Diecasting Companies Aluminium Die Casting Alloys

• Basic Considerations For Die Castings
• Fillets, Ribs, And Corners
• Pressure tightness
• Surface Finish, As Cast
• Typical Mechanical Properties Aluminum Alloys
• Typical Physical Properties of Aluminum Casting Alloys
• Annealing and Stress Relieving Aluminum Casting
• Characteristics of Aluminum Alloys
• Memberships

Pressure Tightness

Most die castings can be cast pressure tight. However, in some cases impregnation may be required. Consultation with the die caster in the early design stage is recommended where a requirement for pressure tightness exists in order to take advantage of the basic knowledge of the design and processing factors which will help him to cast pressure tight die casting.

Important considerations relating to the economic production of pressure tight die casting include the following :

1. Design
   Successful casting of pressure tight die castings requires conformance to the principles of good die casting design.
   Recommendations concerning fillets, ribs and corners contained in ADCI Product Standard E15 should be followed very carefully.
   Sections should be as uniform as possible.
   Holes and passage requiring pressure tightness should be cored to reduce the effect of porosity. Ample draft should be allowed in cored holes and passages which are not machined.
   Heavy sections should be avoided.
   
   Careful consideration of the factors of good design will aid in the economical casting of pressure tight die castings.
   
   
2. Machining
   The nature of the die casting process is such that the outer surface of a die casting is usually dense and relatively free from porosity.
   A minimum amount of machining stock should be allowed to avoid cutting deeply into a die casting where porosity may be present.
   Avoid large draft angles which would require the removal of a large amount of stock from surfaces to be machined, particularly where holes are cored.
   Where a large amount of machining must be done, impregnation probably will be required after machining.
   
   
3. Size
   Larger die castings are generally more difficult to cast pressure tight and will require pressure testing by the caster to assure adequate process control. Impregnation is more generally required for large die castings.
   
4. Pressure
   Pressure requirements for die castings are generally in order of  5 to 15 psi. Pressure in excess of 100 psi will require special consideration by the die caster.
   
   
5. Alloy
   Certain alloys are better for making pressure tight die castings. Reference is made to ADCI Product Standard M4 for aluminum alloys (in which comparisons are shown for pressure tightness of various aluminum alloys) to aid in the selection of the favorable alloy.
   
   
6. Pressure Testing
   Reference is made to the last two paragraphs of ADCI Product Standard C8-56.