阅读说明：本技术 实型铸造球铁拉延模铸件弹顶销过孔缩孔的控制方法 (Control method for through hole shrinkage of spring top pin of full-mold casting ductile iron drawing die casting ) 是由 徐达义 安伟 刘平 左从军 周顺华 于 2020-05-06 设计创作，主要内容包括：本发明的目的是提供一种实型铸造球铁拉延模铸件弹顶销过孔缩孔的控制方法,采用材质为HT300的内冷铁的插入到单边留2-5mm余量球铁拉延模模型弹顶销孔内,增强内部冷却,内冷铁直径小的直杆插入到弹顶销孔内,后期加工处理掉,弹顶销孔的部分使用铬铁矿砂及出气绳,增强此部位的冷却及散热,整个控制方法可以很好对弹顶销过孔缩孔进行控制,并且还提供了铸件的配方,提高铁液的碳当量,处于过共晶成分,并适当控制一下合金元素的成分比例,从而减少铁液的收缩倾向,并且采用侧顶注式浇注系统,铁水从两边法兰引入,确保弹顶销过孔位置铁水温度低于其他位置,可以更好的控制缩孔。(The invention aims to provide a control method of a spring top pin through hole shrinkage hole of a full mold casting ductile iron drawing die casting, which adopts the technical scheme that an internal chill made of HT300 is inserted into a spring top pin hole of a ductile iron drawing die model with a margin of 2-5mm on one side to enhance internal cooling, a straight rod with small diameter of the internal chill is inserted into the spring top pin hole and is processed in the later stage, chromite sand and an air outlet rope are used for the part of the spring top pin hole to enhance cooling and heat dissipation of the part, the whole control method can well control the spring top pin through hole shrinkage hole, a casting formula is also provided, the carbon equivalent of molten iron is improved, the molten iron is in a hypereutectic component, and the component proportion of an alloy element is properly controlled, so that the shrinkage tendency of the molten iron is reduced, and a side top injection type pouring system is adopted, molten iron is introduced from flanges on two sides to ensure that the molten iron temperature at the position of the spring top pin through, the shrinkage cavity can be better controlled.)

1. A control method for a through hole shrinkage of a spring top pin of a drawing die casting of full mold casting ductile iron is characterized by comprising the following steps:

through analysis of the model structure, the spring ejector pin through hole is positioned at the lower part of the mold lightening hole, the chilling effect cannot be achieved by adopting measures such as external chill and chromite sand, the shrinkage hole is positioned at the middle part generally, and the internal cooling is enhanced by adopting an internal chill mode; the structure combination of the internal chill: in order to enhance the cooling effect of the hole and avoid the phenomenon of hole shrinkage, the chilling block is made into a shape that two straight rods are connected together, wherein the diameter of one straight rod is smaller than that of the other straight rod, the material is HT300, and the post-processing is easy when the hardness is low;

making a single side of a bullet top pin hole of the ductile iron drawing die and reserving 2-5mm of allowance;

combining the internal chill with the spring top pin hole of the ductile iron drawing die model, inserting the straight rod with small diameter of the internal chill into the spring top pin hole, and performing post processing;

chromite sand and an air outlet rope are used for the part of the bullet top pin hole of the ductile iron drawing die model, so that the cooling and heat dissipation of the part are enhanced.

2. The method for controlling the pin piercing shrinkage of the full mold casting ductile iron drawing die casting bullet top pin according to claim 1, wherein the method comprises the following steps: the formula of the ductile iron drawing die model casting is as follows: 3.6 to 3.8 percent of C, 2.3 to 2.5 percent of Si, 0.45 to 0.55 percent of Mn, less than or equal to 0.12 percent of Cr, 0.4 to 0.5 percent of Mo, 0.85 to 0.9 percent of Cu, 0.9 to 1.0 percent of Ni, 0.04 to 0.06 percent of Mg, 0.02 to 0.04 percent of Re, less than or equal to 0.05 percent of P, less than or equal to 0.012 percent of S, and the balance of Fe and inevitable impurity elements; the carbon equivalent of the molten iron is increased to be in a hypereutectic composition, and the composition proportion of the alloy elements is properly controlled, so that the shrinkage tendency of the molten iron is reduced.

3. The method for controlling the pin piercing shrinkage of the full mold casting ductile iron drawing die casting bullet top pin according to claim 1, wherein the method comprises the following steps: the full-mold casting ductile iron drawing die casting adopts a side-top pouring type pouring system, molten iron is introduced from flanges on two sides, and the temperature of the molten iron at the position of a through hole of an elastic ejection pin is lower than that of molten iron at other positions.

4. The method for controlling the pin piercing shrinkage of the full mold casting ductile iron drawing die casting bullet top pin according to claim 1, wherein the method comprises the following steps: the internal chill needs to be machined and formed, the surface needs to be smooth and rustless, the end part is machined to be 20mm in diameter and 100mm in length, and chilling and heat dissipation are increased.

