Integral compression molding method for hard alloy liner of high-capacity ball mill with reinforcing ribs

Abstract

The liner comprises a shell and a bottom plate, the shell is composed of a small cylindrical surface, a small conical surface, a large conical surface and a large cylindrical surface which are sequentially connected from top to bottom, the bottom plate is arranged at the bottom of the large cylindrical surface, and the method comprises the following steps that a mold is assembled; and pressing, demolding and sintering are conducted, the pressed inner container shell and the pre-sintered bottom plate are subjected to barge burning, and finally the hard alloy inner container of the large-capacity ball mill is obtained. Through the mode that the square core shaft is combined with the four-section inner mold, the mold can be conveniently installed and demolded.

Description

Technical Field

[0001] The invention relates to the technical field of hard alloy manufacturing, in particular to an integral pressing method for a hard alloy inner liner of a large-capacity ball mill with reinforcing ribs. Background Art

[0002] In the production of cemented carbide products, wet grinding is a very important process, and its efficiency directly affects the quality of cemented carbide products. The wet mill is composed of a cylinder (liner), a reduction motor, a sprocket chain, a bearing, a cylinder, a frame and a control system. Among them, the cylinder (liner) is one of the most important components. In the 1980s and 1990s, the ball mill initially used alloy liners, which were inlaid with hundreds of alloy liners to form the liner. During the production process, the alloy liners were easy to fall off, and maintenance was often required in the middle, which seriously affected the product delivery time. In this case, the non-magnetic stainless steel liner ball mill was produced. The 200L / 300L liner of the ball mill (also called wet mill) made of non-magnetic stainless steel material has the advantages of easy production and relatively low cost. The disadvantage is that it is easy to wear, and the abrasive material is mixed with the ball mill material, which increases the impurities in the ball mill material and affects the performance of the ball mill material. In order to reduce the doping of ball mill materials, some existing technologies have also designed linings made of cemented carbide to replace stainless steel, such as a new cemented carbide stirring ball mill disclosed in Chinese patent CN106513691A. However, due to the limitations of the cemented carbide liner or inner tank, it is difficult to make a large-capacity cemented carbide inner tank of more than 200L through one-piece molding.

[0003] The information disclosed in the above background technology section is only intended to increase the understanding of the overall background of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0004] In view of the above existing defects, the present invention aims to provide a method for integrally pressing a large-capacity ball mill carbide liner with reinforcing ribs. Through special mold design, a square mandrel combined with a four-petal inner mold can facilitate the installation and demoulding of the mold.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for integrally pressing a large-capacity ball mill hard alloy liner with a reinforcing rib installation groove, characterized in that the liner comprises a shell and a bottom plate, the shell is a small cylindrical surface, a small conical surface, a large conical surface, and a large cylindrical surface connected in sequence from top to bottom, a bottom plate is arranged at the bottom of the large cylindrical surface, and more than two reinforcing ribs are longitudinally and parallelly arranged on the inner side of the large cylinder from top to bottom, and the method comprises the following steps:

[0007] Step 1: Assemble the mold. The mold is an assembled mold, including a square mandrel and a four-petal inner mold fitted with the four sides of the square mandrel. After the four-petal inner mold is assembled to the four sides of the square mandrel, the shape of its outer side surface is adapted to the shell, and a groove structure adapted to the reinforcing rib is longitudinally parallelly arranged from top to bottom at the corresponding position of the lower end of the four-petal inner mold; first fix one end of the square mandrel on the first plug, then install the four-petal inner mold on the four sides of the square mandrel, put an elastic mold sleeve on the outer side of the four-petal inner mold, put cemented carbide powder between the elastic mold sleeve and the four-petal inner mold, and finally fix the other end of the square mandrel with the second plug to complete the assembly of the pressing mold;

[0008] Step 2: Pressing: Place the mold filled with cemented carbide powder into a dry bag cold isostatic press for pressing. When pressurizing, the circumference of the elastic mold sleeve is evenly compressed, and the two ends of the elastic mold sleeve are not compressed;

[0009] Step 3: demoulding: first remove the first plug and the second plug, then remove the square mandrel and the four-petal inner mold, and then remove the pressed inner shell from the elastic mold sleeve;

[0010] Step 4: Sintering: Sinter the pressed inner shell and the pre-sintered bottom plate to obtain a large-capacity ball mill carbide inner shell with reinforced ribs.

[0011] Furthermore, the bottom plate is a disc-shaped structure, and the diameter of the bottom plate after pre-sintering is 0.85-0.95 times the diameter of the inner cross-section of the large cylindrical surface.

[0012] Furthermore, the cemented carbide powder is a cemented carbide of grade YG10-YG25.

[0013] Furthermore, the content of cobalt and / or nickel in the cemented carbide powder is greater than 10%.

[0014] Furthermore, the pre-sintering is to place the pressed bottom plate into a sintering furnace, heat it to 1350° C.-1380° C., keep it warm for 30-50 minutes, and cool it down and take it out.

