Metal casting : part -2

Properties of Moulding sand :

1. Porosity Property

2. Strength

3. Cohesiveness property

4. Adhesiveness

5. Refractoriness

6. Collapsibility

7. Flowability

Fluidity of Molten metal is depends on the -

1. Characteristics of molten metal

2. Casting parameter

1. Characteristics of molten metal :

1. Viscosity

2. Surface tension

3. Inclusion

4. Solidification pattern of the alloy

2. Casting parameter :

1. Mold Design

2. Mold material and it's characteristics

3. Degree of super heat 

4. Rate of pouring

5. Heat transfer rate

Methods of Mould Making :

1. Hand molding

2. Machine molding - 1. Jolting

                                      2. Squeezing

                                      3. Jolting and squeezing

                                      4. Sand slinging

Core Making :

* Cavities and hollow projections

* Cores are normally made by CO2 molding .

Properties of Core Making :

1. Non - metal

2. Free from moisture

3. High strength

4. High collapsibility

Core Print : 

Locating , positioning  and supporting of cores . 

Chaplet :

 * Additional support for supporting the unsupported load  .

* Made by same material .

Chills :

Increasing heat transfer from corner of mould which is possible by providing high thermal conductivity metal piece of the corner of mould is called as chill .

Pad or Padding :

Used to avoid sand erosion .