A cylinder liner plate for a semi-autogenous mill and a casting method thereof

Abstract

The application relates to a cylinder lining plate for a semi-autogenous mill and a casting method thereof, and belongs to the technical field of steel metallurgy. The cylinder lining plate for the semi-autogenous mill comprises the following components in percentage by mass: Fe 82.67-86.9%, C 0.9-1.3%, Si 0.3-0.7%, Mn 10-13%, Cr 1.8-2.5%, and impurities in balance. The application greatly reduces the defects such as shrinkage cavity, shrinkage porosity and inclusion of the cylinder lining plate by optimizing the composition of the cylinder lining plate, optimizing the heat treatment process and the process parameters, and improving the structure design of the lost foam, and the service life of the cylinder lining plate is improved to 5-6 months, so that the replacement frequency of the cylinder lining plate is reduced, and the production cost is saved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steel alloy smelting, and particularly relates to a cylinder liner plate for a semi-autogenous mill and a casting method thereof. BACKGROUND

[0002] The semi-autogenous mill is a widely used ore grinding equipment in the mining industry, and the cylinder liner plate is an important component of the semi-autogenous mill, which mainly lifts the ore and protects the main structure of the semi-autogenous mill. The cylinder liner plate is subjected to the combined action of impact, grinding and ore slurry corrosion for a long time, and is seriously consumed. People have conducted extensive research on the wear process of the cylinder liner plate. For the semi-autogenous mill, if the inspection is not timely, the cylinder liner plate may fall off due to excessive wear, which not only damages the main structure but also has a large safety hazard. However, if the cylinder liner plate is replaced too early, it will be a waste.

[0003] The cylinder liner plate of the existing semi-autogenous mill has many shrinkage porosity defects, and has a short service life, generally not more than 4 months. During use, the liner plate often cracks or even partially falls off, and needs to be frequently replaced, which is high in production cost and has a huge safety production hazard.

[0004] Therefore, it is necessary to optimize and improve the cylinder liner plate to prolong its service life and achieve the purpose of reducing cost and increasing efficiency. SUMMARY

[0005] The present application aims at overcoming the shortcomings of the prior art and providing a cylinder liner plate for a semi-autogenous mill and a casting method thereof.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0007] In the first aspect, the present application provides a cylinder liner plate for a semi-autogenous mill, which comprises the following components in mass percentage: Fe 82.67-86.9%, C 0.9-1.3%, Si 0.3-0.7%, Mn 10-13%, Cr 1.8-2.5%, and impurities in the balance.

[0008] Preferably, the cylinder liner plate for the semi-autogenous mill comprises the following components in mass percentage: Fe 84.2-84.4%, C 1.0-1.2%, Si 0.5-0.6%, Mn 11-12%, Cr 1.9-2.0%, and impurities in the balance.

[0009] In the second aspect, the present application provides a casting method of the cylinder liner plate for the semi-autogenous mill as described in the first aspect, which comprises the following steps:

[0010] S1, mixing and heating each component to obtain a metal melt;

[0011] S2, pouring the metal melt obtained in step S1 into a sand box provided with a lost pattern in advance, and obtaining a liner cast by cooling and cleaning;

[0012] S3, performing heat treatment on the liner cast, and obtaining the mill cylinder liner by water toughening treatment.

[0013] Preferably, in step S1, the temperature of the heating and smelting is 1500-1600℃.

[0014] Preferably, in step S2, the temperature of the metal melt is 1400-1500℃, and the vacuum degree in the sand box is -0.08MPa to -0.02MPa.

[0015] In step S2, the metal melt is poured into the sand box provided with the lost pattern in advance until the metal melt fills the riser of the lost pattern.

[0016] Preferably, in step S2, in the sand box provided with the lost pattern in advance, the lost pattern comprises a cylinder liner pattern, a sprue, a gate and a riser, the cylinder liner pattern, the sprue and the riser are located in the sand box, the gate is located outside the sand box, the sprue is connected with the gate, the structure of the cylinder liner pattern is the same as that of the semi-autogenous mill cylinder liner, the cylinder liner pattern has a first side and a second side, the first side is opposite to the second side, the first side is connected with the sprue, the second side is connected with the riser, the direction of the cylinder liner pattern from the first side to the second side is upwardly inclined, the cylinder liner pattern comprises a liner body, and the included angle between the liner body and the inner bottom surface of the sand box is α, and α is 5-15°.

