Casting is a highly technical process involving materials, equipment, processes, and safety. Mastering the correct usage techniques can not only improve casting quality but also ensure production safety and extend equipment life. The following are key techniques summarized based on practical application:
Molding and Mold Handling Techniques
Appropriate Parting Surface Selection: Place the entire casting within the same sand box to reduce the risk of misalignment; the parting surface should ideally be selected at the largest cross-section for easy demolding.
Mold Sand Performance Control:The molding sand must possess sufficient strength, permeability, and refractoriness. The molding sand should be uniform and compact to avoid localized softness that could lead to mold collapse or bulging.
Mold Removal Operation Standards:Before removing the mold, moisten the edges of the pattern with water (not too much) to prevent sand adhesion and damage to the mold cavity.
When using demolding pins or a crane, ensure balanced force, tapping and lifting simultaneously to prevent mold cavity breakage.
Key Controls in Melting and Casting
Precise Control of Molten Metal Temperature: Casting temperature is generally controlled between 1260~1400℃:
Too high temperature: Easily causes porosity, shrinkage cavities, and sand adhesion.
Too low temperature: Poor fluidity, leading to defects such as incomplete filling and cold shuts.
Ladle Preheating and Slag Retention:The ladle must be dried to prevent moisture from causing molten metal splashing; use slag retainers during casting to prevent slag from entering the mold cavity.
Stable Casting Speed: Adopt a "slow-fast-slow" rhythm: start slowly to prevent scouring the mold cavity, speed up in the middle to ensure complete filling, and slow down at the end to reduce impact.
