Sunrise Foundry CO.,LTD |
Grey Iron Sand Casting Bracket for Truck Parts
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Production Process
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Quality Control
FAQ
1. How to prevent the formation of air holes in castings?
The effective methods to prevent bubbles are: reducing the gas
content in the metal liquid, increasing the air permeability of
sand mold, and adding an air riser at the top of the mold cavity.
2. How to avoid the situation of sticky sand?
The surface of the casting is adhered to a layer of sand which is
difficult to remove.It not only affects the appearance of
casting, but also increases the workload of casting cleaning and
cutting, and even affects the life of the machine.The method to
prevent the formation of sand is to add coal powder in molding
sand, and to brush the surface of the cast mold with anti-sand
paint.
3. How to identify shrinkage?
(1) Observe the surface shape of casting defects. If the surface is
uneven, very rough, and dark gray, the hole with irregular
shape is shrinkage cavity.
(2) If the location of the hole is at the final solidification
thickening of the casting, or at the hot spot where the two walls
intersect, and is located in the middle or upper part of the
section, it is a shrinkage cavity.
(3) The most concentrated hole defects on the thick and large
section of steel castings are shrinkage or air shrinkage.
4. How to prevent sand expansion?
In order to prevent sand expansion, the strength of sand mold and
the rigidity of sand box should be increased, and the pressing
force or fastening force when closing the box should be increased.
In addition, the pouring temperature should be reduced to make the
surface of molten metal crust earlier, so as to reduce the pressure
of molten metal on the mold.
5. How to prevent sand inclusion?
Sand inclusion is a kind of groove and scar defect formed on the
surface of castings, which is very easy to produce in wet mold
casting of heavy plate castings. Avoiding large plane structure can
effectively prevent sand inclusion.
6. How to identify the wrong type, wrong core and off-core?
(1) Dislocation is the defect that one part of the casting is
staggered with another part at the parting surface, which is
usually caused by inaccurate positioning of the mold.
(2) The core staggering is that the sand cores are staggered at the
parting surface, which makes the inner cavity of the casting deform
and the outer surface shape of the casting is correct.
(3) Core deviation is caused by improper change of sand core
position, which results in casting shape and size inconsistent with
the drawing.