Tambíen es llamada fundición laminar
Composicion:
• Carbón (C): de 2.53% a 4%
• Silicio (Si): de 1% a 3%
Propiedades:
• La presencia de grafito le da el color gris.
• Contiene silicio para estabilizar el grafito.
• La rapidez de enfriamiento, afecta la grafitación, dando lugar distintas clases. Un enfriamiento rápido
da lugar a la fundició gris perlítica, y uno lento a ferrítica. Si el proceso es muy rápido o la
grafitación no se realiza, se produce cementita llamada fundición de hierro blanca.
• La resistencia a la tensión y choque es menor que en el acero, pero su tensión a compresión es comparable a
un bajo o medio acero al carbono.
| A48 20B/25B | EN 1561 EN-GJL-150 | DIN 1691 GG-15 |
| A48 25B/30B | EN 1561 EN-GJL-200 | DIN 1691 GG-20 |
| A48 35B/40B | EN 1561 EN-GJL-250 | DIN 1691 GG-25 |
Normas de fundición Gris en válvulas
ASTM A126 - 04(2009)
Standard Specification for Gray Iron Castings for Valves, Flanges, and Pipe Fittings
Esta guía cubre las especificaciones de la normativa de tres clases de fundición gris para la fundición de
partes a presión de una válvula, accesorios a tuberías, y bridas. Análisis químicos deben ser efectuados en cada lote y deben confirmar
los requisitios de composición química de fósforo y sulfuro. Los tests de tensión deben ser realizados para cada clase
de fundición de hierro gris y deben de estar de acuerdo a las tensiones especificadas. Las muestras del test de tensión
deben tener finales roscados y las dimensiones acordadas en la norma.
ASTM A278 / A278M - 01(2006)
Standard Specification for Gray Iron Castings for Pressure-Containing Parts for Temperatures Up to 650°F (350°C)
This specification covers gray iron for castings suitable for pressure-containing parts at elevated temperatures. Castings shall be stress-relieved by placing them in a
suitable furnace and heating them uniformly to the temperatures and for the times specified. Castings to be used at a particular temperature range shall undergo heat treatment
and cooling. Chemical analysis shall be performed on each class of castings and shall meet the maximum requirement for carbon, phosphorus and sulfur. Iron used in supplying castings
shall conform to the required tensile strength. Separately cast test bars having the required dimensions shall be poured from the same lot as the castings represented.
The test bars shall be cast in dried siliceous sand molds maintained at approximately room temperature. Tension test shall be performed on each lot and materials shall conform to
the tensile requirements specified.
ASTM A48 / A48M - 03(2008)
Standard Specification for Gray Iron Castings
This specification covers gray iron castings intended for general engineering use where tensile
strength is a major consideration. Castings are classified on the basis of the tensile strength of the
iron in separately cast test bars. The surface of the casting shall be free of adhering sand, scale, cracks,
and hot tears, as determined by visual examination. The test bars are designated into S, A, B, and C categories,
according to the thickness of its controlling wall section. The casting shall be subjected to a tension test
to determine its tensile strength
EN 1561
Founding - Grey Cast Irons
ISO 185:2005
Grey cast irons -- Classification
ISO 185:2005 specifies the properties of unalloyed and low-alloyed grey cast irons used for castings, which have been manufactured in sand moulds or in moulds with comparable thermal behaviour.
ISO 185:2005 specifies the characterizing properties of grey cast iron by either the tensile strength of separately cast samples, or if agreed by the manufacturer and the purchaser, of cast-on
samples or samples cut from a casting, or if agreed between the manufacturer and the purchaser, the hardness of the material measured on castings or on a cast-on knob.
