Mold and method for evaluating casting sand inclusion and sand burning defect risks caused by molding process

Abstract

The invention belongs to the technical field of casting molds, and particularly discloses a mold and method for evaluating casting sand inclusion and sand burning defect risks caused by a molding process, the mold comprises a guide-in block and a main body block, the guide-in block is fixedly connected to the left side of the main body block, the bottom of the guide-in block is an inclined plane, and the guide-in block is fixedly connected to the left side of the main body block. The thickness of the lead-in block is gradually increased from left to right; the main body block is of a step-shaped structure with a plurality of 90-degree corners, a plurality of bosses and grooves are formed in the side face of the main body block, and a plurality of grooves are formed in the bottom face of the main body block. After the mold is used for molding, the inclined surface at the bottom can increase the flow rate of molten metal, the bent mold main body is favorable for increasing the impact force of the molten metal on the sand mold wall, the boss and groove structures on the side surface and the bottom surface are weak mechanical property parts of the sand mold, and the capacity of the sand mold in molding, demolding, carrying and molten metal impact type external force resistance is detected; and rapid and accurate evaluation of casting sand inclusion and sand burning defect risks caused by the molding process is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of casting molds, and more specifically, relates to a mold and a method for evaluating the risk of sand inclusion and sand adhesion defects in castings caused by a molding process. Background Art

[0002] With the increasing attention paid to environmental protection and the working environment of workers, environmentally friendly molding sands such as self-hardening alkaline phenolic resin sand and inorganic silicate binder sand are replacing the original furan resin sand, phenol urethane resin sand and other highly polluting molding sands with high gas emission and harmful gas production. However, in actual applications, the use of environmentally friendly molding sands to produce castings is prone to sand inclusion and sand adhesion defects. These defects not only reduce the quality of castings, but also cause cracks and other defects. It may even directly scrap the castings, limiting the further application of environmentally friendly molding sands.

[0003] The main reason for the occurrence of sand inclusion and sand sticking defects is due to improper molding technology (i.e. the type and particle size of raw sand, the type and amount of binder added, the brushing process of coating, etc.), which weakens the ability of resin sand mold to resist external wear, collision and metal liquid impact. In actual production, this ability is difficult to evaluate and must be improved after actual casting production, which is time-consuming and labor-intensive. Summary of the invention

[0004] In view of the above defects or improvement needs of the prior art, the present invention provides a mold and method for evaluating the risk of sand inclusion and sand sticking defects in castings caused by the sand mold molding process, wherein the risk of sand inclusion and sand sticking defects in castings caused by the sand mold molding process is achieved quickly and accurately.

[0005] To achieve the above object, according to one aspect of the present invention, a mold for evaluating the risk of sand inclusion and sand sticking defects in castings caused by a molding process is provided, comprising an introduction block and a main body block, wherein:

[0006] The introduction block is fixedly connected to the left side of the main body block, and the bottom of the introduction block is an inclined surface, so that the thickness of the introduction block gradually increases from left to right;

[0007] The main body block is a stepped structure with several 90° corners, and several bosses and grooves are arranged on the side surface of the main body block, and several grooves are arranged on the bottom surface of the main body block.

[0008] As a further preferred embodiment, the main body block includes a first main body block and a second main body block, wherein the left side of the first main body block is connected to the import block, and the right side is connected to the second main body block; the bottom surface of the first main body block is a slope, and the slope is coplanar with the bottom slope of the import block to form an integral slope; the thickness of the second main body block remains unchanged, and its thickness is consistent with the thickness of the thickest part on the right side of the first main body block.

[0009] As a further preferred embodiment, a plurality of bosses and grooves are provided on the side surface of the first main body block, and a plurality of grooves are provided on the bottom surface of the second main body block.

[0010] As a further preferred embodiment, two bosses and two grooves are provided on the side surface of the first main body block, and two grooves are provided on the bottom surface of the second main body block.

[0011] As a further preference, for the boss or groove on the first main body block, the length and width of the cross section are both 12 to 20 mm.

[0012] As a further preference, the cross section of the boss or the groove on the first main body block is square.

[0013] As a further preference, the angle between the front side surface and the top surface of the introduction block is 100° to 120°.

[0014] As further preferred, the main body block is a stepped structure with three 90° corners.

[0015] As a further preferred embodiment, for the edges in the mold with an angle greater than 180°, a fillet with a radius of 5 mm is set; for the edges in the mold with an angle less than 180°, a fillet with a radius of 3 mm is set.

