Metal Expansion Penetration on Concave Casting Surfaces of Grey Cast Iron Cylinder Heads

• Cylinder heads have an extremely complex shape with large areas of concave casting surfaces. The concave casting surfaces are often associated with metal expansion penetration problems or other surface defects, e. g. surface shrinkage. The defects cause high production costs due to component rejection and increased fettling time. This report presents an investigation of the microstructure in grey cast iron close to the sand-metal interface affected by metal penetration in a complex shaped casting. The dominant penetration defect observed in the cylinder heads was expansion penetration. Even pre-solidification penetration and sand crack defects were observed. The microstructure found in the non penetrated areas is typical for solidification of grey iron cast in sand moulds.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Teknisk mekanik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Applied Mechanics (hsv//eng)

Nyckelord

Grey iron

Cylinder head

Primary austenite

Hot spot

Metal expansion penetration

Surface shrinkage

Dendrite

Inoculation

Technology (byts ev till Engineering)

Teknik

Publikations- och innehållstyp

vet (ämneskategori)

rap (ämneskategori)