[0015] Furthermore, the sintering process comprises the following steps: (1) first filling the furnace with vacuum; (2) raising the temperature by 100°C every 10 minutes to 1300-1350°C for vacuum sintering; keeping the temperature for 1.5-2.5 hours; (3) filling with argon gas at the end of vacuum sintering, carrying out argon protection sintering at a temperature of 1350-1450°C, and keeping the temperature for 1.5-2 hours; (4) after the argon protection sintering is completed, cooling naturally.

[0016] Furthermore, the capacity of the inner tank is 200 to 300L.

[0017] Furthermore, the inner diameter of the cross section of the large cylindrical surface is 620-707 mm.

[0018] Furthermore, the wall thickness of the inner liner is 14 to 15 mm.

[0019] Furthermore, the weight of the inner liner is 429-655 kg.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention applies a mold designed for a large-capacity ball mill cemented carbide liner with a special shape. The square mandrel is combined with a four-petal inner mold to facilitate the installation and demolding of the mold. The liner shell is formed by a pre-sintered bottom plate combined with cold isostatic pressing. The shell and the bottom plate are sintered together after assembly, and finally the shell and the bottom plate are completely fitted together to achieve one-piece forming. Experiments have found that the large-capacity ball mill cemented carbide liner made by this method has a longer service life and higher rigidity than the same type of stainless steel liner. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The following is a schematic diagram of the structure of the integral cemented carbide liner according to an embodiment of the present invention;

[0023] Figure 2 The following is a schematic diagram of the structure of the cemented carbide integral liner assembly mold according to an embodiment of the present invention;

[0024] Figure 3 : A top view of the cemented carbide integral liner assembly mold according to an embodiment of the present invention;

[0025] Figure 4 : An exploded view of a cemented carbide integral liner assembly mold according to an embodiment of the present invention;

[0026] Figure 5 : A schematic diagram of cold isostatic pressing of a cemented carbide integral liner according to an embodiment of the present invention;

[0027] Figure 6 : A schematic diagram of the assembly of the integral cemented carbide inner chamber and the bottom plate according to an embodiment of the present invention.

[0028] In the figure, 1-small cylindrical surface; 2-small conical surface; 3-large conical surface; 4-large cylindrical surface; 5-bottom plate; 6-first petal inner mold; 7-second petal inner mold; 8-third petal inner mold; 9-fourth petal inner mold; 10-square mandrel; 11-first plug; 12-second plug; 14-hard alloy powder; 13-assembled mold; 15-elastic mold sleeve; 16-pre-fired bottom plate; 17-groove; 18-reinforcement rib. DETAILED DESCRIPTION

[0029] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in combination with the embodiments and accompanying drawings. In the description of this embodiment, it should be understood that the terms indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, which are only for the convenience of describing this embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0030] Embodiment 1, a 300L ribbed cemented carbide integral liner, the indicators are: height 1100mm, diameter 707mm, wall thickness 14mm, weight 535kg; the cemented carbide is YG10 grade cemented carbide, the liner includes a shell and a bottom plate 5, the shell is a small cylindrical surface 1, a small conical surface 2, a large conical surface 3, a large cylindrical surface 4 connected in sequence from top to bottom, the bottom plate 5 is arranged at the bottom of the large cylindrical surface 4, and 4 reinforcing ribs 18 are arranged longitudinally and parallelly from top to bottom on the inner side of the large cylinder, the width of the reinforcing rib 18 is 20mm, the height is 15mm, and the length is slightly less than the height of the large cylindrical surface 4, which is 600mm. The method comprises the following steps:

[0031] Step 1: Assemble the mold. The mold is an assembled mold 13, including a square mandrel 10 and a four-petal inner mold fitted with the four sides of the square mandrel 10. The four-petal inner molds are respectively a first petal inner mold 6, a second petal inner mold 7, and a third petal inner mold 8; a fourth petal inner mold 9. After the four-petal inner molds are assembled to the four sides of the square mandrel 10, the shape of the outer side surface thereof is adapted to the shell, and a groove 17 structure adapted to the reinforcing rib 18 is longitudinally and parallelly arranged from top to bottom at the corresponding position of the lower end of the four-petal inner mold; first fix one end of the square mandrel 10 on the first plug 11, and then install the four-petal inner mold on the four sides of the square mandrel 10, put an elastic mold sleeve on the outer side of the four-petal inner mold, put a cemented carbide powder 14 between the elastic mold sleeve and the four-petal inner mold, and finally fix the other end of the square mandrel 10 with the second plug 12, thus completing the assembly of the pressing mold;

[0032] Step 2: Pressing: Put the mold filled with cemented carbide powder 14 into a dry bag cold isostatic press for pressing. When pressurizing, the circumference of the elastic mold sleeve is evenly compressed, and the two ends of the elastic mold sleeve are not compressed.

[0033] Step 3: demoulding, first take out the first plug 11 and the second plug 12, then take out the square mandrel 10 and the four-petal inner mold, and then take out the pressed inner shell from the elastic mold sleeve;

[0034] Step 4, sintering: the pressed inner shell and the pre-sintered bottom plate 5 are sintered to finally obtain a large-capacity ball mill carbide inner shell with reinforced ribs.