[0016] To achieve the above object, according to one aspect of the present invention, a mold for evaluating the risk of sand inclusion and sand adhesion defects in castings caused by molding process is proposed, comprising:

[0017] According to another aspect of the present invention, a method for evaluating the risk of sand inclusion and sand adhesion defects in castings caused by the molding process is provided, which is implemented using the above-mentioned mold and includes the following steps:

[0018] The mold is placed in a casting box and filled with molding sand prepared according to the molding process to be evaluated. After the sand mold is solidified to form a sand mold, the mold is taken out;

[0019] Pouring molten metal into the sand mold from one side of the introduction block position to form a casting;

[0020] Analyze the surface quality of each surface of the casting, and assess the risk of sand inclusion and sand adhesion in the molding sand based on the ratio of the number of surfaces with sand inclusion and sand adhesion defects to the total number of casting surfaces.

[0021] In general, the above technical solution conceived by the present invention has the following technical advantages compared with the prior art:

[0022] 1. The present invention can realize the rapid and accurate assessment of the risk of sand inclusion and sand adhesion defects of castings through the design of the introduction block and the main block through a miniaturized mold, thereby solving the problem that the impact and collision resistance of the existing casting molding process is difficult to evaluate; at the same time, it avoids the waste of molding raw materials and molten metal caused by risk assessment, reduces the input of manpower and materials, and the casting after pouring is light in weight, easy to carry and observe, which helps to reduce the damage to the surface quality of the casting during transportation and can achieve full-angle observation.

[0023] 2. The bottom of the mold is provided with a slope with a certain slope. Pouring from the thinnest side of the mold is beneficial to convert more potential energy into kinetic energy and increase the flow rate of the molten metal.

[0024] 3. The mold is equipped with a stepped main block with a 90° corner. If the angle is too large, the impact force of the molten metal on the mold wall will be insufficient, while if the angle is too small, it will be difficult to remove the mold.

[0025] 4. Grooves and bosses are designed on the sides of the mold, and grooves are designed on the bottom, which increases the concave-convex degree of the mold surface and can further increase the impact force on the mold wall.

[0026] 5. The angle between the front side and the top surface of the lead-in block is set to 100°~120°, which can make the molten metal flow smoothly into the cavity at a faster speed, so as to increase the impact force on the mold wall and the grooves and bosses. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of a mold structure for evaluating the risk of sand inclusion and sand adhesion defects in castings caused by the molding process according to an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of mold dimensions according to an embodiment of the present invention;

[0029] Figure 3 This is a detailed feature diagram of a mold according to an embodiment of the present invention;

[0030] Figure 4 It is a schematic diagram of a casting scheme according to an embodiment of the present invention.

[0031] In all the drawings, the same figure numbers are used to represent the same elements or structures, among which: 1-introduction block, 2-main block, 3-casting mold, 3-1-boss, 3-2-groove, 3-3-groove, 4-cross runner mold, 5-refractory brick, 6-sprue mold, 7-riser mold. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0033] The embodiment of the present invention provides a mold for evaluating the risk of sand inclusion and sand sticking defects in castings caused by the molding process. The mold is used to evaluate the risk of sand inclusion and sand sticking defects in castings caused by the molding process. Therefore, during the design process, it is required that the mold can increase the metal flow rate and increase the impact force of the metal liquid on the sand mold wall. There are also some parts that are prone to sand inclusion and sand sticking defects. Figure 1 and Figure 3 As shown, the mold includes an introduction block 1 and a main body block 2, wherein:

[0034] The lead-in block 1 is fixedly connected to the left side of the main block 2, and the bottom of the lead-in block 1 is a slope. The thickness of the lead-in block 1 gradually increases from left to right. As the distance from the pouring inlet increases, the internal space of the mold becomes larger, which is conducive to the flow of the molten metal and increases the flow rate of the molten metal.

[0035] The main block 2 is a stepped structure with several 90° corners, which can increase the impact of the molten metal on the casting and facilitate inspection. Several bosses and grooves are provided on the side of the main block 2, and several grooves are provided on the bottom of the main block 2. These parts are the mechanical weak points of the sand mold after molding, and the molten metal will directly impact these parts, which is conducive to testing the ability of the sand mold to resist external collision, friction and molten metal impact during demoulding, transportation, box assembly and pouring.

