Solutions to reduce shape, size, and weight errors in cast iron casting due to metal deficiency

Solutions to limit shape, size, and weight errors in cast iron due to metal deficiency
In the cast iron casting process, using green sand molding technology, one of the common technical errors is that the casting has incorrect shape, size, or weight due to metal deficiency. This error occurs when the molten metal does not completely fill the mold cavity, causing the solidified part to lack a portion of its designed shape.
This is a common defect in the production of FC and FCD cast iron, especially for parts with complex shapes or thin walls.
**Causes of deficiency in cast iron casting**
In cast iron casting technology using sand molds, the phenomenon of casting deficiency can arise from various factors during the metal pouring process and the design of the gating system.
1. Insufficient amount of metal poured
If the amount of molten metal poured into the mold is not enough to completely fill the mold cavity, the solidified product will lack a portion of its shape.
2. Low fluidity of cast iron
During the casting process, if the pouring temperature is low or the alloy composition is not optimized, the molten metal can solidify prematurely before filling the mold.
3. Unreasonable gating system design
A gating system with a small cross-section or suboptimal design will reduce the speed and flow rate of molten metal into the mold.
4. Inadequate venting system of the sand mold
In green sand casting, if the mold's venting capability is poor, the increased gas pressure inside the mold will impede the flow of molten metal.
5. Casting wall too thin
Cast iron parts with thin walls can cause the metal to solidify quickly, interrupting the flow and leading to material deficiency in certain areas.
**Solutions to limit defects in green sand casting**
To limit shape and size errors in green sand cast iron, it is necessary to optimize both mold design and production process simultaneously:
- Improve the venting capability of the sand mold by increasing the permeability of the sand mixture or adding a venting system.
- Increase the fluidity of molten cast iron by adjusting the chemical composition and controlling the pouring temperature.
- Standardize the mold assembly and clamping process, ensuring the mold is tight and stable during pouring.
- Optimize the gating system design to ensure molten metal fills the mold quickly and uniformly.
- Adjust product design, increasing wall thickness in areas prone to deficiency.
**DISOCO's green sand cast iron casting capabilities**
To effectively control defects in the cast iron casting process, equipment systems and production processes play a very important role.
DISOCO operates a complete automatic green sand casting line according to Japanese standards, ensuring stable quality and high productivity for FC and FCD cast iron products.
Technical information of the green sand casting line
- Automatic green sand casting line – SINTO (Japan)
- Capacity: 14,000 tons/year
- Molding speed: 30 seconds/mold
- Mold size: 700 × 600 × 500 mm
- Material: FC, FCD cast iron from 1 – 70 kg
- The entire green sand cast iron casting process is automated, including: Sand mixture preparation, Mold making, Molten cast iron pouring into the mold, Demolding and post-casting treatment
In addition, DISOCO is equipped with a comprehensive quality control system, ensuring cast products achieve high dimensional accuracy and mechanical properties:
- Spectrometer for metal composition analysis
- 3D CMM machine for dimensional inspection
- UT (ultrasound) for internal defect inspection
- Hardness / Tensile test for mechanical properties inspection
- Sinto Sand Analyzer for mold sand quality control
Thanks to its modern green sand casting line and strict quality control system, DISOCO is capable of supplying high-quality cast iron products, meeting the stringent requirements of industries such as automotive, machinery, and industrial equipment.