[0035] In this embodiment, the bottom plate 5 is a disc-shaped structure. The diameter of the pre-sintered bottom plate 16 after pre-sintering is 0.85 times the diameter of the inner cross-section of the large cylindrical surface 4, that is, 601 mm, and the thickness is 15 mm.

[0036] In this embodiment, the cobalt content of the cemented carbide is greater than 10%.

[0037] In this embodiment, the pre-sintering is to put the pressed bottom plate 5 into a sintering furnace, heat it to 1350°C at a rate of 100°C every 10 minutes, keep it warm for 50 minutes, cool it naturally, and then take it out. After taking it out, the two planes need to be polished, and the inner hole needs to be polished with the plane as the reference to ensure that the inner hole is perpendicular to the two end surfaces.

[0038] In this embodiment, the sintering process includes the following steps: (1) first fill the furnace with vacuum; (2) increase the temperature by 100°C every 10 minutes to 1300°C for vacuum sintering; keep the temperature for 2.5 hours; (3) fill with argon gas at the end of vacuum sintering, perform argon protection sintering at 1350°C, and keep the temperature for 2 hours; (4) after the argon protection sintering is completed, cool naturally.

[0039] Embodiment 2, a 300L ribbed cemented carbide integral liner, the indicators are: height 1100mm, diameter 707mm, wall thickness 14mm, weight 595kg; the cemented carbide is a YG10-YG25 grade cemented carbide, the liner comprises a shell and a bottom plate 5, the shell is a small cylindrical surface 1, a small conical surface 2, a large conical surface 3, a large cylindrical surface 4 connected in sequence from top to bottom, a bottom plate 5 is arranged at the bottom of the large cylindrical surface 4, 8 ribs 18 are arranged longitudinally and parallelly from top to bottom on the inner side of the large cylinder, the width of the rib 18 is 20mm, the height is 15mm, and the length is slightly less than the height of the large cylindrical surface 4, which is 600mm, the method comprises the following steps:

[0040] Step 1: Assemble the mold. The mold is an assembled mold 13, including a square mandrel 10 and a four-petal inner mold fitted with the four sides of the square mandrel 10. The four-petal inner molds are respectively a first petal inner mold 6, a second petal inner mold 7, and a third petal inner mold 8; a fourth petal inner mold 9. After the four-petal inner molds are assembled to the four sides of the square mandrel 10, the shape of the outer side surface thereof is adapted to the shell, and a groove 17 structure adapted to the reinforcing rib 18 is longitudinally and parallelly arranged from top to bottom at the corresponding position of the lower end of the four-petal inner mold; first fix one end of the square mandrel 10 on the first plug 11, and then install the four-petal inner mold on the four sides of the square mandrel 10, put an elastic mold sleeve on the outer side of the four-petal inner mold, put a cemented carbide powder 14 between the elastic mold sleeve and the four-petal inner mold, and finally fix the other end of the square mandrel 10 with the second plug 12, thus completing the assembly of the pressing mold;

[0041] Step 2: Pressing: Put the mold filled with cemented carbide powder 14 into a dry bag cold isostatic press for pressing. When pressurizing, the circumference of the elastic mold sleeve is evenly compressed, and the two ends of the elastic mold sleeve are not compressed.

[0042] Step 3: demoulding, first take out the first plug 11 and the second plug 12, then take out the square mandrel 10 and the four-petal inner mold, and then take out the pressed inner shell from the elastic mold sleeve;

[0043] Step 4, sintering: the pressed inner shell and the pre-sintered bottom plate 5 are sintered to finally obtain a large-capacity ball mill carbide inner shell with reinforced ribs.

[0044] In this embodiment, the bottom plate 5 is a disc-shaped structure. After pre-sintering, the diameter of the pre-sintered bottom plate 16 is 0.90 times the diameter of the inner cross-section of the large cylindrical surface 4, that is, 636 mm, and the thickness is 15 mm.

[0045] In this embodiment, the cobalt content in the cemented carbide accounts for more than 10%.

[0046] In this embodiment, the pre-sintering is to put the pressed bottom plate 5 into a sintering furnace, heat it to 1380°C at a rate of 100°C every 10 minutes, keep it warm for 30 minutes, cool it naturally, and then take it out. After taking it out, it is necessary to polish the two planes, polish the inner hole with the plane as the reference, and ensure that the inner hole is perpendicular to the two end surfaces.

[0047] In this embodiment, the sintering process includes the following steps: (1) first fill the furnace with vacuum; (2) increase the temperature by 100°C every 10 minutes to 1350°C for vacuum sintering; keep it warm for 2 hours; (3) fill argon gas at the end of vacuum sintering, perform argon protection sintering at 1450°C, and keep it warm for 1.5 hours; (4) after the argon protection sintering is completed, cool it naturally.

