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Pennsylvania Steel
4320 Alloy Steel Bar Alternative

Superior Steel Alternative to

SAE 4120 Steel

Pennsylvania Steel Corporation offers an alternative to AISI 4120 alloy steel.

We produce FLEXOR® steel to provide similar, if not superior, chemical and mechanical properties to 4120 alloy steel. These properties allow FLEXOR® steel to be used effectively for applications that require an excellent strength to weight ratio coupled with high strength, hardness and wear resistance as an alternative to 4120 steel. These include Structural Tubing, Frames, Gears, Piston Pins, Crankshafts, Clutch and Flywheel Components used as Aircraft, Aerospace and Automotive Components. Being a proprietary grade, Pennsylvania Steel insures that all FLEXOR® heats meet a high quality vacuum degas electric arc furnace melt process in order to insure cleanliness, grain refinement and maximum reduction ratios.

FLEXOR®'s dependable quality and adaptability in heat treatment allows for a wide range of physical properties that are more appealing than those of typical ASTM, AISI or SAE 4120 alloy steel. FLEXOR® has a higher core hardness, resulting in a more uniform hardness through any cross section. The more uniform hardness and a fine grain microstructure produce a steel that is low weight with high fatigue and tensile strength and is an excellent material for applications that require a lighter weight component with the strength of steel.

FLEXOR® steel is available in a variety of sizes and conditions. These include, but are not limited to, decarb free alloys, hot rolled rounds, peeled steel bars, ground and polished rounds, hot rolled flats, hot rolled plates, turned forged round and billet.

Contact Pennsylvania Steel Corporation today to learn more about FLEXOR® and its advantages over 4120 alloy steel.

SAE 4120 Steel Chemistry Composition vs. FLEXOR®:


  Carbon, C Manganese, Mn Phosphorous, P Sulfur, S Silicon, Si Chromium, Cr Molybdenum, Mo Tungsten, W
4120 .18-.23 .40-.60 .035(max) .04(max) .15-.35 .80-1.10 .15-.25 -
FLEXOR .32-.36 .60-.80 .025(max) .025(max) .15-.30 .75-1.00 .40-.60 .40-.70

Typical FLEXOR® Mechanical Properties (Based upon 1.00" dia.)

Mechanical Properties 30 HRC 40 HRC 45 HRC
UTS(ksi) Per ASTM E8-04 147 183 225
YS 0.2% offset Per ASTM E8-04 134 171 205
V-Notch Charpy Impact Per ASTM E23-06 80 45 21
RA% Per ASTM E8-04 64 60 50
Elongation Per ASTME E8-04 21 18 12
Poisson's Ratio per ASTM E111-04 .282
Young's Modulus per ASTM E111 30900 (ksi)

Contact one of our sales representatives today
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or call us today at 1-866-935-3967


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