr) * 2007-06-01 2009-01-07 Sandvik Intellectual Property AB Carbure cimenté à grains fins ayant une structure affinée
WO2018060125A1 (fr) 2016-09-28 2018-04-05 Sandvik Intellectual Property Ab Organe de perçage de roche
EP3808867A1 (fr) * 2016-09-28 2021-04-21 Sandvik Intellectual Property AB Pièce rapportée de perforatrice de roches
EP3763840A1 (fr) * 2019-07-10 2021-01-13 Sandvik Mining and Construction Tools AB Corps de carbure cémenté à gradient et son procédé de fabrication

Also Published As

Publication number Publication date
WO2024012930A1 (fr) 2024-01-18

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