[0036] Furthermore, the main body block 2 includes a first main body block and a second main body block, wherein the first main body block is connected to the introduction block 1 on the left side and to the second main body block on the right side; the bottom surface of the first main body block is a slope, and the slope is coplanar with the bottom slope of the introduction block 1 to form an integral slope, that is, the introduction block 1 and the first main body block form a whole, and its thickness gradually increases from left to right; the thickness of the second main body block remains unchanged, and its thickness is consistent with the thickness of the thickest part on the right side of the first main body block.

[0037] Furthermore, the first main body block is provided with a plurality of bosses 3-1 and grooves 3-2 on the side surface, and the second main body block is provided with a plurality of grooves 3-3 on the bottom surface, so as to test the performance of various casting structures. In this embodiment, the main body block 2 is a stepped structure with three 90° corners, and the bosses 3-1, grooves 3-2, and grooves 3-3 are all provided with two; preferably, the two grooves 3-1 are provided on two opposite sides of the first main body block, and the two bosses 3-2 are also provided on two opposite sides of the first main body block; and the two grooves 3-3 are provided on both sides of the bottom surface of the second main body block.

[0038] Furthermore, the length and width of the cross section of the boss 3-1 or the groove 3-2 are both 12 to 20 mm, and the cross section is preferably a square with equal length and width, so that the mechanical properties of the groove and the boss are moderate, expanding the applicability of the evaluation of the molding process scheme; the height of the boss 3-1 and the groove 3-2 (i.e., the mold thickness direction) is 80% to 100% of the length of the surface on which it is located.

[0039] Furthermore, the included angle between the front side surface and the top surface of the introduction block 1 is 100° to 120°.

[0040] Furthermore, the mold is designed with rounded corners: for edges with an angle greater than 180 degrees, the rounded corner radius is set to 5mm, and for edges with an angle less than 180 degrees, the rounded corner radius is set to 3mm. This is to facilitate demolding and help reduce the 90° edges of the sand mold from being too fragile and damaged by impact. After the edges of the mold with an angle greater than 180° are completed, the corresponding edges of the sand mold are less than 90°, so the rounded corners should be set larger.

[0041] A method for evaluating the risk of sand inclusion and sand adhesion defects in castings caused by a molding process provided by an embodiment of the present invention is implemented based on the above-mentioned mold and includes the following steps:

[0042] The mold is placed in a casting box and filled with the molding sand to be evaluated (i.e., the molding sand prepared according to the molding process to be evaluated). After the sand mold is solidified to form a sand mold, the mold is taken out;

[0043] Pouring molten metal into the sand mold from one side of the introduction block position to form a casting;

[0044] Analyze the surface quality of each surface of the casting, and assess the risk of sand inclusion and sand adhesion in the sand mold based on the ratio of the number of surfaces with sand inclusion and sand adhesion defects to the total number of casting surfaces.

[0045] More specifically, the following steps are included:

[0046] S1, made as Figure 2 The dimensions shown are used to make a casting mold 3 and other molding molds for evaluating the risk of sand inclusion and sand sticking defects in the casting caused by the molding process, including a sprue mold 6, a runner mold 4, and a riser mold 7.

[0047] S2, mixing the sand within the usable time at a certain temperature and humidity according to the molding process to be evaluated, to obtain the mixed molding sand to be evaluated.

[0048] S3, place the casting mold 3 and the runner mold 4 in the lower box, the runner mold is placed at the thinnest part of the casting mold in the longitudinal direction, the upper surface of the runner mold and the upper surface of the casting mold are flush with the parting surface, and place refractory bricks 5 at the bottom of the runner to reduce the direct impact of the molten metal on the runner and reduce the influence of other factors, and fill in the molding sand mixed in step S1.

[0049] S4, placing the sprue mold 6 and the riser mold 7 in the upper box, the bottom of the sprue mold fits the upper surface of the runner, the upper end of the sprue has a large cross-section and the lower end has a small cross-section, which is conducive to pouring and increasing the impact speed of the molten metal. The riser is set at the farthest end from the pouring inlet and filled with the molding sand mixed in step S1.

[0050] S5, after the sand mold is solidified, the casting mold 3, the runner mold 4, the sprue mold 6, and the riser mold 7 are taken out, and the refractory bricks 5 remain fixed in the sand mold.

[0051] S6, paint the runner, sprue, riser, and the contact area between the upper box and the casting mold to reduce the impact of these parts on the result. The remaining parts that are completed by the casting mold do not need to be painted.

[0052] S7, pouring molten metal, after the casting solidifies, take out the casting and cool it, then perform sand removal and shot blasting; after pouring, the casting weighs more than 6kg (steel casting), which is conducive to modeling and observation, and consumes less molten metal and modeling materials.

