EN-GJL-250 is a high material grade of grey cast iron in European standard EN 1561, it is also named as cast iron GG
The followings are its equivalent grades, chemical composition, mechanical properties, and some photos of grey iron castings made by Dandong Foundry.
EN-GJL-250, GG25 Equivalent Grades
ISO 185 - Class 250
GB 9439 - HT
ASTM A48 - Class
UNI 5007 - G
UNF - FG
AS 1830 - T
NS11 100 - SJG
EN-GJL-250, GG25 Chemical Composition
The normal chemical composition should be C = 2.8-3.3, Si = 1.2-1.7, Mn = 0.8-1.2, P ≤ 0.15, S ≤ 0.12.
Please notice, the chemical composition can not be taken as material quality inspection standard. In all standards, the chemical composition is just for reference. The grey iron foundries could adjust their composition according to their own production condition and experience, as long as they could guarantee to meet the mechanical properties, which is the only inspection standard.
However, if the iron castings need to meet special application, so will require the specific chemical composition, then the buyers should denote this requirement clearly, and the grey iron foundries should take it as the quality standard.
EN-GJL-250, GG25 Mechanical Properties
Tensile Strength ≥ 250 Mpa
Yield Strength: No Requirement.
Only the tensile strength is the quality inspection standard. Other mechanical properties are only for reference unless the buyers have particular requirements.
EN-GJL-250, GG25 Grey Iron Castings
This grade has comparatively high tensile strength, and will not need additional heat treatment, so its production cost is still kept low. However, its hardness is comparatively high, so as for the castings parts with thin wall thickness, the hardness for some positions will be very high, over 200 BH, therefore, will cause difficulty to machining, especially to drilling and milling.
Moreover, will cause the casting parts more crispy. So, if the lower tensile strength could meet your use, better to choose lower grade EN-GJL-200, GG20.