Reciprocating saw blade having teeth formed of sintered ceramic material welded to saw blade body

Abstract

Embodiments of the present disclosure relate to a reciprocating saw blade. A reciprocating saw blade includes a body having a first end, a second end spatially spaced from the first end, a ridge edge, and a cutting edge opposite the ridge edge. The reciprocating saw blade also includes a plurality of teeth defining a cutting portion of the cutting edge. Each tooth of the plurality of teeth includes a base having an integral configuration with the body. The base is made of a first material having a first hardness. The tip is welded to the base, and the tip is made of a sintered ceramic material having a second hardness greater than the first hardness. The sintered ceramic material includes tungsten carbide particles and other particles containing one or more cubic carbides. The hardness of the sintered ceramic material is at least 1000 HV10.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of and priority to U.S. Application No. 63 / 374,303, filed on September 1, 2022, the entire contents of which are incorporated herein by reference. Background Art

[0003] The present invention relates to carbide tips for teeth of saw blades, and more particularly to saw blades for use with power tools.

[0004] Saw blades, such as reciprocating saw blades, are used to cut wood, metal, plastic, and other materials. Saw blades generally include a body, one or more attachment portions, and a cutting portion. The cutting portion includes a plurality of teeth that scrape back and forth on a workpiece to cut through the material. Due to the significant stress associated with the cutting action, the teeth of a reciprocating saw blade are susceptible to wear. The wear life of a saw blade can be improved by using harder and / or tougher materials for the teeth. Additionally or alternatively, the teeth can be coated to improve the wear life. However, these improvements are balanced against the cost and feasibility of manufacturing the saw blade using the improved materials. Summary of the invention

[0005] According to one aspect, an embodiment of the present disclosure relates to a reciprocating saw blade. The reciprocating saw blade includes a body having a first end, a second end spaced apart from the first end, a ridge edge extending between the first end and the second end, and a cutting edge extending between the first end and the second end. The cutting edge is opposite to the ridge edge. The reciprocating saw blade also includes a plurality of teeth defining a cutting portion of the cutting edge. Each of the plurality of teeth includes a base having an integral structure with the body. The base is made of a first material having a first hardness. The tip is welded to the base, and the tip is made of a sintered ceramic material having a second hardness. The second hardness is greater than the first hardness. The sintered ceramic material includes tungsten carbide particles and other ceramic particles held together by a metal matrix material. The other ceramic particles are made of at least one ceramic material having a hardness of at least 1500 HV10 and a thermal conductivity of 50 W / mK or less.

[0006] According to another aspect, an embodiment of the present disclosure relates to a reciprocating saw blade. The reciprocating saw blade includes a body having a first end, a second end spaced apart from the first end, a ridge edge extending between the first end and the second end, and a cutting edge extending between the first end and the second end. The cutting edge is opposite to the ridge edge. The reciprocating saw blade also includes a plurality of teeth defining a cutting portion of the cutting edge. Each of the plurality of teeth includes a base having an integral structure with the body. The base is made of a first material having a first hardness. The tip is welded to the base, and the tip is made of a sintered ceramic material having a second hardness. The second hardness is greater than the first hardness. The sintered ceramic material includes tungsten carbide particles and other particles containing one or more cubic carbides. The tungsten carbide particles and other particles are held together by a metal matrix material. The sintered ceramic material includes at least 3 weight % of other particles containing one or more cubic carbides.

[0007] According to yet another aspect, an embodiment of the present disclosure relates to a reciprocating saw blade. The reciprocating saw blade includes a body having a first end, a second end spaced apart from the first end, a ridge edge extending between the first end and the second end, and a cutting edge extending between the first end and the second end. The cutting edge is opposite to the ridge edge. The reciprocating saw blade also includes a plurality of teeth defining a cutting portion of the cutting edge. Each of the plurality of teeth includes a base having an integral structure with the body. The base is made of a first material having a first hardness. The tip is welded to the base, and the tip is made of a sintered ceramic material having a second hardness. The second hardness is greater than the first hardness. The sintered ceramic material includes tungsten carbide particles and other particles containing one or more ceramic materials. The tungsten carbide particles and the other particles are held together by a metal matrix material. The hardness of the sintered ceramic material at room temperature is at least 1000 HV10.

[0008] According to another aspect, an embodiment of the present disclosure relates to a cutting tool. The cutting tool includes a body having a cutting edge. The cutting tool also includes a plurality of teeth that define a cutting portion of the cutting edge. The plurality of teeth include at least four teeth per inch. Each of the plurality of teeth includes a base having an integral structure with the body. The base is made of a first material having a first hardness. The tip is welded to the base, and the tip is made of a sintered ceramic material having a second hardness. The second hardness is greater than the first hardness. The sintered ceramic material includes tungsten carbide particles and other particles containing one or more ceramic materials. The tungsten carbide particles and the other particles are held together by a metal matrix material. The hardness of the sintered ceramic material at room temperature is at least 1000 HV10.

[0009] According to yet another aspect, an embodiment of the present disclosure relates to a method of attaching a tip made of a sintered ceramic material to the body of a reciprocating saw blade to form a plurality of teeth. In the method, an insert of sintered ceramic material is pressed against the respective bases of the plurality of teeth. The bases are of integral construction with the body of the reciprocating saw blade. The insert is welded to the respective bases of the plurality of teeth. The plurality of teeth are ground to form the tip from the insert. The sintered ceramic material includes tungsten carbide particles and other particles containing one or more cubic carbides. The tungsten carbide particles and the other particles are held together by a metal matrix material. The sintered ceramic material includes at least 3 weight percent of one or more cubic carbides.

[0010] Additional features and advantages will be set forth in the detailed description which follows, and in part will become apparent to those skilled in the art from the specification or may be learned by practicing the embodiments as described in the written description and claims hereof as well as the accompanying drawings.

[0011] It is to be understood that both the foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework to understand the nature and character of the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings are included to provide a further understanding and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiments and together with the description serve to explain principles and operations of the various embodiments.

