Alloy Steel Guide


4140 PH/HT Alloy Steel

A chromium-molybdenum, medium carbon alloy steel, 4140 is used in a wide variety of applications requiring high strength and toughness. The chromium imparts good hardness penetration while molybdenum provides hardness uniformity and strength. In the heat treated or prehard conditions it is in the 24-32 Rockwell C range and stress relieved to minimize warping during machining. Localized hardness may also be imparted by flame or induction hardening. Primarily used in press brake dies, 4140 is also a good choice for applications requiring greater toughness than mild steel. Other typical applications include: bolts, molds, stripper plates, slides, ejector plates, jigs, fixtures, punch plates, drill collars, couplings, axle shafts, valves, machinery shafts, reamer bodies, machine stops.

Typical Analysis:

Carbon
.38/.43
Sulfur
.040 max
Phosphorus
.035 max
Molybdenum
.15/.25
Chromium
.80/1.00
Silicon
.15/.35
Manganese
.75/1.00
Temp. °F
Normalizing 1600-1700
Annealing 1450-1550
Hardening 1525-1625
Tempering 400-1200
Rockwell C
25-42
Mechanical Properties
Tensile Strength 130 ksi
Yield Point 120 ksi
Elongation 2" % 21
Red. Area % 65
Hardness Brinell 245-300
Hardness Rc 24-32
Machinability % na













8620 Alloy Steel

This chromium-molybdenum-nickel "triple alloy" is a widely used case hardening alloy grade. Used where high surface hardenability and tough core is desired along with easy machinability and excellent wear resistance. The chromium and molybdenum contribute to hardness penetration while the nickel increases the toughness. Typical applications include: gauges, jigs, gears, piston rods, plastic molds, cams, pinions, spline shafts.

Typical Analysis:

Carbon
.18/.23
Sulfur
.040 max
Phosphorus
.035 max
Molybdenum
.15/.25
Nickel
.40/.70
Chromium
.40/.60
Silicon
.15/.35
Manganese
.70/.90
Temp. °F
Normalizing
1650-1750
Annealing 1550-1600
Carburizing 1650-1700
Tempering 300-450
Mechanical Properties
Tensile Strength 85 ksi
Yield Point 65 ksi
Elongation 2" % 18-25
Red. Area % 55-65
Hardness Brinell 165-200
Hardness Rb 85-93
Machinability % 55














E52100 Alloy Steel

This bearing quality, high carbon, high chromium alloy can attain high hardness with excellent resistance to wear and abrasion. Applications include: cam rollers, shear and cutting blades, punches, bearings.

Typical Analysis:

Carbon
.95/1.10
Sulfur
.025 max
Phosphorus
.025 max
Chromium
1.30/1.60
Silicon
.15/.35
Manganese
.25/.45
Temp. °F
Normalizing
no
Annealing 1350-1450
Hardening 1500-1600
Tempering 350-450
Mechanical Properties
Tensile Strength 100-120 ksi
Yield Point 80-90 ksi
Elongation 2" % 12-22
Red. Area % 50-60
Hardness Brinell 200-220
Hardness Rb 93-100
Machinability % 40














e.t.d. 150 Alloy Steel

Similar in composition to 4140, e.t.d. 150 is produced by the Elevated Temperature Drawing process patented by the La Salle Steel Co. This process results in a bar that is stress-free and a minimum of 32 Rockwell C hardness, eleminating the need for further heat treating methods. When higher hardness is desired, a level of 57-60 Rockwell C is attainable by quenching and tempering. Along with their high strength, these bars have excellent machining characteristics. Uses include: axles, shafts, gears, pinions, fasteners.

Typical Analysis:

Carbon
.95/1.10
Sulfur
.025 max
Phosphorus
.025 max
Chromium
1.30/1.60
Silicon
.15/.35
Manganese
.25/.45
Mechanical Properties
Tensile Strength 150 ksi min
Yield Point 130 ksi min
Elongation 2" % 10-30
Red. Area % 35-45
Hardness Brinell 302 min
Hardness Rc 32 min
Machinability % 75