In order to ensure the compactness of the casting structure, in addition to the necessary feeder replenishment, the debris in the casting mold must be effectively removed, so a clutter is provided at the bottom of the casting mold to ensure the purity of the molten steel. In actual production, in addition to the above purpose, the craft ribs can also achieve functions such as shrinkage and slag discharge, thereby improving the quality of castings. It does not have to be removed. 1, using FeSiMg6RE2 low magnesium spheroidizing agent for capping spheroidizing treatment At this time, the spheroidization reaction time is stable at about 68s. The common method of solution is to use the feeder shrinkage method, the cold iron method, the casting plus subsidy method, etc. Two slag-discharging process ribs are installed. It is also necessary to add process ribs on specific casting structures to achieve: increase the rigidity and strength of castings and prevent casting deformation; reduce The wall thickness of small castings can prevent shrinkage holes and cracks in castings; reduce large planes to prevent sand inclusions and scars on castings. 1. The presence of reinforcing ribs can increase the rigidity and strength of the parts without increasing the wall thickness of the parts, thereby reducing weight, saving materials, and reducing costs. The casting material is about 34kg. 2 Design of special casting process ribs 2. In order to solve the deformation of the ribs caused by insufficient rigidity, the thickness of the ribs will be increased to 8mm, and trial production will be carried out, then the problem of rib deformation will be solved. When the stress exceeds the yield limit of the material, warping deformation is easy to occur. In response to this problem, if a process flange is added on the lower slab to increase its thickness, the lower slab and the connecting ribs should be cured as much as possible to avoid the generation of thermal stress.1 Design of slag discharge casting process ribs is a simple drawing of stainless steel valve body casting process., but it is obviously not suitable for this casting. The cooling conditions of the upper and lower surfaces are not the same. If the process rib (reinforcement rib) is added, the large plane is divided into several small planes, which can effectively avoid the above problems. Through the research on the role of process ribs in casting production, this paper analyzes and studies the design of special casting process ribs for typical castings, which has a multiplier effect in preventing casting defects and improving the quality of castings. . The upper, middle, and lower three-layer plates are connected by 8 rib plates with a width of 6mm, and Eight ribs with a width of 6 mm are evenly distributed between the middle and lower two layers of boards.1 Process ribs to adjust the cooling rate of castings For flat castings with thinner wall thickness and larger plane, although the solidification method is mainly simultaneous solidification, the castings inevitably make large The plane faces up and down. After spheroidization, the graphite spheres are rounder and finer, and the spheroidization rate is high. The casting after the process ribs are installed effectively solves the scum phenomenon and ensures the quality of the casting. 2. Therefore, when designing parts, the wall thickness should be as uniform as possible to prevent the above defects. stress. As we all know, in casting production, because there are many factors that affect the quality of castings, it is not enough to consider reinforcement ribs.Reinforcing ribs are an indispensable consideration when designing parts, especially thin-walled parts. When the casting wall is thick, the spheroidizing temperature can be slightly lower, and when the casting wall is thin, the spheroidizing temperature can be slightly higher. The casting weight is about 60kg, and the main wall thickness is about 8mm. However, for actual production, when the spheroidizing agent is selected, the proper spheroidizing temperature should be selected according to the different wall thickness of the casting. Considering that the body shrinkage of stainless steel is relatively large, although the wall thickness of the casting is not large, there must be better shrinkage measures to avoid shrinkage or shrinkage. In addition, this structure can also effectively improve the rigidity of castings, so the process bronze gear Manufacturers https://www.bronzecast.net/product/transmission-parts-series/worm-wheels-gears-cogs/ ribs can also be called reinforcement ribs. The technological ribs can be removed by machining during machining. It can be seen from Table 2 that the residual magnesium content in the molten iron is higher after spheroidization, the absorption rate of magnesium is higher and the fluctuation is smaller, and it is not greatly affected by temperature.