[0013] Figure 1 depicts a reciprocating saw blade and associated reciprocating saw according to an exemplary embodiment;

[0014] Figure 2 Depicted is a schematic diagram of an exemplary embodiment of the present invention. Figure 1 The reciprocating saw shown;

[0015] Figure 3 Depicted is a schematic diagram of an exemplary embodiment of the present invention. Figure 2 Detailed view of the cutting portion of a reciprocating saw;

[0016] Figure 4 Depicted is a schematic diagram of an exemplary embodiment of the present invention. Figure 3 Detailed view of the cutting teeth of the cutting portion;

[0017] Figure 5 depicts a flow chart of a method for attaching a sintered ceramic tip to a tooth of a reciprocating saw, the method including the optional steps of edge pretreatment and thin film coating, according to an exemplary embodiment;

[0018] Figure 6depicts a thin film ceramic coating on a tip of a cutting tooth according to an exemplary embodiment;

[0019] Figure 7 depicts another reciprocating saw blade according to another exemplary embodiment;

[0020] Figure 8 depicts an embodiment of an oscillating saw blade that may include teeth formed from a sintered ceramic material according to an exemplary embodiment; and

[0021] Fig. 9 Embodiments of a hole saw that may include teeth formed from a sintered ceramic material are depicted in accordance with exemplary embodiments. DETAILED DESCRIPTION

[0022] Referring generally to the accompanying drawings and to the following discussion, various embodiments of reciprocating saw blades having teeth with welded sintered ceramic tips are disclosed herein. As will be described more fully below, the sintered ceramic tip is formed of tungsten carbide particles and other ceramic particles, particularly cubic carbides having high hardness at operating temperatures. Tungsten carbide is used in sintered carbide applications because of its high room temperature hardness, excellent wear resistance, and ability to be welded to a steel saw blade body. However, other ceramic materials, such as cubic carbides, have higher hardness at operating temperatures. To date, the use of these materials in various applications has been limited by their low thermal conductivity, which increases the difficulty of attaching these materials to the saw blade body. Instead of welding, sintered carbides, including cubic carbides, are conventionally brazed to the saw blade body or mechanically fastened to the cutting tool. However, in applications where the saw blade body has many small joints, such as in a reciprocating saw blade, brazing is neither economical nor feasible. In addition, the small size of the teeth and the thinness of the blade make mechanical fastening impractical. Low thermal conductivity will also result in a mismatch in thermal expansion characteristics within each tooth and between the teeth and the blade body.

[0023] Cubic carbides have not been incorporated into reciprocating saw blades or other similar saw blades having many small joint joints, such as hole saws and oscillating saw blades, due to reduced weldability and because brazing and mechanical fastening are not feasible. Despite the expected joining difficulties using cubic carbides in these specific applications, the inventors surprisingly and unexpectedly discovered that teeth formed from a sintered ceramic material including tungsten carbide and cubic carbide can be satisfactorily and economically welded to the saw blade body of a reciprocating saw blade. Reciprocating saw blades having teeth with tips formed from such sintered ceramic materials have been shown to exhibit higher hardness at operating temperatures, increased wear life, and faster cutting during the life of the saw blade. These and other aspects and advantages of the welded sintered ceramic tips of the teeth of a reciprocating saw blade will be discussed in conjunction with the embodiments provided below and shown in the accompanying drawings. These embodiments are presented by way of illustration and not limitation.

[0024] Embodiments of the present disclosure are directed to a reciprocating saw blade 10 for use with a reciprocating saw 12 . Figure 1 Embodiments of a reciprocating saw 12 are illustrated that include an embodiment of a reciprocating saw blade 10 according to the present disclosure. In one or more embodiments, the reciprocating saw blade 10 is configured to be reversibly coupled to the reciprocating saw 12. For example, the reciprocating saw 12 can be used with a variety of different reciprocating saw blades 10, such as reciprocating saw blades 10 configured to cut through different materials. Additionally, as the reciprocating saw blade 10 wears, the worn reciprocating saw blade can be replaced with a new reciprocating saw blade 10. In one or more embodiments, the reciprocating saw 12 is a power tool configured to operate using a power source, such as a battery or a power cord.

[0025] Figure 2 An embodiment of a reciprocating saw blade 10 according to the present disclosure is illustrated. The reciprocating saw blade 10 includes a body 14 having a first end 16 and a second end 18. The first end 16 is spaced apart from the second end 18 along a longitudinal axis 20 of the reciprocating saw blade 10. In one or more embodiments, the first end 16 includes an attachment portion 22 coupled to the body 14. In one or more such embodiments, the attachment portion 22 includes a connector for coupling the reciprocating saw blade 10 to a reciprocating saw 12 (e.g., Figure 1 1 and 12. The attachment portion 22 may include a tang 24 and an aperture 26 for coupling the reciprocating saw blade 10 to the reciprocating saw 12. In one or more other such embodiments, the attachment portion 22 may include other suitable structures for coupling the reciprocating saw blade 10 to the reciprocating saw 12. In one or more embodiments, the body 14 of the reciprocating saw blade 10 is formed, for example, from a coil via stamping, laser cutting, grinding, etc. In one or more embodiments, the body 14 of the reciprocating saw blade 10 is formed from a steel alloy. In one or more embodiments, the steel alloy for the body 14 may be selected from a variety of suitable steel alloys ranging from relatively inexpensive AISI 1018 steel to relatively more expensive D6a HSS. A specific example of a steel alloy that can be used for the body 14 is AISI 6150, which has a hardness in the range of 40HRC to 55HRC (Rockwell C hardness).

[0026] The reciprocating saw blade 10 includes a ridge edge 28 and a cutting edge 30, wherein the cutting edge 30 is opposite the ridge edge 28. The ridge edge 28 and the cutting edge 30 each extend between the first end 16 and the second end 18. The cutting edge 30 includes a cutting portion 32 that includes a plurality of cutting teeth 34. In one or more embodiments, the cutting teeth 34 form a linear cutting edge 30 on the body 14. In one or more other embodiments, the cutting edge 30 is non-linear (e.g., curved, angled, discontinuous, etc.).

[0027] Including Figure 2 In one or more embodiments, including the illustrated embodiment, each tooth 34 generally has the same shape and size. In one or more other embodiments, the shape and / or size of the teeth 34 may vary along the length of the cutting portion 32. Figure 3 As shown, each tooth 34 includes a point 36, a rake face 38, and a relief face 40. In addition, the cutting teeth 34 are separated from each other by a plurality of tooth grooves 42. In one or more embodiments, the points 36 of the cutting teeth 34 define a longitudinal axis 20 (eg, Figure 2 4. The tooth 34 is formed of a plurality of teeth 36 and a plurality of teeth 38. The teeth 34 are each formed of a plurality of teeth 36 and a plurality of teeth 38. The teeth 34 are each formed of a plurality of teeth 36 and a plurality of teeth 38. The teeth 34 are each formed of a plurality of teeth 34 and a plurality of teeth 38. The teeth 34 are each formed of a plurality of teeth 34 and a plurality of teeth 34 ...