[0048] Embodiment 3, a 300L ribbed cemented carbide integral liner, with the following indicators: height 1100mm, diameter 707mm, wall thickness 14mm, weight 655kg; the cemented carbide is a YG10-YG25 grade cemented carbide, the liner comprises a shell and a bottom plate 5, the shell is a small cylindrical surface 1, a small conical surface 2, a large conical surface 3, a large cylindrical surface 4 connected in sequence from top to bottom, a bottom plate 5 is arranged at the bottom of the large cylindrical surface 4, 12 ribs 18 are arranged longitudinally and parallelly from top to bottom on the inner side of the large cylinder, the ribs 18 have a width of 20mm, a height of 15mm, and a length slightly smaller than the height of the large cylindrical surface 4, which is 600mm, the method comprises the following steps:

[0049] Step 1: Assemble the mold. The mold is an assembled mold 13, including a square mandrel 10 and a four-petal inner mold fitted with the four sides of the square mandrel 10. The four-petal inner molds are respectively a first petal inner mold 6, a second petal inner mold 7, and a third petal inner mold 8; a fourth petal inner mold 9. After the four-petal inner molds are assembled to the four sides of the square mandrel 10, the shape of the outer side surface thereof is adapted to the shell, and a groove 17 structure adapted to the reinforcing rib 18 is longitudinally and parallelly arranged from top to bottom at the corresponding position of the lower end of the four-petal inner mold; first fix one end of the square mandrel 10 on the first plug 11, and then install the four-petal inner mold on the four sides of the square mandrel 10, put an elastic mold sleeve on the outer side of the four-petal inner mold, put a cemented carbide powder 14 between the elastic mold sleeve and the four-petal inner mold, and finally fix the other end of the square mandrel 10 with the second plug 12, thus completing the assembly of the pressing mold;

[0050] Step 2: Pressing: Put the mold filled with cemented carbide powder 14 into a dry bag cold isostatic press for pressing. When pressurizing, the circumference of the elastic mold sleeve is evenly compressed, and the two ends of the elastic mold sleeve are not compressed.

[0051] Step 3: demoulding, first take out the first plug 11 and the second plug 12, then take out the square mandrel 10 and the four-petal inner mold, and then take out the pressed inner shell from the elastic mold sleeve;

[0052] Step 4, sintering: the pressed inner shell and the pre-sintered bottom plate 5 are sintered to finally obtain a large-capacity ball mill carbide inner shell with reinforced ribs.

[0053] In this embodiment, the bottom plate 5 is a disc-shaped structure. After pre-sintering, the diameter of the pre-sintered bottom plate 16 is 0.95 times the diameter of the inner cross-section of the large cylindrical surface 4, that is, 671 mm, and the thickness is 15 mm.

[0054] In this embodiment, the cobalt content in the cemented carbide accounts for more than 10%.

[0055] In this embodiment, the pre-sintering is to put the pressed bottom plate 5 into a sintering furnace, heat it to 1385°C at a rate of 100°C every 10 minutes, keep it warm for 45 minutes, cool it naturally, and then take it out. After taking it out, the two planes need to be polished, and the inner hole needs to be polished with the plane as the reference to ensure that the inner hole is perpendicular to the two end surfaces.

[0056] In this embodiment, the sintering process includes the following steps: (1) first fill the furnace with vacuum; (2) increase the temperature by 100°C every 10 minutes to 1340°C for vacuum sintering; keep the temperature for 2.2 hours; (3) fill argon gas at the end of vacuum sintering, perform argon protection sintering at 1400°C, and keep the temperature for 1.8 hours; (4) after the argon protection sintering is completed, cool naturally.

[0057] Example 4, a 200L ribbed cemented carbide integral liner, with the following indicators: height 1030mm, diameter 620mm, wall thickness 14mm, weight 429kg; the cemented carbide is YG10 grade cemented carbide, the liner includes a shell and a bottom plate 5, the shell is a small cylindrical surface 1, a small conical surface 2, a large conical surface 3, and a large cylindrical surface 4 connected in sequence from top to bottom, the bottom plate 5 is arranged at the bottom of the large cylindrical surface 4, and 4 reinforcing ribs 18 are arranged longitudinally and parallelly from top to bottom on the inner side of the large cylinder, the width of the reinforcing rib 18 is 20mm, the height is 15mm, and the length is slightly less than the height of the large cylindrical surface 4, which is 600mm, and the method comprises the following steps:

[0058] Step 1: Assemble the mold. The mold is an assembled mold 13, including a square mandrel 10 and a four-petal inner mold fitted with the four sides of the square mandrel 10. The four-petal inner molds are respectively a first petal inner mold 6, a second petal inner mold 7, and a third petal inner mold 8; a fourth petal inner mold 9. After the four-petal inner molds are assembled to the four sides of the square mandrel 10, the shape of the outer side surface thereof is adapted to the shell, and a groove 17 structure adapted to the reinforcing rib 18 is longitudinally and parallelly arranged from top to bottom at the corresponding position of the lower end of the four-petal inner mold; first fix one end of the square mandrel 10 on the first plug 11, and then install the four-petal inner mold on the four sides of the square mandrel 10, put an elastic mold sleeve on the outer side of the four-petal inner mold, put a cemented carbide powder 14 between the elastic mold sleeve and the four-petal inner mold, and finally fix the other end of the square mandrel 10 with the second plug 12, thus completing the assembly of the pressing mold;

[0059] Step 2: Pressing: Put the mold filled with cemented carbide powder 14 into a dry bag cold isostatic press for pressing. When pressurizing, the circumference of the elastic mold sleeve is evenly compressed, and the two ends of the elastic mold sleeve are not compressed.