The riser must be considered when formulating the casting process. To this end, design a waist riser on the top. Although it can be used after welding, it is obvious Casting defects. 1 Introduction to the design of conventional process ribs 1. spheroidizing treatment Temperature plant c plus residual magnesium absorption rate table 3 Graphite size and spheroidization rate at different spheroidizing temperatures Tab. The analysis believes that the reason for the occurrence of scum is that the molten steel slag at the flange A cannot effectively float into the riser, and this problem can be solved if a slag discharge channel is provided. It can be seen from Table 3 that the higher residual magnesium content obtains a good graphite spheroidization effect. Of course, in the case of ensuring the performance of flat parts, when designing the structure of the parts, you can add reinforcement ribs on one side to improve the strength and rigidity of the parts, and at the same time play the role of casting process ribs, and the reinforcement ribs are used during machining.. For this reason, the casting adopts the casting process of horizontal casting. The heat dissipation conditions on the upper surface are better than those of the following process theory and application; the surface is better and the cooling speed is faster, resulting in the upper and lower surfaces not solidifying at the same time, resulting in different shrinkage stresses. 1.3 The design of the shrinking process rib is a sketch of the casting process of the precision casting of the spring cover. If you add several process ribs on the lower surface during design to make the process ribs and the upper surface cool at the same rate (note: the wall thickness of the process ribs should ensure that the casting is solidified at the same time), you can avoid the occurrence of deformation of the casting. During solidification and shrinkage, defects such as shrinkage and shrinkage are likely to form at the hot joints. Magnesium absorption rate number under different spheroidizing temperature No. According to the analysis, the main reason for the deformation is the insufficient rigidity of the connecting rib. After adding the process flange (thickness 3mm), the local thickness of the lower slab reaches 9mm, which is basically the same as the thickness of the connecting rib, so as to achieve the purpose of simultaneous solidification of the connecting rib and the lower slab, which also solves the casting defect of the crack at A.
However, new problems were discovered during production, and eight thermal cracks appeared at the middle A (where the middle and lower two-layer plates are connected to the ribs). 3 Conclusion When the low magnesium spheroidizing agent is covered by the spheroidizing process, the spheroidizing temperature is adjusted between 14501500C. It can be seen from Table 4 that a good spheroidizing effect ensures high and stable mechanical properties of nodular iron after spheroidizing. However, after the casting was cleaned, a small amount of scum was found at A (the flange height of about 5 on both sides), which seriously affected the quality of the casting. 2. In addition, the cooling rate of each part is different, and it is easy to form thermal stress, which causes cracks at the connection between the thin and thick walls of the casting.2 Process for preventing shrinkage and cracking of castings The wall thickness of each part of the rib casting is too large, which will cause local accumulation of metal to form hot joints. The analysis shows that after the connecting rib plate is increased to 8mm, the thickness is different from the lower plate (6mm), and the connecting rib plate is inside the casting, and the cooling rate is lower than the lower rib plate. Strictly speaking, this reinforcing rib can also be called a process rib, mainly to prevent the wall thickness from being too large and causing defects such as shrinkage and shrinkage. Especially after the carburizing and quenching heat treatment, the deformation of the connecting ribs will increase and lead to the casting scrap. During the casting process, it was found that the 6mm connecting ribs on the upper, middle and lower layers of the casting were slightly deformed. After the spheroidizing process, the magnesium absorption rate is high and stable, the graphite spheres are rounder and finer, and the spheroidization rate High, high mechanical properties of ductile iron. The tensile test and tensile elongation of the sample are shown in Table 4.2 The design of the anti-cracking casting process ribs (blocks) is the original brake rotor precision casting, weighing about 43kg, and the material is 20CrMnMo. 4 Nodular iron mechanical properties at different spheroidizing temperature No. For this reason, to reduce the wall thickness, but can not reduce its strength, the use of reinforcing ribs is a very effective means. Table 2. When the tensile stress is greater than its high temperature strength, thermal cracking occurs (there are cracks at all 8 joints, and the crack fracture form has been determined to be thermal cracking). Because it is used in a highly corrosive medium environment, the valve body is made of 1Cr18Ni9Ti.3 Process ribs to prevent sand inclusion and scarring of castings When the plane of the casting is large, if certain technical measures are not taken, the strong radiation of molten metal on the upper surface of the cavity during the pouring process may easily make the upper surface sand sharp The ground expands and arches or cracks, causing sand inclusions and scarring defects on the surface of the casting. In use, the casting is required to withstand a pressure of 2. There is a round table (quasi-120mmx20mm) and cylinder (quasi-44mmx170mm) in the middle. However, there are 4 local hot joints (N in the figure) on the bottom flange (thickness 26mm). After discussing with the relevant designers, the two slag removal process ribs do not need to be removed during mechanical processing. Because the top riser cannot be compensated, shrinkage occurs during drilling of the casting.5 MPa or less without leakage, so the compactness of the cast structure must be considered when formulating the casting process. There was no premature initiation in the test, no spheroidizer agglomeration at the bottom of the bag, nodularization reaction was stable, and production was stable. The wall thickness of the cylindrical structure part is 10mm. spheroidizing temperature Plant C tensile strength/MPa elongation can be seen from sample No
