Anti-crack pouring method for complex structure cast steel

Abstract

The application relates to a crack-preventing pouring method for a complex structure cast steel piece, which comprises the following steps: S1, structure design of a pre-embedded crack-preventing rib sand core; S2, preparation of the pre-embedded crack-preventing rib sand core; S3, preparation of a cast steel piece sand mold; and S4, pouring of the cast steel piece. The pre-embedded crack-preventing rib sand core is arranged at any position prone to cracks of the steel casting, so that a crack-preventing rib is additionally arranged, the crack-preventing rib is prearranged through the pre-embedded crack-preventing rib sand core, and is not limited by the size and structure difficulty of the product; the crack-preventing rib sand core is made of special sand, and the use amount of the special sand can be accurately controlled, so that the positions prone to cracks are accurately chilled, and the produced product cannot appear cracks again. The complex structure cast steel piece processed by the application has stable performance, is not prone to cracks, and has a long service life.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of casting production of castings, in particular to a crack prevention pouring method for a cast steel piece with a complex structure. BACKGROUND

[0002] The existing cast steel piece with a complex structure is prone to cracks caused by stress concentration during the cooling and solidification process after pouring molten steel due to the complex structure, uneven wall thickness of the product, and unsmooth transition between thick and thin walls. Removing these cracks requires rework, resulting in increased production costs. The existing method to solve these cracks caused by stress is to add a crack prevention rib. However, due to the complex structure of the product, the conventional crack prevention rib is affected by the product structure and cannot achieve the expected effect, i.e., the crack prevention rib added to the shape and internal cavity cannot completely remove the cracks of the product. Moreover, the shape of the crack prevention rib is easily limited, and it is inconvenient to place and install. At the same time, special sand cannot be placed quantitatively in complex parts to further accelerate cooling, and the crack prevention effect is limited. SUMMARY

[0003] The present application relates to the technical field of casting production of castings, in particular to a crack prevention pouring method for a cast steel piece with a complex structure.

[0004] The object of the present application can be achieved by the following technical solutions:

[0005] A crack prevention pouring method for a cast steel piece with a complex structure, comprising the following steps:

[0006] S1, structure design of pre-embedded crack prevention rib sand core: according to the structure and material of the cast steel piece, and using computer simulation software, the shape and size of the crack prevention rib sand core are determined, and the size of the crack prevention rib core box is determined;

[0007] S2, preparation of pre-embedded crack prevention rib sand core: using resin self-hardening sand as raw material, and selecting a sand box with appropriate size, a crack prevention rib core box mold is manufactured; the surface of the crack prevention rib core box mold is coated, polished and brushed with a release agent, and then special sand is used to seed sand in the crack prevention rib core box mold, and finally the pre-embedded crack prevention rib sand core is obtained by demolding;

[0008] S3, preparation of cast steel piece sand mold: selecting a sand box with appropriate size, placing the cast steel piece mold, and placing the pre-embedded crack prevention rib sand core at the position where the crack prevention rib is needed on the cast steel piece mold; then filling sand in the sand box with resin self-hardening sand as raw material, and finally demolding after hardening to obtain a cast steel piece sand mold with pre-embedded crack prevention rib sand core;

[0009] S4, pouring of cast steel piece: pouring molten steel into the cast steel piece sand mold with pre-embedded crack prevention rib sand core, thereby obtaining a complex structure cast steel piece with crack prevention based on pre-embedded crack prevention rib.

[0010] Preferably, in the step S3 of preparing the sand mold of the cast steel piece, the previously prepared anti-cracking rib is placed in the pre-embedded anti-cracking rib sand core, and then the step S4 of pouring the cast steel piece is performed to obtain the complex structure cast steel piece capable of preventing cracks and having the pre-embedded anti-cracking rib.

[0011] Preferably, in the step S3 of preparing the sand mold of the cast steel piece, the previously prepared anti-cracking rib is placed in the pre-embedded anti-cracking rib sand core, and then the step S4 of pouring the cast steel piece is performed to obtain the complex structure cast steel piece capable of preventing cracks and having the pre-embedded anti-cracking rib.

[0012] Preferably, in the step S2, the influencing factors of the usage amount of the special sand of the pre-embedded anti-cracking rib sand core include the original mold number M0 of the cast steel piece, the equivalent mold number M1 of the cast steel piece after using the special sand, a coefficient n, the thickness of the chilling area cast piece, and the strength of the sand core.

[0013] Preferably, in the step S2, the calculation formula of the usage amount of the special sand of the pre-embedded anti-cracking rib sand core is: C1 =(A S -A0) / n=(V0 / M1-V0 / M0) / n=V0(M0-M1) / n*M0*M1; wherein A C1 is the working surface area of the special sand; A S is the equivalent area of the sand mold; A0 is the surface area of the chilling area cast piece; M0 is the original mold number of the cast piece; M1 is the equivalent mold number of the cast piece after using the special sand; V0 is the volume of the cast piece; and n is a coefficient determined according to the thickness of the chilling area.