[0053] S8, observe the typical parts of the casting, including the plane and inclined surface of the bottom, the three surfaces of the two bosses on the side, the four surfaces of the two grooves on the side, the four surfaces of the two grooves on the bottom, and a total of 24 surfaces on both sides, analyze the roughness, sand inclusion and sand adhesion defects of the casting, and record the number of surfaces with sand inclusion and sand adhesion defects among the 24 surfaces.

[0054] S9, the percentage of the number of surfaces with sand inclusion and sand adhesion defects divided by the total number of surfaces (24) is used to assess the risk of sand inclusion and sand adhesion caused by the modified process.

[0055] In summary, the mold and risk assessment method provided by the present invention not only solve the problem that the risk of sand inclusion and sand sticking defects caused by the molding process cannot be assessed, which leads to actual defects in the casting, but also the mold is miniaturized and easy to operate, and is therefore particularly suitable for application scenarios where the risk assessment of sand inclusion and sand sticking defects caused by the sand casting molding process is required.

[0056] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A mold for evaluating the risk of sand inclusion and sand sticking defects in castings caused by molding process, characterized in that: It includes an import block (1) and a main block (2), wherein: The introduction block (1) is fixedly connected to the left side of the main body block (2), and the bottom of the introduction block (1) is an inclined surface, so that the thickness of the introduction block (1) gradually increases from left to right; The main body block (2) is a stepped structure with several 90° corners, and the side surface of the main body block (2) is provided with several bosses and grooves, and the bottom surface of the main body block (2) is provided with several grooves.

2. The mold for evaluating the risk of sand inclusion and sand adhesion defects in castings caused by the molding process as claimed in claim 1, characterized in that: The main body block (2) comprises a first main body block and a second main body block, wherein the first main body block is connected to the introduction block (1) on the left side and connected to the second main body block on the right side; the bottom surface of the first main body block is an inclined surface, and the inclined surface is coplanar with the bottom inclined surface of the introduction block (1) to form an integral inclined surface; the thickness of the second main body block remains unchanged, and its thickness is consistent with the thickness of the thickest part of the right side of the first main body block.

3. The mold for evaluating the risk of sand inclusion and sand sticking defects in castings caused by the molding process as claimed in claim 2, characterized in that: The side surface of the first main body block is provided with a plurality of bosses and grooves, and the bottom surface of the second main body block is provided with a plurality of grooves.

4. The mold for evaluating the risk of sand inclusion and sand sticking defects in castings caused by the molding process as claimed in claim 3, characterized in that: The side surface of the first main body block is provided with two bosses and two grooves, and the bottom surface of the second main body block is provided with two grooves.

5. The mold for evaluating the risk of sand inclusion and sand adhesion defects in castings caused by the molding process as claimed in claim 3, characterized in that: For the boss or groove on the first main body block, the length and width of the cross section are both 12 to 20 mm.

6. The mold for evaluating the risk of sand inclusion and sand adhesion defects in castings caused by the molding process as claimed in claim 3, characterized in that: The cross section of the boss or the groove on the first main body block is a square.

7. The mold for evaluating the risk of sand inclusion and sand adhesion defects in castings caused by molding process as claimed in claim 1, characterized in that: The included angle between the front side surface and the top surface of the introduction block (1) is 100° to 120°.

8. The mold for evaluating the risk of sand inclusion and sand adhesion defects in castings caused by molding process as claimed in claim 1, characterized in that: The main body block (2) is a stepped structure with three 90° corners.

9. The mold for evaluating the risk of sand inclusion and sand adhesion defects in castings caused by the molding process according to any one of claims 1 to 8, characterized in that: For the edges in the mold with an angle greater than 180°, a fillet with a radius of 5 mm is set; for the edges in the mold with an angle less than 180°, a fillet with a radius of 3 mm is set.

10. A method for evaluating the risk of sand inclusion and sand adhesion defects in castings caused by molding process, implemented by using the mold according to any one of claims 1 to 9, characterized in that: The steps include: The mold is placed in a casting box and filled with molding sand prepared according to the molding process to be evaluated. After the sand mold is solidified to form a sand mold, the mold is taken out; Pouring molten metal into the sand mold from one side of the introduction block position to form a casting; Analyze the surface quality of each surface of the casting, and assess the risk of sand inclusion and sand adhesion in the molding sand based on the ratio of the number of surfaces with sand inclusion and sand adhesion defects to the total number of casting surfaces.

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