[0060] Step 3: demoulding, first take out the first plug 11 and the second plug 12, then take out the square mandrel 10 and the four-petal inner mold, and then take out the pressed inner shell from the elastic mold sleeve;

[0061] Step 4, sintering: sinter the pressed inner shell and the pre-sintered bottom plate 5, and finally obtain a large-capacity ball mill carbide inner shell with reinforced ribs.

[0062] In this embodiment, the bottom plate 5 is a disc-shaped structure. After pre-sintering, the diameter of the pre-sintered bottom plate 16 is 0.85 times the diameter of the inner cross-section of the large cylindrical surface 4, that is, 527 mm, and the thickness is 15 mm.

[0063] In this embodiment, the pre-sintering is to put the pressed bottom plate 5 into a sintering furnace, heat it to 1350°C at a rate of 100°C every 10 minutes, keep it warm for 25 minutes, cool it naturally, and then take it out. After taking it out, the two planes need to be polished, and the inner hole needs to be polished with the plane as the reference to ensure that the inner hole is perpendicular to the two end surfaces.

[0064] In this embodiment, the sintering process includes the following steps: (1) first fill the furnace with vacuum; (2) increase the temperature by 100°C every 10 minutes to 1300°C for vacuum sintering; keep the temperature for 2.0 hours; (3) fill argon gas at the end of vacuum sintering, perform argon protection sintering at 1350°C, and keep the temperature for 1.5 hours; (4) after the argon protection sintering is completed, cool naturally.

[0065] Example 5, a 200L ribbed cemented carbide integral liner, with the following indicators: height 1030mm, diameter 620mm, wall thickness 14mm, weight 469kg; the cemented carbide is YG15 grade cemented carbide, the liner comprises a shell and a bottom plate 5, the shell is a small cylindrical surface 1, a small conical surface 2, a large conical surface 3, a large cylindrical surface 4 connected in sequence from top to bottom, the bottom plate 5 is arranged at the bottom of the large cylindrical surface 4, 8 ribs 18 are arranged longitudinally and parallelly from top to bottom on the inner side of the large cylinder, the ribs 18 have a width of 20mm, a height of 15mm, and a length slightly less than the height of the large cylindrical surface 4, the method comprises the following steps:

[0066] Step 1: Assemble the mold. The mold is an assembled mold 13, including a square mandrel 10 and a four-petal inner mold fitted with the four sides of the square mandrel 10. The four-petal inner molds are respectively a first petal inner mold 6, a second petal inner mold 7, and a third petal inner mold 8; a fourth petal inner mold 9. After the four-petal inner molds are assembled to the four sides of the square mandrel 10, the shape of the outer side surface thereof is adapted to the shell, and a groove 17 structure adapted to the reinforcing rib 18 is longitudinally and parallelly arranged from top to bottom at the corresponding position of the lower end of the four-petal inner mold; first fix one end of the square mandrel 10 on the first plug 11, and then install the four-petal inner mold on the four sides of the square mandrel 10, put an elastic mold sleeve on the outer side of the four-petal inner mold, put a cemented carbide powder 14 between the elastic mold sleeve and the four-petal inner mold, and finally fix the other end of the square mandrel 10 with the second plug 12, thus completing the assembly of the pressing mold;

[0067] Step 2: Pressing: Put the mold filled with cemented carbide powder 14 into a dry bag cold isostatic press for pressing. When pressurizing, the circumference of the elastic mold sleeve is evenly compressed, and the two ends of the elastic mold sleeve are not compressed.

[0068] Step 3: demoulding, first take out the first plug 11 and the second plug 12, then take out the square mandrel 10 and the four-petal inner mold, and then take out the pressed inner shell from the elastic mold sleeve;

[0069] Step 4, sintering: the pressed inner shell and the pre-sintered bottom plate 5 are sintered to finally obtain a large-capacity ball mill carbide inner shell with reinforced ribs.

[0070] In this embodiment, the pre-sintering is to put the pressed bottom plate 5 into a sintering furnace, heat it to 1380°C at a rate of 100°C every 10 minutes, keep it warm for 25 minutes, cool it naturally, and then take it out. After taking it out, the two planes need to be polished, and the inner hole needs to be polished with the plane as the reference to ensure that the inner hole is perpendicular to the two end surfaces.

[0071] In this embodiment, the sintering process includes the following steps: (1) first fill the furnace with vacuum; (2) increase the temperature by 100°C every 10 minutes to 1350°C for vacuum sintering; keep it warm for 1.7 hours; (3) fill argon gas at the end of vacuum sintering, perform argon protection sintering at 1450°C, and keep it warm for 1.3 hours; (4) after the argon protection sintering is completed, cool it naturally.