[0014] Preferably, the coefficient n is determined according to the thickness of the chilling area, and is generally 0.2-1.0.

[0015] Preferably, the thickness of the pre-embedded anti-cracking rib sand core is determined according to the thickness of the chilling area and the strength of the sand core, and is generally 1-5 times the thickness of the chilling area.

[0016] Advantages of the present application:

[0017] The anti-crack pouring method of the complex structure cast steel piece of the present application sets the pre-embedded anti-cracking rib sand core at any part of the steel cast piece prone to cracks, thereby adding the anti-cracking rib, which is pre-set by the pre-embedded anti-cracking rib sand core and is not limited by the size and structure difficulty of the product. The anti-cracking rib sand core is made of special sand, and the usage amount of the special sand can be accurately controlled, thereby accurately chilling the parts prone to cracks and ensuring that the produced product will not have cracks. The complex structure cast steel piece processed by the present application has stable performance, is not prone to cracks, and has a long service life. DETAILED DESCRIPTION

[0018] For the convenience of those skilled in the art to understand, the application will be further described below in conjunction with specific embodiments.

[0019] A crack prevention pouring method of a complex structure cast steel part, comprising the following steps:

[0020] S1, structure design of the pre-embedded crack prevention rib sand core: according to the structure and material of the cast steel part, and using computer simulation software, the shape structure and size of the crack prevention rib sand core are determined, and the size of the crack prevention rib core box is determined;

[0021] S2, preparation of the pre-embedded crack prevention rib sand core: using resin self-hardening sand as raw material, and selecting a sand box with appropriate size, a crack prevention rib core box mold is manufactured; the surface of the crack prevention rib core box mold is respectively coated, polished and brushed with a release agent, and then special sand is used to seed sand in the crack prevention rib core box mold, and finally the pre-embedded crack prevention rib sand core is obtained by demolding;

[0022] S3, preparation of the cast steel part sand mold: selecting a sand box with appropriate size, placing the cast steel part mold, and placing the pre-embedded crack prevention rib sand core on the position of the cast steel part mold where the crack prevention rib is needed; then using resin self-hardening sand as raw material, filling sand in the sand box to make a mold, and finally demolding after hardening to obtain a cast steel part sand mold with a pre-embedded crack prevention rib sand core;

[0023] S4, pouring the cast steel part: pouring molten steel in the cast steel part sand mold with the pre-embedded crack prevention rib sand core, thereby obtaining a complex structure cast steel part with crack prevention based on the pre-embedded crack prevention rib.

[0024] In the step S3 of preparing the cast steel part sand mold, the pre-prepared crack prevention rib can be placed in the pre-embedded crack prevention rib sand core, and then through the step S4 of pouring the cast steel part, a complex structure cast steel part with crack prevention with the pre-prepared crack prevention rib is obtained; or the pre-prepared crack prevention rib can not be placed in the cast steel part sand mold with the pre-embedded crack prevention rib sand core, and through the step S4 of pouring the cast steel part, a complex structure cast steel part with crack prevention with the crack prevention rib integrated with the cast steel part is directly poured out.

[0025] In the step S2, the influencing factors of the use amount of the special sand of the pre-embedded crack prevention rib sand core include: the original mold number M0 of the cast steel part, the equivalent mold number M1 of the cast steel part after using the special sand, the coefficient n, the thickness of the chilled area cast part, and the strength of the sand core, etc.

[0026] The calculation formula of the use amount of the special sand of the pre-embedded crack prevention rib sand core is:

[0027] A C1 =(A S -A0) / n=(V0 / M1-V0 / M0) / n=V0(M0-M1) / n*M0*M1;

[0028] wherein A C1 is the working surface area of the special sand; A S is the equivalent area of the sand mold; A0 is the surface area of the chilled area of the casting; M0 is the original mold number of the casting, M1 is the equivalent mold number of the casting after using the special sand, M0 and M1 can be calculated manually according to the size, thickness, shape and the like of the casting, or can be calculated by using a special computer simulation software; V0 is the volume of the casting; n is a coefficient, which is determined according to the thickness of the chilled area, and is generally 0.2-1.0.

[0029] The thickness of the pre-embedded anti-crack rib sand core is determined according to the thickness of the chilled area and the strength of the sand core, mainly because the special sand for preparing the anti-crack rib is different from the material of the casting, and is generally 1-5 times the thickness of the chilled area.

