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 PROPERTIES Guar.R.T. Min. Typical Elevated Temperature Properties
93˚C (200˚F) 204˚C (400˚F) 315˚C (600˚F) 426˚C (800˚F)
Ultimate Strength MPa (ksi) 552 (80) 538 (78) 365 (53) 283 (41) 214 (31)
Yield Strength, 0.2% offset MPa (ksi) 483 (70) 421 (61) 255 (37) 172 (25) 145 (21)
Elongation in 51 mm (2″) gage length (%) 15 23 25 28 26
Reduction in Area – Bar, Billet & Forging only (%) 25
OTHER MECHANICAL PROPERTIES
Stress to Rupture in Time Shown Stress MPa (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) Stress MPa (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 (%) 1 0.1 0.1 1
Charpy V-Notch Impact @ R.T. Joules (ft-lbs) 13 – 27 (10 – 20)
Bend Radius Under 1.78 mm (0.070″) thick 2.5 x Thickness
1.78 mm (0.070″) and over 3.0 x Thickness
Welded Bend Radius 3.0 – 5.0 x Thickness
Nominal Hardness 100 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)
Density g/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 – Tension GPa (103 ksi) 105 (15.2)
Modulus of Elasticity – Torsion GPa (103 ksi) 45 (6.5)
Thermal Conductivity W/m•˚C (BTU/hr•ft•˚F) 17.3 (10.0)
Specific Heat J/Kg•˚C (BTU/lb•˚F) 540 (0.129)
Weldability Good
Industry Specifications ASTM – B265, B348, B381, F67; AMS 4901 and 4921