● Semi-Solid Forming
Technology ?
Semi-Solid
Metal(SSM) as we know it today, evolved out of a series of studies
performed by Professor M.C Flemings and his graduate students
at MIT in the late 1960s and early 1970s. It is a highly volume
manufacturing process that produces aluminum, magnesium and copper
alloy components for precision and performance applications. Specially
prepared metal slugs are gradually heated to a semi-solid state
kept at a temperature between the solidus and liquidus isotherms.
Then they are transferred to the forming machine,where a ram injects(or
squeezes) the metal into die,under pressure.Once solid,the die
opens and the part is ejected.
The advantages of SSM include net shape or near net shape manufacturing,
the ability to perform thin walls, excellent surface finish,tight
tolerances and dimensional repeatability.These benefits make it
ideal for use in automobiles, bicycles, marine equipment and golf
clubs. The SSM process produces complex parts with better quality
when compared to parts made by similar processes. The process
combines the advantages of both liquid metal casting and solid
metal forging.
● Advantages
of Aluminum Semi Solid Forming products
1.Effective to form complicated
products and to minimize secondary processing
2. Heat treatable.(Die-casting products can not be heat-treated)
3. Easily weldable to other parts
4. Good mechanical properties(much better than Die Casting products)
5. No pin-hole, blowhole or pore(suitable for pressure resistant
parts)
6. No problem to form hypereutectic alloy excessive silicon content(Suitable
for the products requiring high wear resistance)
7. Reduced dimensional variation due to much reduced residual
stress and solidification shrinkage
● 제조방법에 따른 금속의 미세조직
비교
|
SSF products
have a excellent mechanical
properties than other forming method.
|
|
|
|
SSF:
Uniform & random microstructure due to
electromagnetic stirration
|
Casting:
Dendrite microstructure |
|
|
|
Forging:
Broken dendrite microstructure due to forging
|
Die
Casting: Microstructure with
many porosities due to high gas pressure
|
● System
Flow