[0017] The inventor has found through research that the inclined arrangement of the cylinder liner pattern in the sand box can effectively promote the full feeding of liquid metal to the solidification shrinkage of each part of the casting, improve the surface quality of the cylinder liner and reduce the internal shrinkage cavity and shrinkage porosity defects of the cylinder liner.

[0018] Further preferably, the cylinder liner pattern further comprises a lifting strip and a plurality of reinforcing ribs, the lifting strip extends along the length direction of the liner body, one side of the reinforcing rib is connected with the lifting strip, the other side of the reinforcing rib extends along the surface of the liner body, the plurality of reinforcing ribs are parallel and equally spaced along the length direction of the liner body, and the number of the risers is two, one of the risers corresponds to the reinforcing rib at the leading end, and the other riser corresponds to the reinforcing rib at the trailing end.

[0019] The inventor has found through research that the arrangement of one riser on each side of the reinforcing rib at the leading end and the trailing end facilitates the feeding of the metal melt to the cylinder liner and the subsequent cutting. The combination of the double-riser design and the inclined arrangement of the cylinder liner pattern can better improve the surface quality of the liner and reduce the internal shrinkage cavity and shrinkage porosity defects of the liner.

[0020] Preferably, the cooling method in step S2 comprises: firstly naturally cooling to a temperature not greater than 200 DEG C, and then opening the box and air cooling to a temperature not greater than 40 DEG C.

[0021] Preferably, step S3 specifically comprises: heating the liner casting to 350-500 DEG C at a rate of 125-200 DEG C / h, heating from 350-500 DEG C to 600-750 DEG C at a rate of 100-175 DEG C / h, keeping at 600-750 DEG C for 0.5-2 h, heating from 600-750 DEG C to 950-1100 DEG C at a rate of 150-200 DEG C / h, keeping at 950-1100 DEG C for 2-4 h, heating from 950-1100 DEG C to 1050-1200 DEG C at a rate of 75-150 DEG C / h, and keeping at 1050-1200 DEG C for 1-3 h.

[0022] Further preferably, step S3 specifically comprises: heating the liner casting to 400-450 DEG C at a rate of 150-175 DEG C / h, heating from 400-450 DEG C to 650-700 DEG C at a rate of 125-150 DEG C / h, keeping at 650-700 DEG C for 1-1.5 h, heating from 650-700 DEG C to 1000-1050 DEG C at a rate of 160-180 DEG C / h, keeping at 1000-1050 DEG C for 2.5-3 h, heating from 1000-1050 DEG C to 1100-1150 DEG C at a rate of 100-125 DEG C / h, and keeping at 1100-1150 DEG C for 1.5-2 h.

[0023] Preferably, the water temperature of the water toughening treatment is 40-50 DEG C, and the time is not greater than 30 s.

[0024] Compared with the prior art, the application has the beneficial effects that:

[0025] The application greatly reduces the shrinkage holes, shrinkage porosity and inclusions of the liner of the cylinder, improves the service life of the liner of the cylinder to 5-6 months, thereby reducing the replacement frequency of the liner of the cylinder and saving production cost. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a perspective view of the placement of the lost foam in the sand box;

[0027] Figure 2 is a schematic view of the placement of the lost foam in the sand box;

[0028] Figure 3 is a perspective view of the liner of the cylinder;

[0029] Figure 4 is a schematic view of the assembly structure of the liner of the cylinder.

[0030] In the figure, 1 - sprue, 2 - runner, 21 - straight runner, 22 - cross runner, 23 - inner runner, 3 - barrel lining mold, 31 - lining body, 32 - lifting strip, 33 - reinforcing rib, 4 - riser, 5 - sand box. DETAILED DESCRIPTION

[0031] In order to better illustrate the purpose, technical scheme and advantages of the present application, the present application will be further described below in combination with specific examples.

