Materials Produced

SG Iron - Ductile Iron

Ductile Iron is also known as Ductile Cast iron, Nodular Cast Iron, SG Iron, Spheroidal Graphite Iron and Spherulitic Cast Iron. This grade of Iron was developed over 60 years ago and in USA. As the name Ductile Iron suggests this grade of Cast Iron has a degree of ductility.

The main characteristic of this material is the structure of the graphite. In Ductile Cast Iron the graphite is in the form of spherical nodules (hence the name Spheroidal Graphite) rather than flakes as in Grey Cast Iron. This nodular graphite structure inhibits the creation of linear cracks hence the ability to withstand distortion.

As with Grey Cast Iron, there are many grades of SG Iron- Ductile Iron that can be specified offering the engineers varying degrees of tensile strength and elongation. The various grades are achieved through a combination of alloy additions and heat treatment.
This material offers the following benefits:-

 

Cost

When compared against steel castings SG Iron-Ductile Iron has a lower manufacturing cost.

 

Castability

SG Iron-Ductile Iron has a lower casting temperature than steel and this allows for a superior surface finish and the ability to cast complex shapes incorporating changes of section.

 

Ductility

Some grades of SG Iron-Ductile Iron offer elongation figures in excess of 20%.

 

Machining

SG Iron-Ductile Iron is very easily machined and machining allowances are able to be kept to a minimum.

 

Tensile Strength

Grades of SG Iron-Ductile Iron offer tensile strengths of up to 900N/mm2.

 

Weight Reduction

SG Iron-Ductile Iron castings will weigh significantly lighter than the equivalent steel casting due to density, less machining allowance and the ability to cast to shape.

 

 

 

SG Iron Specification EN1563 (previously BS2789)

 

Material Designation	Tensile Strength (min) N/mm2	0.2% Proof Stress (min) N/mm2	Elongation (min) %	Minimum impact resistance values (in j), see note A						Predominant Structure
				At room temperature (23 +/- 5) degrees C		At (-20 +/- 2) degrees C		At (-40 +/- 2) degrees C
				Mean value from 3 tests	Individual value	Mean value from 3 tests	Individual value	Mean value from 3 tests	Individual value
EN-GJS-350-22-LT	350	220	22	-	-	-	-	- 12	- 9	Ferrite
EN-GJS-350-22-RT	350	220	22	- 17	- 14	-	-	-	-	Ferrite
EN-GJS-350-22	350	220	22	-	-	-	-	-	-	Ferrite
EN-GJS-400-18-LT	400	240	18	-	-	- 12	- 9	-	-	Ferrite
EN-GJS-400-18-RT	400	250	18	- 14	- 11	-	-	-	-	Ferrite
EN-GJS-400-18	400	250	18	-	-	-	-	-	-	Ferrite
EN-GJS-400-15	400	250	15	-	-	-	-	-	-	Ferrite
EN-GJS-450-10	450	310	10	-	-	-	-	-	-	Ferrite
EN-GJS-500-7	500	320	7	-	-	-	-	-	-	Ferrite - Pearlite
EN-GJS-600-3	600	370	3	-	-	-	-	-	-	Pearlite - Ferrite
EN-GJS-700-2	700	420	2	-	-	-	-	-	-	Pearlite
EN-GJS-800-2	800	480	2	-	-	-	-	-	-	Pearlite
EN-GJS-900-2	900	600	2	-	-	-	-	-	-	Pearlite or Tempered Martensite

 

Note A: The lower impact value specified is for wall thickness up to 60mm on EN-GJS-350-22-LT and EN-GJS-350-22-RT and 30mm to 60mm on
EN-GJS-400-18-LT and EN-GJS-18-RT.
The higher impact values are all based on wall thickness of 60mm to 200mm.