[0028] Reference Figure 4 , each tooth 34 is spaced apart from adjacent teeth 34 by a pitch P. The pitch P is measured between points 36 of adjacent teeth 34. In one or more embodiments, including the illustrated embodiment, the pitch P of the cutting teeth 34 is approximately the same along the length of the cutting portion 32. In one or more other embodiments, the pitch P varies between adjacent teeth 34. In one or more embodiments, the pitch P is such that the cutting portion 32 includes five teeth per inch (TPI), i.e., adjacent cutting teeth 50 are separated by a pitch P of 0.2 inches. In one or more other embodiments, the cutting portion 32 may include fewer or more teeth per inch. For example, the cutting portion 32 may include 4 teeth per inch, 6 teeth per inch, etc.

[0029] In one or more embodiments, the saw blade body 14 of the reciprocating saw blade 10 is made of a first material (e.g., low carbon steel, high speed steel, tool steel, or high strength low alloy steel), and each cutting tooth 34 is partially made of a first material having a first hardness and partially made of a second material having a second hardness greater than the first hardness. Figure 4As shown, each cutting tooth 34 includes a base 44 and a tip 46. The base 44 and the tip 46 together partially form the rake face 38 and the relief face 40 of the tooth 34, and the tip 46 forms the point 36 of the tooth 34. In one or more embodiments, the base 44 is integrally constructed with the saw blade body 14 and is composed of a first material, and the tip 46 is formed by an insert of a second material joined to the base 44. In one or more embodiments, the base 44 includes a first mating surface 48, and the tip 46 includes a second mating surface 50 configured to engage with the first mating surface 48. In the embodiment including Figure 4 In one or more embodiments, including the depicted embodiment, the first mating surface 48 is concave and the second mating surface 50 is convex. As will be discussed more fully below, the insert forming the tip 46 is positioned near the base 44 and welded together. Thereafter, the insert is machined to form the cutting surface of the tooth 34.

[0030] According to the present disclosure, the second material forming the tip 46 of the tooth 34 is a sintered ceramic comprising tungsten carbide particles and various other hard ceramic particles in a metal matrix. In particular, the sintered ceramic comprises tungsten carbide in an amount of at least 50 wt %, in particular 50 wt % to 80 wt %.

[0031] In one or more embodiments, at least some of the ceramic particles are formed of a ceramic material having a hardness of at least 1500 HV10 (Vickers hardness). In one or more embodiments, at least some of the ceramic particles are formed of a ceramic material having a hardness of at most 3200 HV10.

[0032] In one or more embodiments, at least some of the ceramic particles are formed of a ceramic material having a thermal conductivity of 90 W / mK or less, particularly 50 W / mK or less, and particularly 30 W / mK or less. In one or more embodiments, at least some of the ceramic particles are formed of a ceramic material having a thermal conductivity of at least 5 W / mK, particularly at least 10 W / mK.

[0033] In one or more embodiments, the ceramic particles include cubic carbides. In one or more embodiments, the cubic carbides include titanium carbide (TiC), tantalum carbide (TaC), niobium carbide (NbC), zirconium carbide (ZrC), hafnium carbide (HfC) and vanadium carbide (VC). Such cubic carbides have a face-centered cubic (fcc) or γ phase structure. In one or more embodiments, the sintered ceramic includes at least 1 weight %, at least 3 weight % or at least 10 weight % of cubic carbides. In one or more embodiments, the sintered ceramic includes up to 30 weight %, up to 35 weight % or up to 55 weight % of cubic carbides. In one or more embodiments, the cubic carbides include a maximum of 55 weight %, more particularly a maximum of 35 weight %, and most particularly a maximum of 20 weight % of TiC. In one or more embodiments, the cubic carbides include a maximum of 1 weight %, more particularly a maximum of 2 weight %, and most particularly at least 5 weight % of TiC. In one or more embodiments, the cubic carbide comprises TaC in an amount of up to 55 wt%, more particularly up to 35 wt%, and most particularly up to 20 wt%. In one or more embodiments, the cubic carbide comprises TaC in an amount of at least 0.5 wt%, more particularly at least 1 wt%, and most particularly at least 2 wt%. In one or more embodiments, the cubic carbide comprises NbC in an amount of up to 55 wt%, more particularly up to 35 wt%, and most particularly up to 20 wt%. In one or more embodiments, the cubic carbide comprises NbC in an amount of at least 1 wt%, more particularly at least 2 wt%, and most particularly at least 5 wt%.

[0034] In one or more embodiments, the ceramic particles include other hard particles other than tungsten carbide and cubic carbide. In one or more embodiments, the particle hardness of the other hard particles is at least 1000 HV10. In one or more embodiments, the hard particles are selected from nitrides or borides. In one or more embodiments, the nitrides include titanium nitride (TiN), binary and ternary nitrides, transition metal nitrides and high entropy nitrides.

[0035] Tungsten carbide and other ceramic particles are sintered together by a metal matrix material. In one or more embodiments, the metal matrix material includes at least one of cobalt, nickel or iron. In one or more embodiments, the sintered ceramic includes 3 wt % to 25 wt %, particularly 6 wt % to 15 wt % of the metal matrix material. For example, in one or more embodiments, the sintered ceramic includes 3 wt % to 25 wt %, particularly 6 wt % to 15 wt % of at least one of cobalt, nickel or iron.

[0036] In one or more embodiments, the thermal conductivity of the one or more metals used in the metal matrix material is at least 75 W / mK, particularly at least 85 W / mK, and most particularly at least 90 W / mK. For example, the thermal conductivity of cobalt is about 100 W / mK, the thermal conductivity of nickel is about 97.5 W / mK, and the thermal conductivity of iron is about 80 W / mK.

[0037] In one or more embodiments, the hardness of one or more metals used in the metal matrix material is at least 50 HV10, at least 100 HV10, or at least 125 HV10. For example, the hardness of cobalt is in the range of about 140 HV10 to 240 HV10, the hardness of nickel is about 65 HV10, and the hardness of iron is about 150 HV10. Due to the tungsten carbide and other hard ceramic particles, the hardness of the metal matrix material incorporated into the sintered ceramic will generally be harder than the individual metals constituting the metal matrix material. In particular, the hardness of the metal matrix material depends on the mean free path within the metal matrix material, which corresponds to the average width of the matrix material between the tungsten carbide and other hard ceramic particles. The smaller width of the metal matrix material between the tungsten carbide and other hard ceramic particles leads to a higher hardness. In addition, since some tungsten and carbon will be soluble in the metal matrix material, the metal matrix material will generally be harder than the individual metals constituting the metal matrix material.