[0072] Example 6, a 200L ribbed cemented carbide integral liner, with the following indicators: height 1030mm, diameter 620mm, wall thickness 14mm, weight 509kg; the cemented carbide is YG25 grade cemented carbide, the liner comprises a shell and a bottom plate 5, the shell is a small cylindrical surface 1, a small conical surface 2, a large conical surface 3, a large cylindrical surface 4 connected in sequence from top to bottom, a bottom plate 5 is arranged at the bottom of the large cylindrical surface 4, 12 reinforcement ribs 18 are arranged longitudinally and parallelly from top to bottom on the inner side of the large cylinder, the width of the reinforcement rib 18 is 20mm, the height is 15mm, and the length is slightly less than the height of the large cylindrical surface 4, the method comprises the following steps:

[0073] Step 1: Assemble the mold. The mold is an assembled mold 13, including a square mandrel 10 and a four-petal inner mold fitted with the four sides of the square mandrel 10. The four-petal inner molds are respectively a first petal inner mold 6, a second petal inner mold 7, and a third petal inner mold 8; a fourth petal inner mold 9. After the four-petal inner molds are assembled to the four sides of the square mandrel 10, the shape of the outer side surface thereof is adapted to the shell, and a groove 17 structure adapted to the reinforcing rib 18 is longitudinally and parallelly arranged from top to bottom at the corresponding position of the lower end of the four-petal inner mold; first fix one end of the square mandrel 10 on the first plug 11, and then install the four-petal inner mold on the four sides of the square mandrel 10, put an elastic mold sleeve on the outer side of the four-petal inner mold, put a cemented carbide powder 14 between the elastic mold sleeve and the four-petal inner mold, and finally fix the other end of the square mandrel 10 with the second plug 12, thus completing the assembly of the pressing mold;

[0074] Step 2: Pressing: Put the mold filled with cemented carbide powder 14 into a dry bag cold isostatic press for pressing. When pressurizing, the circumference of the elastic mold sleeve is evenly compressed, and the two ends of the elastic mold sleeve are not compressed.

[0075] Step 3: demoulding, first take out the first plug 11 and the second plug 12, then take out the square mandrel 10 and the four-petal inner mold, and then take out the pressed inner shell from the elastic mold sleeve;

[0076] Step 4, sintering: sinter the pressed inner shell and the pre-sintered bottom plate 5, and finally obtain a large-capacity ball mill carbide inner shell with reinforced ribs.

[0077] In this embodiment, the bottom plate 5 is a disc-shaped structure. After pre-sintering, the diameter of the bottom plate 5 is 0.95 times the diameter of the inner cross-section of the large cylindrical surface 4, that is, 589 mm, and the thickness is 15 mm.

[0078] In this embodiment, the pre-sintering is to put the pressed bottom plate 5 into a sintering furnace, heat it to 1360°C at a rate of 100°C every 10 minutes, keep it warm for 35 minutes, cool it naturally, and then take it out. After taking it out, it is necessary to polish the two planes, polish the inner hole with the plane as the reference, and ensure that the inner hole is perpendicular to the two end surfaces.

[0079] In this embodiment, the sintering process includes the following steps: (1) first fill the furnace with vacuum; (2) increase the temperature by 100°C every 10 minutes to 1320°C for vacuum sintering; keep the temperature for 1.5 hours; (3) fill argon gas at the end of vacuum sintering, perform argon protection sintering at 1400°C, and keep the temperature for 1.5 hours; (4) after the argon protection sintering is completed, cool naturally.

[0080] Comparative Example 1

[0081] 200L cemented carbide overall indicators: height 1030mm, diameter 620mm, weight 389kg; cemented carbide is YG16 grade cemented carbide, a large-capacity ball mill cemented carbide liner integral pressing molding method, the liner includes a shell and a bottom plate 5, the shell is a small cylindrical surface 1, a small conical surface 2, a large conical surface 3, a large cylindrical surface 4 connected in sequence from top to bottom, and a bottom plate 5 is arranged at the bottom of the large cylindrical surface 4, the method includes the following steps:

[0082] Step 1: Assemble the mold. The mold is an assembled mold 13, including a square mandrel 10 and a four-petal inner mold fitted with four sides of the square mandrel 10. The four-petal inner molds are respectively a first petal inner mold 6, a second petal inner mold 7, and a third petal inner mold 8; a fourth petal inner mold 9. After the four-petal inner molds are assembled to the four sides of the square mandrel 10, the shape of the outer side surface thereof is adapted to the shell; first fix one end of the square mandrel 10 on the first plug 11, and then install the four-petal inner mold on the four sides of the square mandrel 10, put an elastic mold sleeve on the outer side of the four-petal inner mold, put a cemented carbide powder 14 between the elastic mold sleeve and the four-petal inner mold, and finally fix the other end of the square mandrel 10 with the second plug 12, thus completing the assembly of the pressing mold;

[0083] Step 2: Pressing: Put the mold filled with cemented carbide powder 14 into a dry bag cold isostatic press for pressing. When pressurizing, the circumference of the elastic mold sleeve is evenly compressed, and the two ends of the elastic mold sleeve are not compressed.

