1. Supply Range for AISI alloy 4140 steel bar

4140 Steel Round Bar: diameter 8mm – 3000mm
4140 Steel Plate: thickness 10mm – 1500mm x width 200mm – 3000mm
4140 Steel Grade Square: 20mm – 500mm
Surface Finish: Black, Rough Machined, Turned or as per given requirements.

2. Common 4140 Steel Specifications

Country	USA	German	British	Japan	China	Australia
Standard	ASTM A29	DIN 17200	BS 970	JIS G4105	GB/T 3077	AS 1444
Grades	4140	1.7225/ 42CrMo4	42CrMo4	SCM440	42CrMo	4140

3. 4140 Steel Bar Chemical Composition

Standard	Grade	C	Mn	P	S	Si	Cr	Mo
ASTM A29	4140	0.38-0.43	0.75-1.00	0.035	0.040	0.15-0.35	0.8-1.10	0.15-0.25
EN 10083/EN 10250	42CrMo4/1.7225	0.38-0.45	0.6-0.9	0.035	0.035	0.4	0.9-1.2	0.15-0.30
JIS G4105	SCM440	0.38-0.43	0.60-0.85	0.03	0.03	0.15-0.35	0.9-1.2	0.15-0.30

4. Mechanical Properties of AISI Alloy 4140 Steel Bar, Plates, Square

Properties	Metric	Imperial
Tensile strength	655 MPa	95000 psi
Yield strength	415 MPa	60200 psi
Bulk modulus (typical for steel)	140 GPa	20300 ksi
Shear modulus (typical for steel)	80 GPa	11600 ksi
Elastic modulus	190-210 GPa	27557-30458 ksi
Poisson’s ratio	0.27-0.30	0.27-0.30
Elongation at break (in 50 mm)	25.70%	25.70%
Hardness, Brinell	197	197
Hardness, Knoop (converted from Brinell hardness)	219	219
Hardness, Rockwell B (converted from Brinell hardness)	92	92
Hardness, Rockwell C (converted from Brinell hardness. Value below normal HRC range, for comparison purposes only)	13	13
Hardness, Vickers (converted from Brinell hardness)	207	207
Machinability (based on AISI 1212 as 100 machinability)	65	65

5. Forging

Preheat the steel carefully, heat to 1150 oC – 1200 oC maximum, hold until temperature is uniform throughout the section.
Do not forge below 850 oC.Following forging operation the work piece should be cooled as slowly as possible.

6. AISI 4140 Steel Grade Heat Treatment

• Annealing
  Heat ASTM 4140 steels to 800 oC – 850 oC, hold until temperature is uniform throughout the section and cool in furnace.
• Normalizing
  Heat steel alloy 4140 to 870 oC – 900 oC, hold until temperature is uniform throughout the section, soak for 10 – 15 minutes and cool in still air.
• Tempering
  Re-heat 4140 grade steel to 550 oC – 700 oC as required, hold until temperature is uniform throughout the section, soak for 1 hour per 25 mm of section, and cool in still air.

7. Hardening of AISI Alloy Steel 4140

AISI alloy 4140 steel bar, plate and square can be hardened by cold working, or heating and quenching.

SAE 4140 alloy steel is usually supplied ready heat treated to hardness in 18-22 HRC. If further heat treatment is required, then heat to 840 oC – 875 oC, hold until temperature is uniform throughout the section, soak for 10 – 15 minutes per 25 mm section, and quench in oil, water, or polymer as required.

8. Application of AISI alloy round 4140 steel bar

ASTM alloy 4140 steel bar, flat or plate material can be used for as wide variety of applications where greater toughness and wear resistance is needed over lower carbon grades. Typical applications for 4140 tool steel uses include Components, Adapters, Arbors,strippers, holder blocks, mold bases, ejectors, back up and support tooling, fixtures, jigs, molds, cams, drill collars, Axle Shafts, Bolts, Crankshafts,stubs, couplings, reamer bodies, axles, shafting, piston rods, rams, hydraulic machinery shafts, gears, sprockets, gear racks, chain links, spindles, tool bodies, tool holders, tie rods, Connection Rods, Chuck Bodies, Collets, Conveyor Pins & Rolls, Ejector Pins, Forks, Gears, Guide Rods, Hydraulic Shafts & Parts,Lathe Spindles, Logging Parts, Milling Spindles, Motor Shafts, Nuts, Pinch Bars, Pinions, Pump Shafts,boring bars,tracks, slides, wear strips or parts, forming dies, brake dies, trim dies, bolsters, machinery parts and components, etc.