5. The method for controlling the pin piercing shrinkage of the full mold casting ductile iron drawing die casting bullet top pin according to claim 1, wherein the method comprises the following steps: the bullet top pin hole of the ductile iron drawing die model is made into a hole with 2 quantity left on one side.

6. The method for controlling the pin piercing shrinkage of the full mold casting ductile iron drawing die casting bullet top pin according to claim 1, wherein the method comprises the following steps: the diameter and the length of the straight rod with the small diameter of the inner chill are the same as the diameter and the depth of the spring ejection pin hole.

Technical Field

The invention relates to the field of full mold casting, in particular to a control method for a through hole shrinkage of a spring top pin of a full mold casting ductile iron drawing die casting.

Background

The bottom surfaces of most ductile iron drawing die castings in an automobile stamping die are provided with elastic ejection pin holes, the elastic ejection pins are used for fixing the elastic ejection pins (the elastic ejection pins separate stamping plates from the stamping die), the elastic ejection pins are required to be installed at the positions, the structural design is thicker than other positions, and the hole shrinkage defect is caused in the machining process after the casting due to the fact that the wall thickness is uneven and the bottom surface is difficult to dissipate heat at the hole portions. The structure is arranged at a deep cavity of the bottom surface, is thick and isolated, cannot be fed by a riser, and has an unobvious chilling effect on the conventional external chill, so that the actual production is difficult.

Disclosure of Invention

In order to solve the problems, the invention provides a control method of a spring top pin through hole shrinkage hole of a full-mold casting ductile iron drawing die casting, which adopts an internal chill made of HT300 to be inserted into a spring top pin hole of a ductile iron drawing die model with 2-5mm allowance left on one side to enhance internal cooling, a straight rod with small diameter of the internal chill is inserted into the spring top pin hole and is processed in the later stage, chromite sand and an air outlet rope are used for the part of the spring top pin hole to enhance the cooling and heat dissipation of the part, the whole control method can well control the spring top pin through hole shrinkage hole, and also provides a casting formula, improves the carbon equivalent of molten iron, is in hypereutectic composition, properly controls the composition proportion of alloy elements, thereby reducing the shrinkage tendency of the molten iron, adopts a side top injection type pouring system, leads the molten iron from flanges on two sides, ensures that the temperature of the molten iron at the position of the spring top pin through hole is lower than that of other positions, the shrinkage cavity can be better controlled, and the problems in the background technology are solved.

The invention aims to provide a control method for a spring top pin through hole shrinkage of a drawing die casting of full-mold casting ductile iron,

through analysis of the model structure, the spring ejector pin through hole is positioned at the lower part of the mold lightening hole, the chilling effect cannot be achieved by adopting measures such as external chill and chromite sand, the shrinkage hole is positioned at the middle part generally, and the internal cooling is enhanced by adopting an internal chill mode; the structure combination of the internal chill: in order to enhance the cooling effect of the hole and avoid the phenomenon of hole shrinkage, the chilling block is made into a shape that two straight rods are connected together, wherein the diameter of one straight rod is smaller than that of the other straight rod, the material is HT300, and the post-processing is easy when the hardness is low;

making a single side of a bullet top pin hole of the ductile iron drawing die and reserving 2-5mm of allowance;

combining the internal chill with the spring top pin hole of the ductile iron drawing die model, inserting the straight rod with small diameter of the internal chill into the spring top pin hole, and performing post processing;

chromite sand and an air outlet rope are used for the part of the bullet top pin hole of the ductile iron drawing die model, so that the cooling and heat dissipation of the part are enhanced.

The further improvement lies in that: the formula of the ductile iron drawing die model casting is as follows: 3.6 to 3.8 percent of C, 2.3 to 2.5 percent of Si, 0.45 to 0.55 percent of Mn0.45, less than or equal to 0.12 percent of Cr, 0.4 to 0.5 percent of Mo, 0.85 to 0.9 percent of Cu, 0.9 to 1.0 percent of Ni, 0.04 to 0.06 percent of Mg, 0.02 to 0.04 percent of Re0.05 percent, less than or equal to 0.05 percent of P, less than or equal to 0.012 percent of S, and the balance of Fe and inevitable impurity elements. The carbon equivalent of the molten iron is increased to be in a hypereutectic composition, and the composition proportion of the alloy elements is properly controlled, so that the shrinkage tendency of the molten iron is reduced.

The further improvement lies in that: the full-mold casting ductile iron drawing die casting adopts a side-top pouring type pouring system, molten iron is introduced from flanges on two sides, and the temperature of the molten iron at the position of a through hole of an elastic ejection pin is lower than that of molten iron at other positions.

The further improvement lies in that: the internal chill needs to be machined and formed, the surface needs to be smooth and rustless, the end part is machined to be 20mm in diameter and 100mm in length, and chilling and heat dissipation are increased.

