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EN-GJS-450-18 (Ultra-Ductile Ferritic SG Iron)

GJS-450-18 -- fully ferritic ductile iron with the highest elongation of the mid-strength SG iron grades. A>=18%, Rm>=450 MPa. For pipe fittings, pump housings and components requiring maximum ductility combined with moderate strength.

Cast Iron Spheroidal Graphite Cast Iron ENEN-GJS-450-18 ISOISO 1083 Grade 450-18 ASTMA536 Grade 65-45-15 (nearest, slightly lower elongation spec) JISFCD450-18 (nearest) +1
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Description

EN-GJS-450-18 per EN 1563. Fully ferritic matrix (lower Si than GJS-400-18 in some formulations, tightly controlled Mg and rare-earth treatment) gives A>=18% -- exceptional ductility for a 450 MPa-class iron. Standard for ductile iron pipe fittings, pump and valve bodies, and any application combining pressure-containment with impact/ductility requirements exceeding standard GJS-400-15.

Key Properties — As Cast (fully ferritic)
Rm (Tensile Strength)
450 – 570
MPa
Re / Rp0.2 (Yield)
320
MPa
A₅ (Elongation)
≥ 18.0
%
Hardness
150 – 200
HB
E (Young's Modulus)
169
GPa
Density
7.10
g/cm³
Main Designations (5)
Standard BodyDesignationCountry / RegionNote
EN EN-GJS-450-18 EU
ISO ISO 1083 Grade 450-18 International
ASTM A536 Grade 65-45-15 (nearest, slightly lower elongation spec) USA
JIS FCD450-18 (nearest) Japan
JUS Duktilni.450-18; nema direktnog JUS Yugoslavia/BiH Sfero-liv max duktilnosti 450-18
Standards (5)
#Standard BodyDesignationCountry / RegionNote
1 EN EN-GJS-450-18 EU —
2 ISO ISO 1083 Grade 450-18 International —
3 ASTM A536 Grade 65-45-15 (nearest, slightly lower elongation spec) USA —
4 JIS FCD450-18 (nearest) Japan —
5 JUS Duktilni.450-18; nema direktnog JUS Yugoslavia/BiH Sfero-liv max duktilnosti 450-18
All values in wt.%
C
Carbon (total)
3.5000 – 3.8000
Si
Silicon
2.7000 – 3.2000
Mn
Manganese
≤ 0.3000
Mg
Magnesium (nodulariser)
0.0300 – 0.0600
ElementSymbolMin %Max %Typical %
Carbon (total) C 3.5000 3.8000 3.6500
Silicon Si 2.7000 3.2000 2.9500
Manganese Mn — 0.3000 0.1800
Magnesium (nodulariser) Mg 0.0300 0.0600 0.0450
Mechanical Properties
ConditionCode Rm min
MPa		Rm max
MPa		 Re min
MPa		Re max
MPa		 A₅ min
%		 Z
%		 KV
J		 HB minHB max HRC minHRC max E
GPa
As Cast (fully ferritic) +F 450 570 320 — 18.0 — — 150 200 — — 169.0
Physical Properties
Density
7.100
g/cm³
Melting Point
1150–1210
°C
Young's Modulus
169.0
GPa
Poisson's Ratio
0.275
—
Thermal Conductivity
34.0
W/m·K
Thermal Expansion
12.50
×10⁻⁶ /K
Specific Heat
460
J/kg·K
Electrical Resistivity
0.5600
µΩ·m
Magnetic
Yes
 
Heat Treatment
Ferritising Anneal
Temperature:900°C – 950°C
Medium:Furnace
Duration:2-4 h
Cooling:Furnace cool to 720 C then air
Hardness After:Fully ferritic matrix / max elongation
Ensures complete pearlite elimination for maximum ductility.
Stress Relieving
Temperature:500°C – 560°C
Medium:Furnace
Duration:2-4 h
Cooling:<=30 C/h
Hardness After:+-5 HB
For precision castings.
NOT for high-strength applications
Medium:A>=18% priority sacrifices some strength ceiling vs GJS-500-7
Duration:N/A
Cooling:N/A
Hardness After:N/A
Choose GJS-500-7 or higher where strength is the primary driver.
Machinability
Machinability Rating
relative to AISI B1112 = 100%
60.0%
Moderate
Turning Speed (HSS)
46
m/min
Turning Speed (Carbide)
205
m/min
Feed Rate (Turning)
0.200
mm/rev
Drilling Speed (HSS)
32
m/min
Milling Speed (Carbide)
210
m/min
CoolantDry or flood
Chip FormationShort chips -- excellent machinability due to fully ferritic matrix
Tool MaterialCarbide K10/K20; HSS acceptable
Surface FinishRa 0.8-3.2 um
Excellent machinability -- among the best of the SG iron grades.
Applications
Pipe Fittings
Ductile iron pipe fittings requiring high ductility for installation flexing and impact resistance.
Pump Housings
Pump and valve bodies where combined pressure containment and ductility are needed.
Impact-Resistant Castings
Components subject to occasional impact loading where brittle fracture must be avoided.
Technical Notes
✅
GJS-450-18 vs GJS-400-15 vs GJS-500-7
GJS-400-15: A>=15%, Rm>=400 MPa, standard ferritic. GJS-450-18: A>=18%, Rm>=450 MPa, higher strength AND higher ductility than 400-15 through tighter process control. GJS-500-7: A>=7%, Rm>=500 MPa, favours strength over ductility. GJS-450-18 represents a genuine improvement over 400-15 rather than a trade-off.