[0038] In one or more embodiments, the grain size of the sintered ceramic formed by the tungsten carbide, ceramic particles and metal matrix material described above is 0.5 μm to 5 μm, in particular 1 μm to 1.3 μm. In one or more embodiments, the grain size is measured according to ISO 4499-2. In one or more embodiments, the hardness of the sintered ceramic at room temperature is at least 1000 HV10. In one or more embodiments, the hardness of the sintered ceramic at room temperature is at most 1800 HV10. In one or more embodiments, the hardness of the sintered ceramic at room temperature is in the range of 1300 HV10 to 1400 HV10.

[0039] Some conventional reciprocating saw blades may have teeth including sintered tungsten carbide tips. Such sintered tungsten carbide tips may also have a room temperature hardness of 1000 HV10 or higher. However, the room temperature hardness of any such sintered tungsten carbide cannot be maintained at temperatures associated with cutting, particularly when cutting hard materials such as cast iron. It is believed that the sintered tungsten carbide tip undergoes a significant reduction in hardness at operating temperatures, and therefore, such sintered tungsten carbide blades may not exhibit a longer wear life than the disclosed reciprocating saw blades with sintered ceramic tips. The wear resistance of a reciprocating saw blade can be quantified based on the speed or life (number of cuts) of a given material (e.g., cast iron pipe) under specific work instructions (e.g., cutting intervals, tool models used to perform cutting, etc.). According to wear resistance testing conducted by the inventors, the performance of a reciprocating saw blade having a tip 46 made of the disclosed sintered ceramic material is more than twice that of a reciprocating saw blade with a conventional tungsten carbide tip. The inventors speculate that the better performance is due to the incorporation of cubic carbide into the tip 46 of the reciprocating saw blade 10. Without wishing to be bound by theory, it is believed that such cubic carbide possesses a higher hardness than tungsten carbide at the temperatures generated at the teeth 34 during cutting. However, such cubic carbide is also believed to have a lower fracture toughness, and thus the reciprocating saw blade 10 according to the present disclosure is able to perform better in wear resistance tests by balancing higher high temperature hardness with lower fracture toughness.

[0040] Table 1 provides an example composition of a sintered ceramic that can be used as the tip 46 of the tooth 34 of the reciprocating saw blade 10 according to the present disclosure. As can be seen from Table 1, the largest component (61 weight percent) of the sintered carbide tip is tungsten carbide (WC), which has a thermal conductivity of about 120 W / mK and a room temperature hardness of about 2345 HV10. In addition, tungsten carbide has a hexagonal close-packed structure. The sintered ceramic also includes hard ceramic particles of titanium carbide (TiC), tantalum carbide (TaC), and niobium carbide (NbC). These carbides have a face-centered cubic (fcc) structure and have a thermal conductivity that is much lower than that of tungsten carbide. In particular, the thermal conductivity of these carbides is less than 30 W / mK. Cobalt (Co) and nickel (Ni) form a metal matrix material that sinters the tungsten carbide and ceramic particles together. These metals also have a thermal conductivity of about 100 W / mK.

[0041] Table 1 Example composition of sintered ceramics

[0042]

[0043] Therefore, the sintered ceramic material is mainly (75 wt%) made of a material with a relatively high thermal conductivity of about 100 W / mK or more. The added ceramic particles, especially fcc carbides (25 wt%), have a much lower thermal conductivity. This makes the process of joining the sintered ceramic tip 46 to the base 44 using a welding process difficult.

[0044] In particular, the reciprocating saw blade 10 has several small teeth 34 compared to other types of saw blades, such as circular saw blades. The small size of the tip 46 and base 44 of each tooth 34 and the thinness of the body 14 of the reciprocating saw blade can cause deformation and burn-through problems during joining, which are exacerbated by the low thermal conductivity and high melting temperature of cubic carbides in the sintered ceramic material. In conventional sintered tungsten carbide tips, the tungsten carbide melts or dissolves at the joint between the base (usually a steel alloy) and the tip, allowing the tungsten carbide and the steel of the base to mix. However, other ceramic particles, particularly fcc carbides, do not mix or do not significantly mix at the joint between the tip 46 and the base 44. In other cases, this problem can be solved by brazing the tip 46 to the base 44, which involves using a layer of molten brazing material to join the tip 46 to the base 44, but brazing is not a satisfactory solution for reciprocating saw blades, again because the large number of small teeth 34 makes brazing impractical and uneconomical.

[0045] Despite the problems associated with thermal joining, the inventors surprisingly and unexpectedly discovered that the sintered ceramic tip 46 can be welded to the corresponding base 44 of the tooth 34. That is, although the low thermal conductivity of ceramic particles, particularly fcc carbides (TiC, TaC, NbC), dictates that welding be used to join the tip 46 to the base 44 of the tooth 34, the inventors have discovered that welding can still provide an economical and effective way to join the sintered ceramic tip 46 to the body 14 of the reciprocating saw blade 10. In particular, and in contrast to a brazed joint or a mechanical joint, welding forms a metallurgical bond between the sintered ceramic tip 46 and the base 44 of the body 14. Furthermore, welding creates a diffusion zone in which the sintered ceramic, particularly the metal matrix, diffuses into the body 14 of the reciprocating saw blade and in which iron, such as the steel alloy of the body 14, diffuses into the sintered ceramic.

[0046] In one or more embodiments, the sintered ceramic is formed by sintering a powder of a metal matrix material, tungsten carbide, and ceramic particles into an insert for coupling with the base 44 of the tooth 34 of the reciprocating saw blade 10. In one or more embodiments, the inclusion of trace amounts (≤0.5 wt%) of additional cubic carbides (such as VC, NbC, or TaC) during sintering can inhibit the growth of tungsten carbide grains, thereby providing a fine or ultra-fine grain size. In one or more embodiments, the insert is coated with nickel to enhance wettability during welding and to form a diffusion barrier for carbides to enter the base 44 of the tooth 34. In one or more embodiments, the thickness of the nickel coating is 8 μm to 25 μm.