[0030] The working surface area A C1 of the special sand of the pre-embedded anti-crack rib sand core is calculated by the calculation formula of the amount of the special sand of the pre-embedded anti-crack rib sand core, and the contact area of the pre-embedded anti-crack rib sand core and the steel casting is combined, and the thickness of the pre-embedded anti-crack rib sand core is combined, so that the amount of the special sand of the pre-embedded anti-crack rib sand core can be calculated.

[0031] The working surface area A C1 of the special sand of the pre-embedded anti-crack rib sand core is calculated by the calculation formula of the amount of the special sand of the pre-embedded anti-crack rib sand core, and the contact area of the pre-embedded anti-crack rib sand core and the steel casting is combined, and the thickness of the pre-embedded anti-crack rib sand core is combined, so that the amount of the special sand of the pre-embedded anti-crack rib sand core can be calculated.

[0032] The anti-crack rib sand core uses special sand to be prepared, and the amount of the special sand can be accurately controlled, so that the chilled area of the anti-crack rib sand core can be accurately controlled, and the product can be accurately controlled. The anti-crack rib sand core can be accurately controlled, and the anti-crack rib sand core can be accurately controlled.

[0033] The above content is only an example and description of the structure of the application, and those skilled in the art can make various modifications or supplements or use similar ways to replace the described specific embodiments, as long as the structure of the application is not deviated or beyond the scope defined by the present application. The scope of the present application.

Claims

1. A method for preventing cracking during casting of complex structural cast steel parts, characterized in that, Includes the following steps: S1. Structural design of pre-embedded anti-crack reinforcement sand core: Based on the structure and material of the cast steel parts, and using computer simulation software, the shape, structure and size of the anti-crack reinforcement sand core are calculated and determined in a comprehensive manner, and the size of the anti-crack reinforcement core box is determined. S2. Preparation of pre-embedded anti-crack reinforcement sand core: Using resin self-hardening sand as raw material and selecting sand boxes of appropriate size, an anti-crack reinforcement core box mold is manufactured; the surface of the anti-crack reinforcement core box mold is coated, polished, and coated with release agent; then special sand is used to plant sand in the anti-crack reinforcement core box mold; finally, the mold is removed to obtain the pre-embedded anti-crack reinforcement sand core. Factors affecting the amount of special sand used in the pre-embedded anti-crack reinforcement sand core include: the original modulus M0 of the cast steel part, the equivalent modulus M1 of the cast steel part after using special sand, the coefficient n, the thickness of the casting in the chilled zone, and the strength of the sand core. The formula for calculating the amount of special sand used in the pre-embedded anti-crack reinforcement sand core is as follows: A C1 = (A S -A0) / n=(V0 / M1-V0 / M0) / n=V0(M0-M1) / n*M0*M1; where A C1 For the working surface area of ​​special sand; A S A0 is the equivalent area of ​​the sand mold; M0 is the surface area of ​​the casting in the chilled zone; M1 is the original modulus of the casting; V0 is the equivalent modulus of the casting after using special sand; n is the volume of the casting; n is a coefficient, which is determined according to the thickness of the casting in the chilled zone and is taken as 0.2-1.

0. The working surface area AC1 of the special sand is calculated by the above formula, which is the contact area between the pre-embedded anti-crack reinforcement sand core and the steel casting. Combined with the thickness of the pre-embedded anti-crack reinforcement sand core, the amount of special sand used in the pre-embedded anti-crack reinforcement sand core can be calculated. The thickness of the pre-embedded anti-crack reinforcement sand core is determined based on the thickness of the casting in the chilled zone and the strength of the sand core, and is taken as 1-5 times the thickness of the casting in the chilled zone. S3. Preparation of sand mold for cast steel parts: Select a sand box of appropriate size, place the cast steel part mold, and place the pre-embedded anti-crack rib sand core on the cast steel part mold at the position where the anti-crack rib needs to be set; then use resin self-hardening sand as raw material, fill the sand box with sand to shape, and finally remove the mold after hardening to obtain a sand mold for cast steel parts with pre-embedded anti-crack rib sand core. S4. Casting steel parts: Molten steel is poured into a sand mold containing pre-embedded anti-crack ribs to produce a complex structure of cast steel parts that can prevent cracking based on pre-embedded anti-crack ribs. Based on the working surface area A of the special sand C1 Then, by combining the thickness of the pre-embedded anti-crack reinforcement sand core and taking into account the locations where cracks are likely to occur in the steel casting, the optimal quantity, shape and structure of the anti-crack reinforcement can be determined. By preparing the sand mold for the steel casting in step S3, a sand mold for the steel casting with a pre-embedded anti-crack rib sand core is obtained. The pre-prepared anti-crack rib is placed in the pre-embedded anti-crack rib sand core. Then, by pouring the steel casting in step S4, a complex structure steel casting with pre-made anti-crack ribs that can prevent cracks is obtained.