The riser must be considered when formulating the casting process. To this end, design a waist riser on the top. Although it can be used after welding, it is obvious Casting defects. 1 Introduction to the design of conventional process ribs 1. spheroidizing treatment Temperature plant c plus residual magnesium absorption rate table 3 Graphite size and spheroidization rate at different spheroidizing temperatures Tab. The analysis believes that the reason for the occurrence of scum is that the molten steel slag at the flange A cannot effectively float into the riser, and this problem can be solved if a slag discharge channel is provided. It can be seen from Table 3 that the higher residual magnesium content obtains a good graphite spheroidization effect. Of course, in the case of ensuring the performance of flat parts, when designing the structure of the parts, you can add reinforcement ribs on one side to improve the strength and rigidity of the parts, and at the same time play the role of casting process ribs, and the reinforcement ribs are used during machining.. For this reason, the casting adopts the casting process of horizontal casting. The heat dissipation conditions on the upper surface are better than those of the following process theory and application; the surface is better and the cooling speed is faster, resulting in the upper and lower surfaces not solidifying at the same time, resulting in different shrinkage stresses. 1.3 The design of the shrinking process rib is a sketch of the casting process of the precision casting of the spring cover. If you add several process ribs on the lower surface during design to make the process ribs and the upper surface cool at the same rate (note: the wall thickness of the process ribs should ensure that the casting is solidified at the same time), you can avoid the occurrence of deformation of the casting. During solidification and shrinkage, defects such as shrinkage and shrinkage are likely to form at the hot joints. Magnesium absorption rate number under different spheroidizing temperature No. According to the analysis, the main reason for the deformation is the insufficient rigidity of the connecting rib. After adding the process flange (thickness 3mm), the local thickness of the lower slab reaches 9mm, which is basically the same as the thickness of the connecting rib, so as to achieve the purpose of simultaneous solidification of the connecting rib and the lower slab, which also solves the casting defect of the crack at A.
However, new problems were discovered during production, and eight thermal cracks appeared at the middle A (where the middle and lower two-layer plates are connected to the ribs). 3 Conclusion When the low magnesium spheroidizing agent is covered by the spheroidizing process, the spheroidizing temperature is adjusted between 14501500C. It can be seen from Table 4 that a good spheroidizing effect ensures high and stable mechanical properties of nodular iron after spheroidizing. However, after the casting was cleaned, a small amount of scum was found at A (the flange height of about 5 on both sides), which seriously affected the quality of the casting. 2. In addition, the cooling rate of each part is different, and it is easy to form thermal stress, which causes cracks at the connection between the thin and thick walls of the casting.2 Process for preventing shrinkage and cracking of castings The wall thickness of each part of the rib casting is too large, which will cause local accumulation of metal to form hot joints. The analysis shows that after the connecting rib plate is increased to 8mm, the thickness is different from the lower plate (6mm), and the connecting rib plate is inside the casting, and the cooling rate is lower than the lower rib plate. Strictly speaking, this reinforcing rib can also be called a process rib, mainly to prevent the wall thickness from being too large and causing defects such as shrinkage and shrinkage. Especially after the carburizing and quenching heat treatment, the deformation of the connecting ribs will increase and lead to the casting scrap. During the casting process, it was found that the 6mm connecting ribs on the upper, middle and lower layers of the casting were slightly deformed. After the spheroidizing process, the magnesium absorption rate is high and stable, the graphite spheres are rounder and finer, and the spheroidization rate High, high mechanical properties of ductile iron. The tensile test and tensile elongation of the sample are shown in Table 4.2 The design of the anti-cracking casting process ribs (blocks) is the original brake rotor precision casting, weighing about 43kg, and the material is 20CrMnMo. 4 Nodular iron mechanical properties at different spheroidizing temperature No. For this reason, to reduce the wall thickness, but can not reduce its strength, the use of reinforcing ribs is a very effective means. Table 2. When the tensile stress is greater than its high temperature strength, thermal cracking occurs (there are cracks at all 8 joints, and the crack fracture form has been determined to be thermal cracking). Because it is used in a highly corrosive medium environment, the valve body is made of 1Cr18Ni9Ti.3 Process ribs to prevent sand inclusion and scarring of castings When the plane of the casting is large, if certain technical measures are not taken, the strong radiation of molten metal on the upper surface of the cavity during the pouring process may easily make the upper surface sand sharp The ground expands and arches or cracks, causing sand inclusions and scarring defects on the surface of the casting. In use, the casting is required to withstand a pressure of 2. There is a round table (quasi-120mmx20mm) and cylinder (quasi-44mmx170mm) in the middle. However, there are 4 local hot joints (N in the figure) on the bottom flange (thickness 26mm). After discussing with the relevant designers, the two slag removal process ribs do not need to be removed during mechanical processing. Because the top riser cannot be compensated, shrinkage occurs during drilling of the casting.5 MPa or less without leakage, so the compactness of the cast structure must be considered when formulating the casting process. There was no premature initiation in the test, no spheroidizer agglomeration at the bottom of the bag, nodularization reaction was stable, and production was stable. The wall thickness of the cylindrical structure part is 10mm. spheroidizing temperature Plant C tensile strength/MPa elongation can be seen from sample No