[0047] When preparing the reciprocating saw blade 10, an insert is provided for each base 44. Figure 4 As shown, the base 44 has a concave shape that matches the curvature of the cylindrical insert. However, in one or more other embodiments, the base 44 and the insert may have different complementary shapes, including other rounded or angled shapes. Figure 5 In one or more embodiments of the method 100 for forming the teeth 34 of the reciprocating saw blade 10 shown, a first step 101 involves securing a sintered ceramic insert against each base 44 of the reciprocating saw blade 10. Thereafter, in a second step 102, the insert is welded to the base 44 of the tooth 34 by heating until a molten joint is formed, by which the insert is joined to the base 44. After welding, the volume of the insert may be reduced due to the diffusion of the sintered ceramic into the material of the body 14. In one or more embodiments, the material of the body 14 may diffuse through up to half of the volume of the insert. In a third step 103, the insert and base 44 are ground to form the tip 46 and shape the teeth 34. Thereafter, the teeth 34 are arranged to form the desired sawing kerf. In addition, the reciprocating saw blade 10 may be heat treated to provide the desired properties of the body 14.

[0048] In one or more embodiments, the method 100 optionally involves a fourth step 104 in which the insert and the base 44 are edge pre-processed, which includes removing sharp edges, corners, and weld pools from the base 44. In particular, the edge pre-processing refines the micro-geometry of the cutting teeth 34 of the reciprocating saw blade 10. Due to the edge pre-processing, the amount of stress concentration and blunting on the cutting edge of each tooth 34 is reduced. Stress concentration is a peak that is inadvertently formed during the manufacturing process of the reciprocating saw blade 10. Stress concentration amplifies stress during processing, thereby shortening the life of the reciprocating saw blade 10. Similarly, the sharp cutting edge forms a lever that can convert force into tensile stress on the reciprocating saw blade 10 during cutting. These additional stresses may cause the sintered ceramic tip 46 to fracture, thereby compromising the integrity of the sintered ceramic tip 46 and / or exposing the sintered ceramic tip 46. In one or more other embodiments, the sintered ceramic tip 46 may not be edge pre-processed.

[0049] In one or more embodiments, the method 100 further comprises an optional fifth step 105 of coating the teeth 34 with a thin film ceramic coating. In one or more embodiments, the coating is selected from a nitride coating. In one or more embodiments, the nitride coating comprises one or more of aluminum, titanium, chromium or molybdenum. In one or more embodiments, the coating is selected from aluminum titanium nitride (AlTiN), aluminum chromium nitride (AlCrN), aluminum titanium chromium nitride (AlTiCrN) or titanium molybdenum nitride (TiMoN) and other possible materials. In one or more embodiments, the thin film ceramic coating is applied using chemical vapor deposition or physical vapor deposition (e.g., evaporation or sputtering) and other possible ways. Physical vapor deposition techniques are particularly preferred because physical vapor deposition techniques generally do not require high temperatures that may affect the desired properties of the reciprocating saw blade 10. In one or more embodiments, the coating is applied only to the sintered ceramic tip 46. In one or more other embodiments, the coating is applied to each tooth 34, including to the tip 46 and the base 44, but not to the body 14 of the reciprocating saw blade 10 that is outside the base 44. In still one or more other embodiments, the coating is applied to the entire cutting portion 32, but does not include application to the body 14 of the reciprocating saw blade 10. In still one or more other embodiments, the coating is applied to the entire reciprocating saw blade 10, including application to the body 14.

[0050] Figure 6An embodiment of a thin film ceramic coating 52 applied to the teeth 34, particularly to the sintered ceramic tip 46, is depicted. As mentioned, the coating 52 can be any of a variety of coatings, particularly nitride coatings applied via physical vapor deposition. The coating 52 can be selected to enhance performance in a particular environment. For example, a coating 52 of AlTiN increases hardness due to microstructural changes and solid solution hardening. In addition, the coating 52 of AlTiN will age harden at operating temperatures, thereby increasing the hardness during the life of the reciprocating saw blade 10. The coating of AlCrN provides high hardness and high wear resistance under extreme mechanical stresses, such as in high-speed applications. The coating of AlTiCrN provides high hardness, high toughness, and high oxidation temperature that can be used to cut stainless steel, high-temperature alloys, and other difficult-to-cut materials. As mentioned, other coatings 52, such as TiMoN, etc., may also be used.

[0051] In one or more embodiments, the coating 52 has a thickness 54 measured between an outer surface 56 of the sintered ceramic tip 46 (or cutting tooth 34) and an outer surface 58 of the coating 52. In one or more embodiments, the thickness 54 of the coating 52 is at least 2 μm. In one or more embodiments, the thickness 54 of the coating 52 is at least 3 μm. In one or more embodiments, the thickness 54 of the coating 52 is 2 μm to 5 μm. In one or more embodiments, the thickness 54 of the coating 52 is 3 μm to 4 μm. In one or more embodiments, the thickness 54 μm of the coating 52 is about 3.5 μm.

[0052] Figures 1 to 4 The illustrated embodiment of the reciprocating saw blade 10 is exemplary only and may be used in other types of reciprocating saw blades, such as Figure 7 The reciprocating saw blade 200 is shown with sintered ceramic tips disposed on the cutting teeth.

[0053] The reciprocating saw blade 200 includes a body 214 having a first end 216 spaced from a second end 218 along a longitudinal axis 220 of the reciprocating saw blade 200. An attachment portion 222 for coupling the reciprocating saw blade 200 to a reciprocating saw is connected to the body 214 at the first end 216. The body 214 includes a ridge edge 228 and a cutting edge 230 opposite the ridge edge 228. The cutting edge 230 includes a cutting portion 232 having a plurality of cutting teeth 234.

[0054] The cutting teeth 234 include a point 236, a rake face 238, and a relief face 240 and are separated by gullets 242. The gullets 242 of each cutting tooth 234 extend between the rake face 238 and the protrusion 262 of the adjacent tooth 234. The relief face 240 of each cutting tooth 234 terminates at the beginning of the protrusion 262. In one or more embodiments, each protrusion 262 is curved so that the protrusion 262 is generally circular. In one or more other embodiments, the protrusion 262 can have other shapes or forms. In one or more embodiments, the reciprocating saw blade 200 can be used to cut through a workpiece composed of wood having nails extending through or embedded therein, and the protrusion 262 helps prevent the nails from entering the gullets 242 of the cutting teeth 234 during the cutting operation.