[0032] Example 1

[0033] The barrel lining for semi-autogenous mill and the casting method thereof according to the present application, the barrel lining for semi-autogenous mill comprises the following components with mass percentage: Fe 84.4%, C 1.0%, Si 0.5%, Mn 12%, Cr 2.0%, impurities balance, S < 0.07%, P < 0.06%.

[0034] The casting method of the barrel lining for semi-autogenous mill, comprising the following steps:

[0035] S1, mixing and heating each component to 1550℃, smelting to form a metal melt;

[0036] S2, cooling the obtained metal melt to 1440℃, under the condition of vacuumizing to -0.05MPa, pouring the metal melt with temperature of 1440℃ into the sand box 5 provided with the lost form in advance, until the metal melt fills the riser of the lost form, after pouring is completed, naturally cooling to 200℃, opening the box and air cooling to room temperature (25℃) for cleaning to remove the sprue 1, the runner 2 and the riser 4, to obtain the lining castings;

[0037] The lost form comprises the barrel lining mold, the runner 2, the sprue 1 and the riser 4, the barrel lining mold, the runner 2 and the riser 4 are located in the sand box 5, the sprue 1 is located outside the sand box 5, the runner 2 is connected with the sprue 1, the structure of the barrel lining mold 3 is the same as that of the barrel lining for semi-autogenous mill, the barrel lining mold 3 has a first side and a second side, the first side is opposite to the second side, the first side is connected with the runner 2, the second side is connected with the riser 4, the direction of the barrel lining 3 from the first side to the second side is upwardly inclined, the barrel lining mold 3 comprises a lining body 31, the included angle between the lining body 31 and the inner bottom surface of the sand box 5 is α, and α is 10°.

[0038] The sleeve lining mold 3 further comprises a lifting strip 32 and three reinforcing ribs 33, the lifting strip 32 and the reinforcing ribs 33 are arranged on the side surface of the lining body 31 away from the sand box 5, the lifting strip 32 extends along the length direction of the lining body 31, one side of the reinforcing rib 33 is connected with the lifting strip 32, the other side of the reinforcing rib 33 extends along the surface of the lining body 31, and the three reinforcing ribs 33 are parallel and equidistantly distributed along the length direction of the lining body 31; the number of the risers 4 is two, one of the risers 4 corresponds to the reinforcing rib 33 at the head end, and the other of the risers 4 corresponds to the reinforcing rib 33 at the tail end.

[0039] The sprue 2 comprises a straight sprue 21, a cross sprue 22 and an inner sprue 23, the first side of the sleeve lining mold is connected with one end of the inner sprue 23, the other end of the inner sprue 23 is connected with the cross sprue 22, the cross sprue 22 is connected with the lower end of the straight sprue 21, and the upper end of the straight sprue 21 is connected with the gate 1;

[0040] S3, heat treating the lining castings, the heat treatment comprising the following processes: heating from 25℃ to 400℃ at a rate of 150℃ / h, heating from 400℃ to 650℃ at a rate of 125℃ / h, keeping at 650℃ for 1h, heating from 650℃ to 1050℃ at a rate of 160℃ / h, keeping at 1050℃ for 3h, heating from 1050℃ to 1100℃ at a rate of 100℃ / h, keeping at 1100℃ for 1.5h;

[0041] Immediately after the heat treatment, water toughening treatment is performed, the water entering time is 20s, the water temperature is controlled to be 40-50℃ through circulating water cooling, and the sleeve lining is obtained through natural aging.

[0042] Examples 2-3 and Comparative Examples 1-5

[0043] Examples 2-3 and Comparative Examples 1-5 are different from Example 1 in that, in Example 2, α is 5°, in Example 3, α is 15°, in Comparative Example 1, α is 0° (i.e. the sleeve lining mold is placed horizontally), in Comparative Example 2, α is 3°, in Comparative Example 3, α is 20°, in Comparative Example 4, the lost mold is not provided with risers, and in Comparative Example 5, the number of the risers is one, and the lower end of the riser is connected with the side surface of the middle one of the three reinforcing ribs 33.

