EN-GJL-250 is the EN 1561 grey cast iron grade with a 250 MPa minimum tensile strength, perlite-dominant matrix, and typical Brinell hardness of 170 to 230 HB [S4]. EN-GJS-500-7 is the EN 1563 ductile iron grade carrying 500 MPa minimum tensile, 320 MPa minimum 0.2 percent proof strength, 7 percent minimum elongation, and 170 to 230 HB hardness in a ferrite-pearlite structure [S4][S3].
The two grades sit on opposite sides of the cast-iron property spectrum: flake graphite gives EN-GJL-250 high damping but near-zero ductility, while nodular graphite gives EN-GJS-500-7 measurable elongation and significantly higher yield strength. For valve bodies, pump housings, and machine-tool beds, EN-GJL-250 remains common; for safety-critical or pressure-containing components, EN-GJS-500-7 is the typical minimum ductile grade [S4].
Mechanical properties and structure (EN 1561 and EN 1563)
EN 1561 grades are tensile-strength-graded grey irons; the suffix number is the minimum tensile in MPa on a separately cast test bar. EN-GJL-250 specifies 250 to 350 MPa tensile, 0.3 to 0.8 percent elongation, 170 to 230 HB, and a pearlite matrix suitable for moderate wear and good damping [S4][S3].
EN 1563 grades add proof strength and elongation to the designation. EN-GJS-500-7 reads as 500 MPa minimum tensile, 320 MPa 0.2 percent proof, 7 percent minimum elongation, 170 to 230 HB, ferrite-pearlite matrix [S4]. The 0.2 percent proof of 320 MPa is roughly double the practical proportional limit of EN-GJL-250, which behaves elastically up to roughly 165 to 228 MPa in the Rp0.1 range before microcracking in the graphite flakes initiates [S3].
Hardness alone is not a reliable substitute grade. EN-GJL-250 and EN-GJS-500-7 share the 170 to 230 HB window, yet their elongation differs by an order of magnitude, so any HB-only substation for a ductile-iron part on a grey-iron base metal is a specification error [S4].
Cross-standard equivalents of EN-GJL-250
EN-GJL-250 maps cleanly to DIN 1691 GG25 (the predecessor designation now retired in favour of EN 1561), ISO 185/JL/250, AS 1830 grade 250, ASTM A48 Class 35, JIS G5501 FC250, UNI 5007 G25, BS 1452 grade 250, and GB 9439 HT250 [S1][S2]. The DIN W-Nr 0.6025 material number is also commonly listed against EN-GJL-250 in foundry datasheets [S2].
ASTM A48 Class 35 is the standard transatlantic substation for general engineering castings; ASTM A126 Class B is a different family, used specifically for valves, flanges, and pressure fittings, and should not be assumed equivalent on chemistry or test-bar geometry [S1]. For pressure-retaining parts, ASTM A126 dictates the bar-stock and testing regime even where EN-GJL-250 would otherwise be specified.
For European projects still carrying DIN 1691 references, GG25 is the historical equivalent and remains accepted in MRO and legacy documentation, but new specifications should call out EN 1561 EN-GJL-250 explicitly to avoid ambiguity in the as-cast tensile range 250 to 350 MPa [S1][S4].
Cross-standard equivalents of EN-GJS-500-7
EN-GJS-500-7 corresponds to ISO 1083/JS/500-7/S, DIN 1693 GGG50, ASTM A536 80-55-06 (or 80-60-03 in some U.S. references), JIS G5502 FCD500, AS 1831 500-7, BS 2789 500/7, GB 1348 QT500-7, UNI 4544 GS500-7, NF A32-201 FGS500-7, and IS 1865 SG500/7 [S1][S3].
The 80-55-06 / 80-60-03 ASTM A536 pair is a common source of confusion: 80-55-06 reads as 80 ksi tensile, 55 ksi yield, 6 percent elongation, while 80-60-03 reads 80 ksi tensile, 60 ksi yield, 3 percent elongation. EN-GJS-500-7's 7 percent elongation at 500 MPa (about 72.5 ksi) aligns most closely with 80-55-06 on elongation grounds, so a spec calling EN-GJS-500-7 should not be downgraded to an 80-60-03 melt without explicit engineering approval [S1]. A wider spec decision map for the A536 family is laid out in ASTM A536 60-40-18 vs 80-55-06: Spec Decision Map for Ductile Iron Castings.
For projects specifying JIS FCD500 or GB QT500-7, mechanical targets align, but melt practice (Mg treatment residual, section-size sensitivity, and ferrite/pearlite ratio) shifts; foundries should be qualified on the relevant test-bar geometry, not just on the alphanumeric code.
Selection criteria: when EN-GJL-250 is the right call
EN-GJL-250 is preferred where vibration damping, machinability rating, compressive strength, and low cost dominate, and where the part is statically loaded in compression. Typical applications include machine-tool beds, gearboxes, pump housings, brake components, and diesel engine blocks, where the flake graphite network absorbs vibration that would otherwise be transmitted through the structure [S4].
Specify EN-GJL-250, not a ductile grade, when: (1) the part relies on damping rather than impact resistance; (2) wall thickness exceeds roughly 50 mm and the section-size penalty on ductile iron elongation is unacceptable; (3) the casting is exposed to thermal cycling and growth, where grey iron's lower modulus reduces stress; (4) the section is heavy and price-sensitive. Sand-casting foundries typically pour EN-GJL-250 routinely, and the conveyor and bulk-material handling articles show how grey iron housings are still default for many bulk-handling components.
