4140 As-Rolled Plate

Analysis Mechanical_Properties Applications Machineability_and_Weldability Heat_Treating Tolerances Speedy Metals items

4140 as-rolled plate is a chromium-molybdenun alloy steel that can be oil hardened to relatively high hardenability. The chromium content provides good hardness penetration, and the molybdenum imparts uniformity of hardness and high strength. Through variations in the method of heat treating 4140, an exceptionally wide range of properties can be attained. For this reason, it is often used as stock for forging, as 4140 has self scaling properties. 4140 responds readily to heat treatment and is comparatively easy to machine in the heat treated condition. 4140 resists creep in temperatures up to 1000° F and maintains its properties even after long exposure at these relatively high working temperatures. Other desirable properties include good wear resistance, excellent toughness and good ductility in the quenched and tempered condition. 4140 can attain high mechanical properties (260,000 psi tensile and 235,000 psi yield) in the hardened condition of 500 Brinell.

ANALYSIS

4140 As-Rolled Plate conforms to ASTM A829

MECHANICAL PROPERTIES

The above values are average and may be considered as representative of 4140 as-rolled plate

APPLICATIONS

4140 can be used for as wide variety of applications where greater toughness and wear resistance is needed over lower carbon grades. Typical applications include strippers, holder blocks, mold bases, ejectors, back up and support tooling, fixtures, jigs, molds, stubs, couplings, reamer bodies, gears, gear racks, valves, chain links, spindles, sprockets, tool bodies, tool holders, tie rods, guides, tracks, ways, slides, wear strips or parts, forming dies, brake dies, trim dies, bolsters, machinery parts and components, etc. This material roll threads, knurls, and may be plated

MACHINEABILITY AND WELDABILITY

4140 has a machinability rating at 66% of B1112. Average cutting speed 110 ft/min. 4140 is difficult to weld, but can be welded by any of the common welding practices providing section is preheated, and stress relieved after welding.

HEAT TREATING

4140 has a hardening range of 1525° -1625° F. Quench in oil. A wide range of mechanical properties can be obtained by tempering between 400° and 1300° F.
Forging
Heat to 2100° to 2200° F
Normalizing
Heat to 1600° - 1700° F. Cool in air. Average BHN 285
Annealing
Heat to 1450° - 1550° F. Cool slowly in furnace. Average BHN 187

TOLERANCES

Thickness

Tolerance Over Specified Thickness, For Widths Given, in Inches
Thickness (Inches) Thru 47 48 to 59 60 to 71 72 to 83 84 to 95 96 to 107 108 to 119 120 to 131 132 to 143 144 to 167
To under 1/4 0.030 0.030 0.030 0.030 0.030 0.030 0.030 0.030 0.040 -
1/4 to under 5/16 0.030 0.030 0.030 0.030 0.030 0.030 0.030 0.040 0.040 -
5/16 to under 3/8 0.030 0.030 0.030 0.030 0.030 0.030 0.030 0.040 0.040 0.050
3/8 to under 5/8 0.030 0.030 0.030 0.030 0.030 0.030 0.040 0.040 0.050 0.060
3/4 to under 1 0.030 0.030 0.030 0.030 0.040 0.040 0.050 0.050 0.060 0.070
1 to under 2 0.060 0.060 0.060 0.060 0.060 0.070 0.080 0.100 0.100 0.110
2 to under 3 0.090 0.090 0.090 0.100 0.100 0.110 0.120 0.130 0.140 0.150
3 to under 4 0.110 0.110 0.110 0.110 0.110 0.130 0.140 0.140 0.140 0.150
4 to under 6 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.150 0.200
6 to under 10 0.230 0.240 0.240 0.240 0.240 0.240 0.240 0.240 0.240 0.270

Tolerance under specified thickness .010" x 3/4 x 52" wide plate, for example, would have a tolerance range of .740-.780"
Because of tolerances, ie thickness, flatness and camber, as well as the hot roll condition, ASTM A36 generally does not finish to specified thickness.

Camber

Permissible camber for sheared and Gas-Cut A36 Plate, All Thicknesses:

Maximum Camber (Inches) = 1/8" x ( Number of feet of length / 5 )

Flatness

For all plates, the longest dimension is considered the length, and flatness tolerance along the length should not exceed the amounts indicated below the specified width and thickness in plate though 12' in length or longer. The flatness variations across the width should not exceed the tabular amount for the specified width

Flatness Tolerances For Specified Widths, in Inches 
(Maximum deviation from a horizontal flat surface)
Thickness Lbs/Sq. FT > 36 36 > 48 48 > 60 60 > 72 72 > 84 84 > 96 96>108
Under 1/4" > 10.2# 0.813 1.125 1.375 1.875 2.000 2.250 2.375
1/4 to under 3/8 10.2 > 15.3 0.750 0.938 1.125 1.375 1.750 1.875 2.000
3/8 to under 1/2 15.3 > 20.4 0.750 0.875 0.938 0.938 1.125 1.313 1.500
1/2 to under 3/4 20.4 > 30.6 0.625 0.750 0.813 0.875 1.000 1.125 1.250
3/4 to under 1 30.6 > 40.8 0.625 0.750 0.875 0.875 0.938 1.000 1.125
1 to under 2 40.8 > 81.7 0.563 0.625 0.750 0.813 0.875 0.938 1.000
2 to under 4 81.7 > 163.4 0.500 0.563 0.688 0.750 0.750 0.750 0.750
4 to under 6 163.4 > 245.0 0.563 0.688 0.750 0.750 0.875 0.875 0.938
6 to under 8 245.0 > 326.7 0.625 0.750 0.750 0.938 1.000 1.125 1.250

SPEEDY METALS ITEMS

1/4" 4140 Hot Rolled, As-Rolled, Plat 3/8" 4140 Hot Rolled, As-Rolled, Plat 5/8" 4140 Hot Rolled, As-Rolled, Plat
1" 4140 Hot Rolled, As-Rolled, Plat 1-1/4" 4140 Hot Rolled, As-Rolled, Plat 1-3/8" 4140 Hot Rolled, As-Rolled, Plat
1-1/2" 4140 Hot Rolled, As-Rolled, Plat 1-3/4" 4140 Hot Rolled, As-Rolled, Plat 2" 4140 Hot Rolled, As-Rolled, Plat
2-1/4" 4140 Hot Rolled, As-Rolled, Plat 2-1/2" 4140 Hot Rolled, As-Rolled, Plat 2-3/4" 4140 Hot Rolled, As-Rolled, Plat
3" 4140 Hot Rolled, As-Rolled, Plat 4-1/4" 4140 Hot Rolled, As-Rolled, Plat 4-1/2" 4140 Hot Rolled, As-Rolled, Plat