[0044] Examples 4-6

[0045] Examples 4-6 are different from Example 1 in that:

[0046] In Example 4, the barrel liner for the semi-autogenous mill comprises the following components by mass percentage: Fe 83.2%, C 1.2%, Si 0.6%, Mn 11%, Cr 1.9%, balance impurities, the mass percentage of S in the barrel liner <0.07%, the mass percentage of P <0.06%;

[0047] In Example 5, the barrel liner for the semi-autogenous mill comprises the following components by mass percentage: Fe 82.67%, C 1.3%, Si 0.7%, Mn 12.8%, Cr 2.5%, balance impurities, the mass percentage of S in the barrel liner <0.07%, the mass percentage of P <0.06%;

[0048] In Example 6, the barrel liner for the semi-autogenous mill comprises the following components by mass percentage: Fe 86.9%, C 0.9%, Si 0.3%, Mn 10%, Cr 1.8%, balance impurities, the mass percentage of S in the barrel liner <0.07%, the mass percentage of P <0.06%.

[0049] Examples 7-9 and Comparative Examples 6-8

[0050] Examples 7-9 and Comparative Examples 6-8 differ from Example 1 in that:

[0051] In Example 7, the heat treatment comprises the following process: heating from 25°C to 450°C at a rate of 175°C / h, heating from 450°C to 700°C at a rate of 150°C / h, holding at 700°C for 1.5h, heating from 700°C to 1050°C at a rate of 180°C / h, holding at 1050°C for 3h, heating from 1050°C to 1150°C at a rate of 125°C / h, holding at 1150°C for 2h;

[0052] In Example 8, the heat treatment comprises the following process: heating from 25°C to 350°C at a rate of 125°C / h, heating from 350°C to 600°C at a rate of 100°C / h, holding at 600°C for 2h, heating from 600°C to 950°C at a rate of 150°C / h, holding at 950°C for 4h, heating from 950°C to 1050°C at a rate of 75°C / h, holding at 1050°C for 3h;

[0053] In Example 9, the heat treatment comprises the following process: heating from 25°C to 500°C at a rate of 200°C / h, heating from 500°C to 750°C at a rate of 175°C / h, holding at 750°C for 0.5h, heating from 750°C to 1100°C at a rate of 200°C / h, holding at 1100°C for 2h, heating from 1100°C to 1200°C at a rate of 150°C / h, holding at 1200°C for 1h;

[0054] In the comparative example 6, the heat treatment comprises the following process: heating from 25℃ to 1100℃ at a rate of 150℃ / h, keeping at 1100℃ for 6h;

[0055] In the comparative example 7, the heat treatment comprises the following process: heating from 25℃ to 650℃ at a rate of 150℃ / h, heating from 650℃ to 1050℃ at a rate of 160℃ / h, keeping at 1050℃ for 3h, heating from 1050℃ to 1100℃ at a rate of 100℃ / h, keeping at 1100℃ for 1.5h;

[0056] In the comparative example 8, the heat treatment comprises the following process: heating from 25℃ to 400℃ at a rate of 150℃ / h, heating from 400℃ to 650℃ at a rate of 125℃ / h, keeping at 650℃ for 1h, heating from 650℃ to 1100℃ at a rate of 160℃ / h, keeping at 1100℃ for 4.5h.

[0057] Each of the examples and the comparative examples made the cylinder liner samples of the same specification, and then the following tests were conducted:

[0058] The cylinder liner was used in the mill to process materials, and the specification of the semi-autogenous mill was Φ5.8m×1.8m. From the date of use of the mill, the daily processing capacity was 3000t / d, until the cylinder liner could not be used and was disassembled, the date of use of the cylinder liner and the date of disassembly were recorded, the interval time from the date of use to the date of disassembly was calculated, and the interval time was the service life of the cylinder liner; the number of samples was 9, and the average value was calculated.

[0059] The results are shown in Tables 1-2 below.

[0060] Table 1

[0061]

[0062] Table 2

[0063]

[0064] From the examples 1-9, it can be seen that by optimizing the composition of the cylinder liner, optimizing the parameters of the casting and heat treatment processes, and improving the structure design of the lost foam, the shrinkage holes, shrinkage porosity, inclusions and other defects of the cylinder liner are greatly reduced, and the service life of the cylinder liner is improved to 5-6 months, thereby reducing the replacement frequency of the cylinder liner and saving production costs.

