Annex E(informative)Additional info

Annex E(informative)Additional information on the relationship between tensile strength,hardness and wall thickness of grey iron castingsFigure E.1 provides additional general information on the expected relationship between minimum tensilestrength and wall thickness. Figure E.2 provides information on average Brinell hardness and wall thickness ofcastings.Not all castings can be produced in any material hardness grade given in Table 2 for any wall thickness, andthis is reflected in Figure E.2. To meet the requirements of any hardness range, more than one material gradecan be used, depending on the wall thickness involved.This illustrates the importance of reaching an agreement between the manufacturer and the purchaser on thespecification of the hardness required in castings and also the location where a hardness test should becarried out.EXAMPLE A For a casting with a relevant wall thickness of 40 mm grade EN-GJL-300 is selected. For this section ofthe casting a guidance value for the minimum tensile strength of 270 MPa is specified. (see Table D.1). For the samecasting in a 10 mm section, a minimum tensile strength of 346 MPa; and in a 80 mm section, a minimum tensile strengthof 238 MPa can be expected (see Figure E.1).EXAMPLE B For a casting with a relevant wall thickness of 120 mm grade EN-GJL-300 is selected. For this section ofthe casting a guidance value for the minimum tensile strength of 220 MPa is specified. (see Table D.1). For the samecasting in a 80 mm section, a minimum tensile strength of 250 MPa; and in a 200 mm section, a minimum tensile strengthof 212 MPa can be expected (see Figure E.1)