4. cont casting, furnaces, deffects

Cont

inuo

us C

astin

g

Various furnaces used in FOUNDRY PRACTICE

• Blast Furnace

• BOF

• Cupola

• Oxygen Lance Furnace

• Electric Arc Furnace

• Induction Furnace

Crucible furnace

Cupola

Electric Arc Furnace

Induction furnace

Pouring vessel

Casting defects

• Gas defects:Blow holes and open blows; air inclusions, pin hole porosity

• Shrinkage cavity:

• Mold material defect:Cuts and washes, metal penetration, fusion, run out, rat tails and bucklsswells, drop

• Pouring metal defects:Mis-runs, cold-shuts, slag inclusion

• Metallurgical defects:hot tears, hot spots

Microporosity

Surface defects

Internal defects Internal defects

Inspection Techniques of Castings• Visual Inspectionrough surface, obvious shifts, shift of core etc

• Pressure testmicro leak detection

• Magnetic Particle Inspectionsubsurface voids, cracks etc

• Dye-penetrant Inspectioninvisible surface defects in a non-magnetic casting

• Radiographic examinationvoids, non metallic-inclusions, hot tears, cracks, porosity

• Ultrasonic Inspection• SEM