[0065] From the examples 1-3 and the comparative examples 1-5, it can be seen that the present application can provide sufficient metal liquid to supplement the liquid shrinkage and solidification shrinkage of the casting by setting the cylinder liner mold at a proper angle in the sand box and setting the riser at the side corresponding to the head end reinforcing rib and the side corresponding to the tail end reinforcing rib, respectively, has good feeding effect, greatly reduces the shrinkage cavity and shrinkage porosity defects in the cylinder liner, improves the surface quality of the cylinder liner, and further significantly improves the service life of the cylinder liner.

[0066] From the examples 1, 7-9 and the comparative examples 6-8, it can be seen that the present application can prevent the liner from having a cracking tendency during heating by the heat treatment process of specific stage heating and stage holding, can more effectively dissolve carbide and pearlite, and improves the service life of the liner.

[0067] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A casting method of a liner plate for a shell of a semi-autogenous mill, characterized by, Comprise the following quality percentage of components: Fe 83.2~84.4%, C 1.0~1.2%, Si 0.5~0.6%, Mn 11~12%, Cr 1.9~2.0%, impurities balance; The casting method of the cylinder liner for the semi-autogenous mill comprises the following steps: S1, each component is mixed, heated and melted to obtain a metal melt; S2, the metal melt is poured into a sand box provided with a lost form in advance, and after cooling and cleaning, a liner casting is obtained; S3, the liner casting is heat treated, and after water toughening treatment, the cylinder liner for the mill is obtained; In step S1, the temperature of the heating and melting is 1500~1600℃; In step S2, when pouring, the temperature of the metal melt is 1400~1500℃, and the vacuum degree in the sand box is-0.08MPa~-0.02MPa; In step S2, in the sand box provided with a lost form in advance, the lost form comprises a cylinder liner form, a sprue, a gate and a riser, the cylinder liner form, the sprue and the riser are located in the sand box, the gate is located outside the sand box, the sprue is connected with the gate, the structure of the cylinder liner form is the same as that of the cylinder liner for the semi-autogenous mill, the cylinder liner form has a first side and a second side, the first side is opposite to the second side, the first side is connected with the sprue, the second side is connected with the riser, the direction of the cylinder liner from the first side to the second side is upwardly inclined, and the cylinder liner comprises a liner body, and the included angle between the liner body and the inner bottom surface of the sand box is α, and α is 5~15°.

2. The casting method of the liner plate for a mill shell of a semi-autogenous mill according to claim 1, characterized by, The cylinder liner form comprises a liner body, a lifting strip and a plurality of reinforcing ribs, the lifting strip extends along the length direction of the liner body, one side of the reinforcing rib is connected with the lifting strip, the other side of the reinforcing rib extends along the surface of the liner body, a plurality of reinforcing ribs are distributed in parallel and at equal intervals along the length direction of the liner body, and the number of the risers is two, one riser corresponds to the reinforcing rib located at the head end, and the other riser corresponds to the reinforcing rib located at the tail end.

3. The casting method of the liner plate for a mill shell of a semi-autogenous mill according to claim 1, characterized by, The cooling method in step S2 comprises: natural cooling to a temperature not greater than 200℃, and then opening the box for air cooling to a temperature not greater than 40℃.

4. The casting method of the liner plate for a mill shell of a semi-autogenous mill according to claim 1, characterized by, Step S3 specifically comprises: heating at a rate of 125~200℃ / h to 350~500℃, heating from 350~500℃ to 600~750℃ at a rate of 100~175℃ / h, keeping at 600~750℃ for 0.5~2h, heating from 600~750℃ to 950~1100℃ at a rate of 150~200℃ / h, keeping at 950~1100℃ for 2~4h, heating from 950~1100℃ to 1050~1200℃ at a rate of 75~150℃ / h, and keeping at 1050~1200℃ for 1~3h.

5. The casting method of the liner plate for the mill shell of a semi-autogenous mill according to claim 1, characterized by, The water temperature of the water toughening treatment is 40~50℃, and the time is not greater than 30s.

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