Grade 4

Datasheet
ASTM Grade (UNS No.)GRADE 4 (R50550)
Chemical Composition (Max. values unless range is shown)(wt. %)0.08C; 0.05N; 0.40O; 0.50Fe; 0.015H
TENSILE PROPERTIESGuar.R.T. Min.Typical Elevated Temperature Properties
93˚C (200˚F)204˚C (400˚F)315˚C (600˚F)426˚C (800˚F)
Ultimate StrengthMPa (ksi)552 (80)538 (78)365 (53)283 (41)214 (31)
Yield Strength, 0.2% offsetMPa (ksi)483 (70)421 (61)255 (37)172 (25)145 (21)
Elongation in 51 mm (2″) gage length(%)1523252826
Reduction in Area – Bar, Billet & Forging only(%)25
OTHER MECHANICAL PROPERTIES
Stress to Rupture in Time ShownStressMPa (ksi)462 (67)330 (48)200 (29)241 (35)
Time-Hrs. at Temp. (˚C)1,000 (25)10,000 (100)1,000 (315)10,000 (250)
Stress &Time to Produce Elongation Shown (creep)StressMPa (ksi)283 (41)188 (27)116 (17)200 (29)
Time-Hrs. at Temp. (˚C)1,000 (25)1,000 (100)1,000 (200)1,000 (315)
Creep(%)10.10.11
Charpy V-Notch Impact @ R.T.Joules (ft-lbs)13 – 27 (10 – 20)
Bend RadiusUnder 1.78 mm (0.070″) thick2.5 x Thickness
1.78 mm (0.070″) and over3.0 x Thickness
Welded Bend Radius3.0 – 5.0 x Thickness
Nominal Hardness100 HRB
PHYSICAL PROPERTIES
Nominal Beta Transus°C (°F)949 (1740)
Coefficient of Thermal Expansion 10-6/˚C (10-6/˚F)0-100˚C (32 -212˚F)8.6 (4.8)
0-315˚C (32-600˚F)9.2(5.1)
0-538˚C (32-1000˚F)9.7 (5.4)
0-648˚C (32-1200˚F)10.1 (5.6)
0-816˚C (32-1500˚F)10.1 (5.6)
Densityg/cm3 (lbs/in3)4.51(0.163)
Melting Point, Approx.°C (°F)1660 (3020)
Electrical Resistivity @ R.T.10-6 ohm•cm (10-6 ohm•in)60 (24)
Modulus of Elasticity – TensionGPa (103 ksi)105 (15.2)
Modulus of Elasticity – TorsionGPa (103 ksi)45 (6.5)
Thermal ConductivityW/m•˚C (BTU/hr•ft•˚F)17.3 (10.0)
Specific HeatJ/Kg•˚C (BTU/lb•˚F)540 (0.129)
WeldabilityGood
Industry SpecificationsASTM – B265, B348, B381, F67; AMS 4901 and 4921