[0084] Step 3: demoulding, first take out the first plug 11 and the second plug 12, then take out the square mandrel 10 and the four-petal inner mold, and then take out the pressed inner shell from the elastic mold sleeve;

[0085] Step 4: Sintering: Sinter the pressed inner shell and the pre-sintered bottom plate 5 to obtain a large-capacity ball mill carbide inner shell.

[0086] In this comparative example, the bottom plate 5 is a disc-shaped structure. After pre-sintering, the diameter of the bottom plate 5 is 0.90 times the diameter of the inner cross-section of the large cylindrical surface 4, that is, 558 mm, and the thickness is 15 mm.

[0087] In this comparative example, the pre-sintering is to put the pressed bottom plate 5 into a sintering furnace, heat it to 1370°C at a rate of 100°C every 10 minutes, keep it warm for 30 minutes, cool it naturally, and then take it out. After taking it out, it is necessary to polish the two planes, polish the inner hole with the plane as the reference, and ensure that the inner hole is perpendicular to the two end surfaces.

[0088] In this comparative example, the sintering process includes the following steps: (1) first filling the furnace with a vacuum; (2) raising the temperature by 100°C every 10 minutes to 1350°C for vacuum sintering; and keeping the temperature for 1.5 hours; (3) filling with argon gas at the end of the vacuum sintering, and carrying out argon-protected sintering at a temperature of 1350°C for 1 hour; (4) after the argon-protected sintering is completed, cooling naturally.

[0089] Comparative Example 2

[0090] A 300L cemented carbide integral liner has the following specifications: height 1100mm, wall thickness 14mm, diameter 707mm, weight 475kg; the cemented carbide is a YG20 grade cemented carbide, the liner comprises a shell and a bottom plate 5, the shell is a small cylindrical surface 1, a small conical surface 2, a large conical surface 3, and a large cylindrical surface 4 connected in sequence from top to bottom, the bottom plate 5 is arranged at the bottom of the large cylindrical surface 4, and the liner is formed by the following integral pressing method, comprising the following steps:

[0091] Step 1: Assemble the mold. The mold is an assembled mold 13, including a square mandrel 10 and a four-petal inner mold fitted with four sides of the square mandrel 10. The four-petal inner molds are respectively a first petal inner mold 6, a second petal inner mold 7, and a third petal inner mold 8; a fourth petal inner mold 9. After the four-petal inner molds are assembled to the four sides of the square mandrel 10, the shape of the outer side surface thereof is adapted to the shell; first fix one end of the square mandrel 10 on the first plug 11, and then install the four-petal inner mold on the four sides of the square mandrel 10, put an elastic mold sleeve on the outer side of the four-petal inner mold, put a cemented carbide powder 14 between the elastic mold sleeve and the four-petal inner mold, and finally fix the other end of the square mandrel 10 with the second plug 12, thus completing the assembly of the pressing mold;

[0092] Step 2: Pressing: Put the mold filled with cemented carbide powder 14 into a dry bag cold isostatic press for pressing. When pressurizing, the circumference of the elastic mold sleeve is evenly compressed, and the two ends of the elastic mold sleeve are not compressed.

[0093] Step 3: demoulding, first take out the first plug 11 and the second plug 12, then take out the square mandrel 10 and the four-petal inner mold, and then take out the pressed inner shell from the elastic mold sleeve;

[0094] Step 4: Sintering: Sinter the pressed inner shell and the pre-sintered bottom plate 5 to obtain a large-capacity ball mill carbide inner shell.

[0095] In this comparative example, the bottom plate 5 is a disc-shaped structure. After pre-sintering, the diameter of the bottom plate 5 is 0.95 times the diameter of the inner cross section of the large cylindrical surface 4, that is, 671 mm, and the thickness is 15 mm.

[0096] In this comparative example, the cobalt content in the cemented carbide accounts for more than 10%.

[0097] In this comparative example, the pre-sintering is to put the pressed bottom plate 5 into a sintering furnace, heat it to 1385°C at a rate of 100°C every 10 minutes, keep it warm for 45 minutes, cool it naturally, and then take it out. After taking it out, it is necessary to polish the two planes, polish the inner hole with the plane as the reference, and ensure that the inner hole is perpendicular to the two end surfaces.

[0098] In this comparative example, the sintering process includes the following steps: (1) first filling the furnace with a vacuum; (2) raising the temperature by 100°C every 10 minutes to 1340°C for vacuum sintering; and keeping the temperature for 1.7 hours; (3) filling with argon gas at the end of the vacuum sintering, and carrying out argon-protected sintering at a temperature of 1400°C for 1.8 hours; (4) after the argon-protected sintering is completed, cooling naturally.

