Air hole

Description

A void caused by air or gas entrapped in the die-cast product. Air. The gas is closed under high pressure in the die casting.

It shows a spherical shape and its inner wall is smooth.

the reason

* Through high speed, the dissolved soup is shot into the mold cavity, and the air injected into the material tank or in the mold cannot be discharged outside the cavity, causing it to be wound into the die casting.

* The oil component of the punch lubricant or the release agent is gasified after being contacted with the high-temperature dissolved soup, and is drawn into the die-casting material to cause pores.

* When the mold temperature is low or when the air blow is insufficient, the external cooling water remains on the mold, and after being gasified, it is caught in the die-cast material, and pores are generated.

Countermeasures

*Change of the casting plan (the size of the vent. The size of the exhaust. The position is appropriate)

*Change of casting conditions (casting pressure, filling time, injection speed, mold temperature, high-speed switching time)

*Release agent. Type of punch lubricant. Quantity change

* Appropriate shape of die casting

* Thoroughly blow, abolish the outside cold.

Edge shrinkage

Description

The corner of the product, the crater caused by the solidification and contraction of the R part.

the reason

At the corner of the product, the mold of the R part is partially overheated, and a hot spot is generated. This part becomes the final solidified part, and when the supply of the soup is insufficient, shrinkage occurs.

Countermeasures

* The mold temperature is optimized by the cooling enhancement of the overheated portion.

*Change in product shape (product wall thickness, R part, corner part)

* Improve the replenishment of the soup by changing the casting conditions (solution temperature, injection speed, casting pressure).

* Appropriate casting scheme.

Shrinkage hole of the core surface

Description

A crater in the product part of the front end of the cast pin or core part.

the reason

Casting the pin, the front end of the neutron is overheated, and a hot spot is generated. This part of the solidification is slower and becomes the final solidified part. When the supply of the dissolved soup is poor, shrinkage or shrinkage occurs.

Countermeasures

* Strengthened by cooling, casting pin and pin. The temperature of the neutron part is appropriate.

*Change in product shape (casting hole depth neutron shape, etc.)

*Change of casting conditions (solution temperature, injection speed, injection pressure, etc.)

* Appropriate casting scheme.

Shrinkage

Description

A relatively large void that occurs inside the wall thickness portion or the sharply thickened portion of the product. The shrinkage hole has an irregular shape, and a circle having dendrites on the inner wall surface can be seen.

the reason

During the solidification process of the filling cavity, the solution of the dissolution of the soup at the beginning of the soup is cut off due to solidification, so that the dissolution of the coagulation and shrinkage portion is not timely replenished, and voids occur.

Countermeasures

*Change of casting plan (thickness of width, width, and position of the soup)

*Change of casting conditions (increased speed of soup, shortening of filling time, increase of casting pressure)

* Directivity solidification by mold temperature adjustment.

*Change of the shape of the product (the vertical hole core pin of the shrinkage hole occurs, or the meat is mined, and the thickness of the meat is uniform)

* Localized pressure setting.

Loose hole

Description

A spongy or porous micropore that occurs in the thick portion of the die-cast product or a sharp change in the thickness of the meat.

the reason

Due to solidification and contraction

At the end of solidification, the flow of the liquid phase becomes difficult due to the dendrite gap, and the replenishment of the solidification and shrinkage portion cannot be performed, and is dispersed in a part of the range to cause voids. It is easy to occur when it is in a porridge-solidified form.

2. Caused by hydrogen gas or oxide, or medium

The hydrogen gas dissolved in the dissolved soup is released during solidification, and when fine pores are generated, or the oxide in the dissolved soup is absorbed, the gas on the medium is released. In short, the cleanliness of the dissolved soup occurs when it is not good.

Countermeasures

* When the cause of solidification shrinkage occurs, the same countermeasures as the shrinkage hole countermeasure are taken.

*Reconsideration of alloy species (alloys with small solidification range)

* Improve the cleanliness of the soup by dissolving the soup (removing degassing, deoxidizing, intervening).

* Rethink the type and amount of release agent.

* Appropriate casting conditions (mold temperature, casting pressure, injection speed, solution temperature, etc.)

*Change in product shape.

* Appropriate casting scheme.