[0055] In addition, in one or more embodiments, the reciprocating saw blade 200 includes a plunge point 264 for initiating plunge cutting. The plunge point 264 is formed on the second end 218 of the body 214 opposite the attachment portion 222. In one or more embodiments, the plunge point 264 includes a leading tooth 266 and a second tooth 268. The leading tooth 266 and the second tooth 268 are separated from the other cutting teeth 234 of the cutting portion 232 by a leading tooth groove 270, and the leading tooth groove 270 spans a distance greater than the distance spanned by the tooth grooves 242 between the cutting teeth 234.

[0056] The leading tooth 266 is shaped so that the leading tooth 266 can penetrate the workpiece without hooking or catching the material being cut, thereby allowing the entry point 264 to more easily penetrate the workpiece without chipping the workpiece. The second tooth 268 improves the plunge cutting performance by breaking up the chip material, thereby reducing the load on the leading tooth 266 and facilitating chip removal. This arrangement also improves cutting speed and saw blade life. In one or more embodiments, the entry point 264 includes a single second tooth 268 before the leading tooth groove 270. In one or more other embodiments, the entry point 264 includes a plurality of second teeth 268 positioned before the leading tooth groove 270. In one or more other embodiments, the second tooth 268 is omitted from the entry point 264.

[0057] The cutting teeth 234 , the leading teeth 266 , and the second teeth 268 of the reciprocating saw blade 200 may include tips of sintered ceramic material welded to the base of the teeth 234 as described above.

[0058] Other cutting tools having a plurality of small, relatively closely spaced teeth (e.g., having at least four teeth per inch) can also be prepared by welding a sintered ceramic material to the body of the cutting tool. Examples of other cutting tools include Figure 8 The swing saw blade 300 shown and Fig. 9The hole saw 400 shown. In one or more embodiments, the oscillating saw blade 300 and the hole saw 400 have respective teeth 334, 434 formed by tips of sintered ceramic material welded to the respective bodies 314, 414. As with the disclosed embodiments of the reciprocating saw blades 10, 200, it is expected that the service life and cutting performance of the oscillating saw blade 300 and the hole saw 400 will be improved by including the welded tips of the sintered ceramic material disclosed herein.

[0059] Unless otherwise expressly stated, it is not intended that any method described herein be construed as requiring that its steps be performed in a particular order. Therefore, in the event that a method claim does not actually recite the order in which its steps are to be followed or that the steps are not otherwise specifically stated in the claim or description to be limited to a particular order, it is not intended that any particular order be inferred. Furthermore, as used herein, the article "a" is intended to include one or more than one component or element and is not intended to be construed as meaning only one.

[0060] It will be apparent to those skilled in the art that various modifications and variations may be made without departing from the spirit or scope of the disclosed embodiments. Since modifications, combinations, sub-combinations and variations of the disclosed embodiments in combination with the spirit and substance of the various embodiments may occur to those skilled in the art, the disclosed embodiments should be interpreted as including all contents within the scope of the attached claims and their equivalents.

Claims

1. A reciprocating saw blade, comprising: a body including a first end, a second end spaced apart from the first end, a ridge edge extending between the first end and the second end, and a cutting edge extending between the first end and the second end, the cutting edge being opposite the ridge edge; a plurality of teeth defining a cutting portion of the cutting edge; Wherein, each of the plurality of teeth comprises: a base having an integral structure with the body, the base comprising a first material having a first hardness; a tip, the tip being welded to the base, the tip comprising a sintered ceramic material having a second hardness greater than the first hardness; wherein the sintered ceramic material comprises tungsten carbide particles and other ceramic particles held together by a metal matrix material; Wherein, the other ceramic particles include at least one ceramic material having a hardness of at least 1500 HV10 and a thermal conductivity of 50 W / mK or less.

2. The reciprocating saw blade according to claim 1, wherein: The at least one ceramic material includes a carbide having a face-centered cubic structure.

3. The reciprocating saw blade according to claim 2, wherein: The carbide includes at least one of titanium carbide (TiC), tantalum carbide (TaC), niobium carbide (NbC), zirconium carbide (ZrC), hafnium carbide (HfC), and vanadium carbide (VC).

4. The reciprocating saw blade according to claim 2 or claim 3, wherein: The carbide having the face-centered cubic structure accounts for 1 wt % to 55 wt % of the sintered ceramic material.

5. The reciprocating saw blade according to claim 4, wherein: The sintered ceramic material includes up to 55 wt. % of at least one of TiC, TaC or NbC.

6. The reciprocating saw blade according to claim 5, wherein: The sintered ceramic material includes about 12 wt % TiC, about 2 wt % TaC, and about 11 wt % NbC.

7. The reciprocating saw blade according to any one of claims 2 to 6, wherein: The sintered ceramic material includes at least 50% by weight of the tungsten carbide particles.

8. The reciprocating saw blade according to claim 7, wherein: The sintered ceramic material includes about 61% by weight of the tungsten carbide particles.

9. The reciprocating saw blade according to any one of claims 2 to 8, wherein: The sintered ceramic material includes 3 wt % to 25 wt % of the metal matrix material.

10. The reciprocating saw blade according to any one of claims 2 to 9, wherein: The metal matrix material includes at least one of cobalt, nickel or iron.

11. The reciprocating saw blade according to any one of claims 1 to 10, wherein: The sintered ceramic material has a hardness of at least 1000 HV10 at room temperature.

12. The reciprocating saw blade according to any one of claims 1 to 11, wherein: The other ceramic particles include particles made of nitride materials.

13. The reciprocating saw blade according to any one of claims 1 to 12, wherein: The plurality of teeth includes at least 4 teeth per inch along the cutting edge.

14. The reciprocating saw blade according to any one of claims 1 to 13, wherein: Each tooth of the plurality of teeth includes a rake face, a relief face, a point at an intersection between the rake face and the relief face, a tooth gap, and a projection, wherein adjacent teeth of the plurality of teeth are separated by the tooth gap and the projection.

15. The reciprocating saw blade according to any one of claims 1 to 14, wherein: The plurality of teeth further include a ceramic coating having a thickness of at most 10 μm.

16. The reciprocating saw blade of claim 15, wherein: The ceramic coating is applied via physical vapor deposition.

17. The reciprocating saw blade of any one of claims 1 to 16, further comprising an entry point disposed at the second end of the body, wherein: The entry point includes a leading tooth separated from the plurality of teeth by a leading tooth gullet that spans a greater distance than gullets between adjacent teeth in the plurality of teeth.

