Pouring machine common problems summary

First, the common problems of pouring machine

1, do not know what is the best pouring? This leads to the wrong evaluation and selection of pouring equipment.

2, the use of vertical parting box-free modeling line, but mistakenly choose to supplement the hot metal needs to stop production or low efficiency pouring machine.

3, the use of vertical parting molding line, but the wrong choice of horizontal parting molding line pouring machine.

4, non-heated casting machine for horizontal parting box molding line casting gray iron, which is definitely not an ideal choice, especially for the production of large complex parts (such as engine body and cylinder head castings), which is simply a mistake.

5, mistakenly believe that the horizontal molding line casting machine must have the function of chasing bags in order to normal production.

6, in the high-speed molding line, mistakenly think that manual casting than automatic casting machine saving.

7, ductile iron production, the wrong choice of non-ductile iron casting machine.

8, there are a lot of overpouring and underpouring, and sometimes overpouring even leads to modeling line damage.

9. Confuse the difference between mechanized pouring machine, predictive semi-automatic pouring machine and automatic pouring machine.

10. Spray occurs during pouring, and a large amount of hot metal splashes.

11. There are more waste products in slag holes and pores, and serious sand washing.

12, the casting yield is low.

13, the inoculation effect is not good, the casting quality is not high.

14, the casting machine temperature loss is too large, the temperature drop is very large, often reaching 5 ~ 8℃/min.

15, casting machine lining life is too low.

16, casting machine oxidation slag too much, difficult to remove.

Two, what is the best pouring, you poured the right?

Before going into the pouring machine, it is necessary to first discuss what is the best pouring machine? Many people believe that the best pouring is to accurately pour hot metal into the mold within the specified time. Some people also believe that the best pouring must be perfect, completely free of pouring defects and waste pouring. In fact, these two views are not quite correct, we believe that the best pouring refers to the person or pouring equipment accurately pour hot metal into the pouring cup, and always keep the pouring cup liquid level full during the pouring process until the end of the pouring process.

This is because we believe that keeping the pouring cup full is the best that can be achieved. If the pouring system is poorly designed, the hot metal cannot flow into the mold in time, resulting in the failure to complete the pouring at the specified time; If the pouring system design is too large, resulting in hot metal can not fill the pouring cup, resulting in oxidation slag, molding sand, gas directly into the mold, resulting in sand washing, slag inclusion, porosity defects; If the gating system design problems or mold sand permeability is not good, resulting in sputtering, etc.; It has nothing to do with pouring.

Third, taking the horizontal parting box molding line as an example, explain how to choose the pouring machine

Horizontal parting box molding line is generally divided into domestic simple mechanized molding line or imported automatic molding line. The biggest feature of domestic simple mechanized modeling line is that the general modeling speed is slow, dozens of types per hour, and the sand box size is not too large. This molding line generally uses manual pouring or mechanized pouring machines (such as teapot ladling machines or fan pouring machines) to meet the needs, and we will not discuss it here. The biggest feature of the imported automatic molding line or some domestic pneumatic stroke line is that the molding line speed is higher, the mechanism is extremely complex, the auxiliary machine is more, the core task is often heavy, and the molding line is often stopped for a short time for various reasons. This situation is more complicated, below we will briefly analyze according to different situations:

For the horizontal parting box molding line, some engineers believe that the bottom pouring machine cannot be used, and the large teapot pouring machine must be used. For example, a famous domestic diesel engine factory produces a large number of single gray iron castings produced by the engine body and cylinder head, and they spend nearly 10 million to introduce a large teapot pouring machine for pouring. But in fact, in other countries in the world, this is the most suitable application of the standard air insulation casting furnace. As we all know, this large modeling line is often composed of many hosts and auxiliary machines, and often has a heavy core task, often discontinued for various reasons. The use of non-heating casting machine, even if we temporarily do not consider the impact of the reliability of the casting machine, only the temperature loss of molten iron in the casting machine is very large, once the molding line is stopped for a short time due to various reasons, often lead to the casting machine because the temperature of molten iron in the bag is too low and can not be poured, it must be returned to the electric furnace to heat up, which not only affects the casting machine and molding line productivity, It also affects the normal production of electric furnace. And once the molding line returns to production, the casting machine may also need to be ironed and preheated before it can be used, greatly affecting productivity.

Therefore, for the production of gray iron with horizontal parting box molding line, it is most suitable to use heating insulation casting furnace, and some foreign foundries, even after using insulation casting furnace, directly cancel the insulation furnace, and change the production process to the melting road - insulation casting furnace double process, which greatly reduces the operating cost and improves the production efficiency of the molding line.

For the horizontal parting box molding line production of ductile iron situation is different, because the ductile iron oxidation slag is particularly large, it is very difficult to remove in the heat preservation casting furnace, even if the use of nitrogen protection and other measures, there will still be a lot of oxidizing slag, often affect the use of casting furnace. In this case, we instead recommend the use of appropriate size of non-heating insulation ladle. This is because ductile iron due to the decline of spheroidization, the general requirement of 8 to 10 minutes must be added to the hot metal, if can not be added to the hot metal, it must be returned to the furnace. Therefore, the defects of the unheated ladle are not so obvious here. However, in the foundry in Europe and the United States, if the production of complex ductile iron parts, it is still often used with heating and insulation casting furnace. This is because they believe that the heating furnace can maintain a constant temperature and can keep the hot metal pure, which is crucial to the production of high-quality castings, even if the heavy slag cleaning labor is worth it.

Four, coreless pressure casting furnace and core pressure casting furnace comparison

At present, the casting furnace with heating and insulation is divided into core casting furnace and coreless casting furnace. The common characteristics of the heat preservation casting furnace are: constant temperature, which can accurately control the pouring temperature, which is very conducive to the improvement of casting quality; Secondly, due to the pneumatic and siphon principle, most of the oxidizing slag in the hot metal floats on the surface of the hot metal before pouring, so the hot metal is relatively pure and the quality of the hot metal is better; There is often a large capacity of the thermal insulation casting furnace, a huge buffer for the production process, and even often can replace the thermal insulation furnace. And due to the use of nitrogen protection, spheroidization decay time is longer.

The main advantages of the core casting furnace are: energy saving, good insulation effect, long lining life, sometimes more than two years, large capacity, strong buffer capacity, if the use of nitrogen protection, you can extend the nodulization decline time and so on. The disadvantage is that the power supply must be 24 hours, and the power cannot be cut off, so it is often required to be equipped with an emergency generator, and the hot metal can not be emptied during production, and it is difficult to replace the hot metal grade.

In view of the shortcomings of coreless casting furnaces, coreless casting furnaces have been developed in recent years. In addition to the general advantages of thermal insulation pouring furnace, coreless pouring furnace can also be powered off, can empty the hot metal, and can easily replace the hot metal grade, completely overcoming the main shortcomings of the core pouring furnace, which seems to be very ideal. However, it also brings new disadvantages: more residual hot metal is needed, the production of ductile iron requires spheroidizing treatment, and the lining life is much shorter than that of the core casting furnace, and the energy consumption is relatively high.