[0099] Experimental example:

[0100] The hardness, strength, grain size and service life of the six large-capacity ball mill hard alloy liners of Examples 1-6, the two large-capacity ball mill hard alloy liners of Comparative Example 1-2, and the existing 200L and 300L high manganese steel liners were tested, and the results are shown in the following table:

[0101]

[0102]

[0103] Note: The service life test uses YG10 carbide material with a ball-to-material ratio of 1:3. Conventional ball milling is performed for 48 hours. The wear rate of the inner liner before and after ball milling is observed. The liner is scrapped when the total wear rate reaches 60%, and the service life is calculated.

[0104] The present invention uses a mold designed for a large-capacity ball mill carbide liner with a special shape. The square core shaft 10 is combined with a four-petal inner mold to facilitate the installation and demolding of the mold. The liner shell is formed by pre-sintering the bottom plate 5 and then cold isostatic pressing. After assembly, they are sintered together, and finally the shell and the bottom plate 5 are completely fitted to achieve one-piece forming. Experiments have found that the large-capacity ball mill carbide liner made by this method has a longer service life than the same type of stainless steel liner and has higher rigidity.

[0105] Although the present invention has been described in detail above with specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A method for integrally pressing a large-capacity ball mill hard alloy liner with reinforcing ribs, characterized in that: The liner comprises a shell and a bottom plate, wherein the shell is a small cylindrical surface, a small conical surface, a large conical surface, and a large cylindrical surface connected in sequence from top to bottom, a bottom plate is arranged at the bottom of the large cylindrical surface, and more than two reinforcing ribs are arranged longitudinally and parallelly from top to bottom on the inner side of the large cylinder, and the method comprises the following steps: Step 1: Assemble the mold. The mold is an assembled mold, including a square mandrel and a four-petal inner mold fitted with the four sides of the square mandrel. After the four-petal inner mold is assembled to the four sides of the square mandrel, the shape of its outer side surface is adapted to the shell, and a groove structure adapted to the reinforcing rib is longitudinally parallelly arranged from top to bottom at the corresponding position of the lower end of the four-petal inner mold; first fix one end of the square mandrel on the first plug, then install the four-petal inner mold on the four sides of the square mandrel, put an elastic mold sleeve on the outer side of the four-petal inner mold, put cemented carbide powder between the elastic mold sleeve and the four-petal inner mold, and finally fix the other end of the square mandrel with the second plug to complete the assembly of the pressing mold; Step 2: Pressing: Place the mold filled with cemented carbide powder into a dry bag cold isostatic press for pressing. When pressurizing, the circumference of the elastic mold sleeve is evenly compressed, and the two ends of the elastic mold sleeve are not compressed; Step 3: demoulding: first remove the first plug and the second plug, then remove the square mandrel and the four-petal inner mold, and then remove the pressed inner shell from the elastic mold sleeve; Step 4: Sintering: Sinter the pressed inner shell and the pre-sintered bottom plate to obtain a large-capacity ball mill carbide inner shell with reinforced ribs.

2. The integral pressing method of a large-capacity ball mill hard alloy liner with reinforcing ribs according to claim 1 is characterized in that: The bottom plate is a disc-shaped structure, and the diameter of the bottom plate after pre-sintering is 0.85-0.95 times the diameter of the inner cross section of the large cylindrical surface.

3. The integral pressing method of a large-capacity ball mill hard alloy liner with reinforcing ribs according to claim 1 is characterized in that: The cemented carbide powder is a cemented carbide of grade YG10-YG25.

4. The integral pressing method of a large-capacity ball mill hard alloy liner with reinforcing ribs according to claim 1 is characterized in that: The content of cobalt and / or nickel in the cemented carbide powder is greater than 10%.

5. The integral pressing method of a large-capacity ball mill hard alloy liner with reinforcing ribs according to claim 1 is characterized in that: The pre-sintering is to put the pressed bottom plate into a sintering furnace, heat it to 1350° C.-1380° C., keep it warm for 40-50 minutes, and cool it down and take it out.

6. The method for integrally pressing and forming a large-capacity ball mill hard alloy liner according to claim 1, characterized in that: The sintering process comprises the following steps: (1) first filling the furnace with vacuum; (2) raising the temperature by 100°C every 10 minutes to 1300-1350°C for vacuum sintering; and keeping the temperature for 1.5-2.5 hours; (3) filling argon gas at the end of vacuum sintering, and carrying out argon protection sintering at a temperature of 1350-1450°C, and keeping the temperature for 1.5-2 hours; (4) after the argon protection sintering is completed, cooling naturally.

7. The method for integrally pressing and forming a large-capacity ball mill hard alloy liner according to claim 1, characterized in that: The capacity of the inner tank is 200 to 300L.

8. The method for integrally pressing and forming a large-capacity ball mill hard alloy liner according to claim 1, characterized in that: The inner diameter of the cross section of the large cylindrical surface is 620-707 mm.

9. The method for integrally pressing and forming a large-capacity ball mill hard alloy liner according to claim 1, characterized in that: The wall thickness of the inner container is 14 to 15 mm.

10. The method for integrally pressing and forming a large-capacity ball mill hard alloy liner according to claim 1, characterized in that: The weight of the inner container is 429-655 kg.

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