18. A reciprocating saw blade, comprising: a body including a first end, a second end spaced apart from the first end, a ridge edge extending between the first end and the second end, and a cutting edge extending between the first end and the second end, the cutting edge being opposite the ridge edge; a plurality of teeth defining a cutting portion of the cutting edge; Wherein, each of the plurality of teeth comprises: a base having an integral structure with the body, the base comprising a first material having a first hardness; a tip, the tip being welded to the base, the tip comprising a sintered ceramic material having a second hardness greater than the first hardness; wherein the sintered ceramic material comprises tungsten carbide particles and other particles containing one or more cubic carbides, the tungsten carbide particles and the other particles are held together by a metal matrix material; Wherein, the sintered ceramic material comprises at least 3 weight % of the other particles comprising the one or more cubic carbides.

19. The reciprocating saw blade of claim 18, wherein: The one or more cubic carbides include cubic carbides having a hardness of at least 1500 HV10 and a thermal conductivity of 50 W / mK or less.

20. The reciprocating saw blade of claim 18 or claim 19, wherein: The one or more cubic carbides include at least one of titanium carbide (TiC), tantalum carbide (TaC), niobium carbide (NbC), zirconium carbide (ZrC), hafnium carbide (HfC), and vanadium carbide (VC).

21. The reciprocating saw blade of any one of claims 18 to 20, wherein: The other particles comprising the one or more cubic carbides comprise at most 55 wt. % of the sintered ceramic material.

22. A reciprocating saw blade according to claim 20 or claim 21, wherein: The sintered ceramic material includes up to 55 wt. % of at least one of TiC, TaC or NbC.

23. The reciprocating saw blade of claim 22, wherein: The sintered ceramic material includes about 12 wt % TiC, about 2 wt % TaC, and about 11 wt % NbC.

24. The reciprocating saw blade of any one of claims 18 to 23, wherein: The sintered ceramic material includes at least 50% by weight of the tungsten carbide particles.

25. The reciprocating saw blade of claim 24, wherein: The sintered ceramic material includes about 61% by weight of the tungsten carbide particles.

26. The reciprocating saw blade of any one of claims 18 to 25, wherein: The sintered ceramic material includes 3 wt % to 25 wt % of the metal matrix material.

27. The reciprocating saw blade of any one of claims 18 to 26, wherein: The metal matrix material includes at least one of cobalt, nickel or iron.

28. The reciprocating saw blade of any one of claims 18 to 274, wherein: The sintered ceramic material has a hardness of at least 1000 HV10 at room temperature.

29. The reciprocating saw blade of any one of claims 18 to 28, wherein: The other ceramic particles also include particles made of nitride materials.

30. The reciprocating saw blade of any one of claims 18 to 29, wherein: The plurality of teeth includes at least 4 teeth per inch along the cutting edge.

31. The reciprocating saw blade of any one of claims 18 to 30, wherein: Each tooth of the plurality of teeth includes a rake face, a relief face, a point at an intersection between the rake face and the relief face, a tooth gap, and a projection, wherein adjacent teeth of the plurality of teeth are separated by the tooth gap and the projection.

32. The reciprocating saw blade of any one of claims 18 to 21, wherein: The plurality of teeth further include a ceramic coating having a thickness of at most 10 μm.

33. The reciprocating saw blade of claim 32, wherein: The ceramic coating is applied via physical vapor deposition.

34. The reciprocating saw blade of any one of claims 18 to 33, further comprising an entry point disposed at the second end of the body, wherein: The entry point includes a leading tooth separated from the plurality of teeth by a leading tooth gullet that spans a greater distance than gullets between adjacent teeth in the plurality of teeth.

35. A reciprocating saw blade, comprising: a body including a first end, a second end spaced apart from the first end, a ridge edge extending between the first end and the second end, and a cutting edge extending between the first end and the second end, the cutting edge being opposite the ridge edge; a plurality of teeth defining a cutting portion of the cutting edge; Wherein, each of the plurality of teeth comprises: a base having an integral structure with the body, the base comprising a first material having a first hardness; a tip, the tip being welded to the base, the tip comprising a sintered ceramic material having a second hardness greater than the first hardness; wherein the sintered ceramic material comprises tungsten carbide particles and other particles containing one or more ceramic materials, and the tungsten carbide particles and the other particles are held together by a metal matrix material; Wherein, the hardness of the sintered ceramic material at room temperature is at least 1000 HV10.

36. The reciprocating saw blade of claim 35, wherein: The one or more ceramic materials include at least one cubic carbide having a hardness of at least 1500 HV10 and a thermal conductivity of 50 W / mK or less.

37. A reciprocating saw blade according to claim 35 or claim 36, wherein: The one or more ceramic materials include at least one carbide having a face-centered cubic structure.

38. The reciprocating saw blade of claim 37, wherein: The at least one carbide having the face-centered cubic structure includes at least one of titanium carbide (TiC), tantalum carbide (TaC), niobium carbide (NbC), zirconium carbide (ZrC), hafnium carbide (HfC), and vanadium carbide (VC).

39. A reciprocating saw blade according to claim 37 or claim 38, wherein: The sintered ceramic material includes 1 wt % to 55 wt % of the at least one carbide having the face-centered cubic structure.

40. The reciprocating saw blade of any one of claims 37 to 39, wherein: The sintered ceramic material includes up to 55 wt. % of at least one of TiC, TaC or NbC.

41. The reciprocating saw blade of claim 40, wherein: The sintered ceramic material includes about 12 wt % TiC, about 2 wt % TaC, and about 11 wt % NbC.

42. The reciprocating saw blade of any one of claims 35 to 41, wherein: The sintered ceramic material includes at least 50% by weight of the tungsten carbide particles.

43. The reciprocating saw blade of claim 42, wherein: The sintered ceramic material includes about 61% by weight of the tungsten carbide particles.

44. A reciprocating saw blade as claimed in any one of claims 35 to 43, wherein: The sintered ceramic material includes 3 wt % to 25 wt % of the metal matrix material.

45. The reciprocating saw blade of any one of claims 35 to 43, wherein: The metal matrix material includes at least one of cobalt, nickel or iron.

46. ​​The reciprocating saw blade of any one of claims 35 to 45, wherein: The one or more ceramic materials include a nitride material.

47. The reciprocating saw blade of any one of claims 35 to 46, wherein: The plurality of teeth includes at least 4 teeth per inch along the cutting edge.