The further improvement lies in that: the bullet top pin hole of the ductile iron drawing die model is made into a hole with 2 quantity left on one side.

The further improvement lies in that: the diameter and the length of the straight rod with the small diameter of the inner chill are the same as the diameter and the depth of the spring ejection pin hole.

The invention has the beneficial effects that: the method adopts the technical scheme that an inner chill made of HT300 is inserted into a bullet top pin hole of a ductile iron drawing die model with a 2-5mm allowance on one side, the internal cooling is enhanced, a straight rod with a small diameter of the inner chill is inserted into the bullet top pin hole and is processed in a later stage, chromite sand and an air outlet rope are used for the part of the bullet top pin hole, the cooling and the heat dissipation of the part are enhanced, the whole control method can well control the bullet top pin through the hole shrinkage, the formula of a casting is also provided, the carbon equivalent of molten iron is improved, the molten iron is in an over eutectic composition, and the composition proportion of an alloy element is properly controlled, so that the shrinkage tendency of the molten iron is reduced, and a side top injection type pouring system is adopted, the molten iron is introduced from flanges on two sides, the temperature of the molten iron at the position of the bullet top pin through hole is lower.

Drawings

Fig. 1 is a schematic view of the chill of the present invention.

FIG. 2 is a schematic representation of a ductile iron drawing die mold of the present invention.

FIG. 3 is a schematic illustration of a bullet pin hole of the ductile iron drawing die mold of the present invention.

FIG. 4 is a schematic view of the combination of the spring top pin hole and the internal chill of the ductile iron drawing die of the present invention.

Detailed Description

For the purpose of enhancing understanding of the present invention, the present invention will be further described in detail with reference to the following examples, which are provided for illustration only and are not to be construed as limiting the scope of the present invention.

As shown in fig. 1-4, the present embodiment provides a method for controlling pin piercing and necking in drawing die casting of full mold casting ductile iron,

through analysis of the model structure, the spring ejector pin through hole is positioned at the lower part of the mold lightening hole, the chilling effect cannot be achieved by adopting measures such as external chill and chromite sand, the shrinkage hole is positioned at the middle part generally, and the internal cooling is enhanced by adopting an internal chill mode; the structure combination of the internal chill: in order to enhance the cooling effect of the hole and avoid the phenomenon of hole shrinkage, the chilling block is made into a shape that two straight rods are connected together, wherein the diameter of one straight rod is smaller than that of the other straight rod, the material is HT300, and the post-processing is easy when the hardness is low;

making a single side of a bullet top pin hole of the ductile iron drawing die and reserving 3mm allowance;

combining the internal chill with the spring top pin hole of the ductile iron drawing die model, inserting the straight rod with small diameter of the internal chill into the spring top pin hole, and performing post processing;

chromite sand and an air outlet rope are used for the part of the bullet top pin hole of the ductile iron drawing die model, so that the cooling and heat dissipation of the part are enhanced.

The formula of the ductile iron drawing die model casting is as follows: 3.7 percent of C, 2.4 percent of Si, 0.50 percent of Mn, less than or equal to 0.12 percent of Cr, 0.5 percent of Mo, 0.87 percent of Cu, 1.0 percent of Ni, 0.05 percent of Mg, 0.03 percent of Re, 0.05 percent of P, 0.012 percent of S, and the balance of Fe and inevitable impurity elements. The carbon equivalent of the molten iron is increased to be in a hypereutectic composition, and the composition proportion of the alloy elements is properly controlled, so that the shrinkage tendency of the molten iron is reduced.

The full-mold casting ductile iron drawing die casting adopts a side-top pouring type pouring system, molten iron is introduced from flanges on two sides, and the temperature of the molten iron at the position of a through hole of an elastic ejection pin is lower than that of molten iron at other positions.

The internal chill needs to be machined and formed, the surface needs to be smooth and rustless, the end part is machined to be 20mm in diameter and 100mm in length, and chilling and heat dissipation are increased. The bullet top pin hole of the ductile iron drawing die model is made into a hole with 2 quantity left on one side.

The diameter and the length of the straight rod with the small diameter of the inner chill are the same as the diameter and the depth of the spring ejection pin hole.

The method is characterized in that internal chill made of HT300 is inserted into a spring top pin hole of a ductile iron drawing die model with 3mm allowance left on one side, internal cooling is enhanced, a straight rod with a small diameter of the internal chill is inserted into the spring top pin hole and is processed in a later stage, chromite sand and an air outlet rope are used for the spring top pin hole, cooling and heat dissipation of the spring top pin hole are enhanced, the whole control method can well control the spring top pin hole shrinkage, a casting formula is further provided, carbon equivalent of molten iron is improved, hypereutectic components are included, and the component proportion of a next alloy element is properly controlled, so that the shrinkage tendency of the molten iron is reduced.