Avoid EN-GJL-250 when: (1) the part is a pressure-retaining shell in a fitness-for-service regime, where EN-GJS-500-7 or higher is the modern norm; (2) impact or shock loading is expected, since 0.3 to 0.8 percent elongation is essentially brittle behaviour [S4]; (3) the casting must meet ductile-failure requirements for safety, such as lifting eyes or load-bearing truck crane components [S4].
Selection criteria: when EN-GJS-500-7 is the right call
EN-GJS-500-7 is the workhorse ductile iron for parts that need real elongation (7 percent minimum) and roughly double the yield of EN-GJL-250. Common uses include valve bodies, pump casings, hydraulic cylinders, hubs, brackets, and rotating components subject to bending or shock [S4].
Specify EN-GJS-500-7 when: (1) the part must show measurable ductility under overload, e.g. lifting or suspension hardware, where brittle fracture is unacceptable; (2) the casting is a pressure-retaining shell under PED or similar regimes, since 320 MPa 0.2 percent proof gives design margin; (3) section size is moderate (up to about 50 mm), where the 7 percent elongation target is reliably achieved; (4) weldability or repair-weld acceptability is a procurement requirement, where the nodular matrix behaves more predictably than flake graphite.
Avoid EN-GJS-500-7 when: (1) the part is a heavy section (above roughly 100 mm) where pearlite-promoting cooling and lower elongation are accepted as a trade for machinability; (2) cost is the dominant driver and no ductility requirement exists, where the higher magnesium treatment and inoculation cost of ductile iron cannot be recovered; (3) vibration damping is the design driver, since ductile iron damps at roughly 20 to 50 percent of grey iron depending on graphite form.
Side-by-side comparison: EN-GJL-250 vs EN-GJS-500-7
The following table condenses the decision-critical parameters. All values are minimum on separately cast test bars per EN 1561 and EN 1563. [S1]
EN-GJL-250: tensile 250 to 350 MPa; 0.2 percent proof is not specified, Rp0.1 in the 165 to 228 MPa range reported in foundry data; elongation 0.3 to 0.8 percent; hardness 170 to 230 HB; matrix pearlite; graphite form flake; damping behaviour very high; relative cost lower; typical use machine-tool beds, pump housings, brake parts [S4][S3].
EN-GJS-500-7: tensile 500 MPa minimum; 0.2 percent proof 320 MPa; elongation 7 percent minimum; hardness 170 to 230 HB; matrix ferrite-pearlite; graphite form nodular; damping behaviour moderate; relative cost higher due to Mg treatment; typical use valve bodies, hubs, lifting and pressure-retaining parts [S4].
The hard rule embedded in the table: EN-GJL-250 and EN-GJS-500-7 share a hardness window but are not interchangeable on any safety-relevant service. A grey-iron valve body specified for ductile-iron service is a brittle-fracture risk; a ductile-iron machine-tool bed is a vibration-damping failure [S4].
Limitations, failure modes, and standard traps
Wall-thickness sensitivity is the most common specification trap. EN-GJS-500-7's 7 percent elongation is achieved on a standard test bar (roughly 25 mm); on heavy sections (above about 50 to 100 mm) pearlite fraction rises and elongation falls below the 7 percent minimum, so the spec must call out the relevant test-bar geometry or, for heavy sections, accept a lower elongation class such as EN-GJS-500-7 in BS 2789 with controlled pearlite [S1].
EN 1561 EN-GJL-250 has no minimum proof strength, only tensile. Engineers converting from EN-GJS-500-7 to EN-GJL-250 on cost grounds should not assume the same allowable stress, since grey iron's effective proportional limit is governed by flake-tip cracking, not by a yield plateau [S3][S4].
Cross-standard conversion is safe for static, ambient-temperature, non-pressure service. For pressure equipment, lifting gear, or sour-service applications, conversion requires a fitness-for-service review; the EN 1563 designation alone does not guarantee compliance with NACE MR0175 / ISO 15156 sour-service limits, and the standard does not replace a project-specific material specification.
Procurement and traceability notes
For European procurement, insist on EN 1561 or EN 1563 marking, plus the casting's test-bar geometry and the as-cast tensile result. Castings produced to withdrawn DIN 1691 (GG) or DIN 1693 (GGG) codes should be accompanied by a transitional certificate referencing EN 1561 or EN 1563 to avoid ambiguity [S1].
Foundry test reports should report each of: tensile strength, 0.2 percent proof, elongation, Brinell hardness, and matrix structure. Suomivalimo's iron grade reference lists EN-GJL-250 at 250 MPa minimum with 103 to 118 HB lower bound for thinner sections, illustrating the wall-thickness effect within the same nominal grade [S3]. Buyers should not accept a "meets EN-GJL-250" statement without the test-bar size and the per-heat result.
On the equipment side, grey-iron and ductile-iron castings are typically produced in sand casting and related processes; the article on cold box core shooter: shot chamber capacity and blow pressure range explains the core-making window that controls surface finish on these grades, while continuous 360° slewing vs rack and pinion on loader cranes shows where ductile iron EN-GJS-500-7 is increasingly specified for slewing rings that were historically grey iron. A third relevant angle, dimensional tolerance and process control on iron castings, is covered by the same family of references at the industrial valve and construction machinery and equipment catalog pages.
The underlying component specifications are covered under lamps and light fittings.