48. The reciprocating saw blade of any one of claims 35 to 47, wherein: Each tooth of the plurality of teeth includes a rake face, a relief face, a point at an intersection between the rake face and the relief face, a tooth gap, and a projection, wherein adjacent teeth of the plurality of teeth are separated by the tooth gap and the projection.

49. The reciprocating saw blade of any one of claims 35 to 48, wherein: The plurality of teeth further include a ceramic coating having a thickness of at most 10 μm.

50. The reciprocating saw blade of claim 49, wherein: The ceramic coating is applied via physical vapor deposition.

51. The reciprocating saw blade of any one of claims 35 to 50, further comprising an entry point disposed at the second end of the body, wherein: The entry point includes a leading tooth separated from the plurality of teeth by a leading tooth gullet that spans a greater distance than gullets between adjacent teeth in the plurality of teeth.

52. A cutting tool, comprising: a body, the body comprising a cutting edge; a plurality of teeth defining a cutting portion of the cutting edge, the plurality of teeth comprising at least four teeth per inch; Wherein, each of the plurality of teeth comprises: a base having an integral structure with the body, the base comprising a first material having a first hardness; a tip, the tip being welded to the base, the tip comprising a sintered ceramic material having a second hardness greater than the first hardness; wherein the sintered ceramic material comprises tungsten carbide particles and other particles containing one or more ceramic materials, and the tungsten carbide particles and the other particles are held together by a metal matrix material; Wherein, the hardness of the sintered ceramic material at room temperature is at least 1000 HV10.

53. The cutting tool of claim 52, wherein: The one or more ceramic materials include at least one cubic carbide having a hardness of at least 1500 HV10 and a thermal conductivity of 50 W / mK or less.

54. A cutting tool according to claim 52 or claim 53, wherein The one or more ceramic materials include at least one carbide having a face-centered cubic structure.

55. The cutting tool of claim 54, wherein: The at least one carbide having the face-centered cubic structure includes at least one of titanium carbide (TiC), tantalum carbide (TaC), niobium carbide (NbC), zirconium carbide (ZrC), hafnium carbide (HfC), and vanadium carbide (VC).

56. A cutting tool according to claim 54 or claim 55, wherein The sintered ceramic material includes 1 wt % to 55 wt % of the at least one carbide having the face-centered cubic structure.

57. A cutting tool according to any one of claims 54 to 56, wherein The sintered ceramic material includes up to 35 wt. % of at least one of TiC, TaC or NbC.

58. The cutting tool of claim 57, wherein: The sintered ceramic material includes about 12 wt % TiC, about 2 wt % TaC, and about 11 wt % NbC.

59. A cutting tool according to any one of claims 52 to 58, wherein The sintered ceramic material includes at least 50% by weight of the tungsten carbide particles.

60. The cutting tool of claim 58, wherein: The sintered ceramic material includes about 61% by weight of the tungsten carbide particles.

61. A cutting tool according to any one of claims 52 to 60, wherein The sintered ceramic material includes 3 wt % to 25 wt % of the metal matrix material.

62. A cutting tool according to any one of claims 52 to 61, wherein The metal matrix material includes at least one of cobalt, nickel or iron.

63. A cutting tool according to any one of claims 52 to 62, wherein: The one or more ceramic materials include a nitride material.

64. A cutting tool according to any one of claims 52 to 63, wherein The plurality of teeth further include a ceramic coating having a thickness of at most 10 μm.

65. The cutting tool of claim 64, wherein: The ceramic coating is applied via physical vapor deposition.

66. A cutting tool according to any one of claims 52 to 65, wherein The cutting tool is a reciprocating saw blade.

67. A cutting tool according to any one of claims 52 to 65, wherein The cutting tool is an oscillating saw blade.

68. A cutting tool according to any one of claims 52 to 65, wherein The cutting tool is a hole saw.

69. A method of attaching a tip comprising a sintered ceramic material to a body of a reciprocating saw blade to form a plurality of teeth, the method comprising: pressing the insert of sintered ceramic material against respective bases of the plurality of teeth, the bases being of unitary construction with the body of the reciprocating saw blade; welding the insert to the respective bases of the plurality of teeth; grinding the plurality of teeth to form the tip from the insert; wherein the sintered ceramic material comprises tungsten carbide particles and other particles containing one or more cubic carbides, the tungsten carbide particles and the other particles are held together by a metal matrix material; Wherein, the sintered ceramic material comprises at least 3 weight % of the one or more cubic carbides.

70. The method of claim 69, further comprising edge pre-processing to refine the micro-geometry of the plurality of teeth.

71. The method of claim 69 or claim 70, further comprising coating the plurality of teeth with a ceramic film having a thickness of at most 10 μm.

72. The method of claim 71, wherein: The ceramic film is applied via physical vapor deposition.

73. The method of any one of claims 69 to 72, wherein: The one or more cubic carbides include at least one cubic carbide having a hardness of at least 1500 HV10 and a thermal conductivity of 50 W / mK or less.

74. The method of any one of claims 69 to 73, wherein: The one or more cubic carbides include at least one of titanium carbide (TiC), tantalum carbide (TaC), niobium carbide (NbC), zirconium carbide (ZrC), hafnium carbide (HfC), and vanadium carbide (VC).

75. The method of any one of claims 69 to 74, wherein: The one or more cubic carbides comprise up to 55% by weight of the sintered ceramic material.

76. The method of claim 75, wherein: The sintered ceramic material includes up to 55 wt. % of at least one of TiC, TaC or NbC.

77. The method of claim 76, wherein: The sintered ceramic material includes about 12 wt % TiC, about 2 wt % TaC, and about 11 wt % NbC.

78. The method of any one of claims 69 to 77, wherein: The sintered ceramic material includes at least 50% by weight of the tungsten carbide particles.

79. The method of claim 78, wherein: The sintered ceramic material includes about 61% by weight of the tungsten carbide particles.

80. The method of any one of claims 69 to 79, wherein: The sintered ceramic material includes 3 wt % to 25 wt % of the metal matrix material.

81. The method of any one of claims 69 to 80, wherein: The metal matrix material includes at least one of cobalt, nickel or iron.

82. The method of any one of claims 69 to 81, wherein: The sintered ceramic material has a hardness of at least 1000 HV10 at room temperature.

83. The method of any one of claims 69 to 82, wherein: The other ceramic particles also include particles made of nitride materials.

84. The method of any one of claims 69 to 83, wherein: The plurality of teeth includes at least 4 teeth per inch along a cutting edge of the reciprocating saw blade.

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