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AISI/SAE 4140 Alloy Steel Round Bars

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AISI & SAE 4140 Round Bars Suppliers

AISI/SAE 4140 Alloy Steel Round Bars

Sachin Steel Center manufactures and supplies premium AISI/SAE 4130 alloy steel round bars, engineered for demanding industrial and engineering applications. Made from a balanced chromium-molybdenum alloy, our 4130 bars combine high strength, excellent toughness and reliable heat-treatment response while retaining good machinability and weldability—making them suitable for both structural and high-performance components. Produced using controlled forging and rolling processes, the bars are available in standard and custom diameters and lengths, and can be supplied in annealed, normalized or heat-treated conditions to match application requirements. Key material characteristics include enhanced tensile strength, improved fatigue resistance, good hardenability, and resistance to wear and oxidation under elevated temperatures thanks to chromium and molybdenum additions.

Typical applications for AISI/SAE 4130 round bars include aerospace components, crankshafts, axles, gears, hydraulic parts, structural fittings and general engineering spares where a high strength-to-weight ratio and dependable performance are required. Each batch undergoes stringent quality checks—chemical analysis, mechanical testing, hardness checks and mill test certificates are provided on request to ensure traceability and compliance with national and international specifications.

For technical guidance, custom sizes or pricing, contact Sachin Steel Center for datasheets, test reports and fast quotations.

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Table Of Content

Introduction To SAE/AISI 4140 Round Bars

SAE/AISI 4140 is a chromium-molybdenum (Cr-Mo) low-alloy steel supplied as round, hex, square and flat bars for demanding industrial uses. It is valued for its high tensile and yield strength, excellent toughness and good fatigue resistance. 4140 responds well to heat treatment (annealing, normalizing, quench & temper) and accepts surface hardening processes such as induction, flame hardening and nitriding to improve wear life. Typical applications include axles, shafts, spindles, gears, hydraulic components, fasteners and tooling where dimensional stability and durability are essential. The alloy is offered in a wide range of diameters (commonly 4–350 mm) and is supplied with standard tests and mill certificates on request.

Key characteristics:

  • High strength and hardenability (tunable by heat treatment)
  • Good toughness and fatigue resistance under cyclic loading
  • Good machinability in annealed condition
  • Compatible with surface hardening (induction/flame, nitriding)
  • Fair weldability — preheat/post-weld heat treatment often advised for heat-treated material
  • Common tensile/yield ranges depend on temper (typical yield ≈ 80 ksi; tensile ≈ 100 ksi+ in heat-treated conditions)
  • Supplied to ASTM/ASME/AISI/SAE standards with testing and traceability available

Types of 4140 Alloy Steel Round Bar

Hex Bar

SAE 4140 Hex Bar

Bright Bar

AISI 4140 Bright Bar

hollow bar

AISI 4140 Hollow Bar

Square Bar

SAE 4140 Square Bar

Polished Bar

AISI 4140 Forged Bar

Flat Bar

SAE 4140 Flat Bar

Request Quote on Alloy AISI 4140 Round Bars
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Manufacturer of SAE 4140 Rod, ASTM AISI AS 4140 Bright Bar Supplier, AISI 4140 Flat Bar, AISI 4140 Steel Bars, 4140 Alloy Steel Cold Rolled Bars, UNS G41400 Round bars, AISI 4140 Tthreaded Rods, 42crmo4 hollow bars.

Specification List of 4140 Round Bar

Sizes 2-100mm A/F
Tolerance H9, H8, H10, K12, H13K9, K10, H11, H12, K11
Supplier of Round bar in Sizes Diameter: 3-~800mm
Technique Hot Rolled, Cold Drawn, Cold Rolled, Forged, Rod
Processing Bar cutting to 650mm
Surface Bright, Hot Rolled Pickled, Sand Blasting Finished, Hairline, Cold Drawn, Polished
Condition Hardened and tempered, annealed
Form Supplier in Precision Square, Ingot, T-Bar, Rod, Round, Welding Rod, I/H Bar, Flat Bar, Blocks, Rings, Rectangle, Hex (A/F), Hollow, Threaded, Profiles, Ground Bar, Channel Bar, Billet, Triangle, Round Rod, Half Round Bar, Forging etc.
Square bar Sizes 4 to 100mm
Finish Grinding, centreless ground, Cold (bright) drawn, smooth turned, peeled, slit rolled edge, hot rolled, hot rolled annealed, Bright, Polish, Rough Turned, Centreless Ground & Black
Flat bar Sizes Thickness: 2 -100mm
Width: 10 to 500mm

Chemical Composition of AISI/SAE 4140 Round Bars

Element Content (%)
Iron (Fe) 96.8 to 97.8
Chromium (Cr) 0.8 to 1.1
Manganese (Mn) 0.75 to 1.0
Carbon (C) 0.38 to 0.43
Silicon (Si) 0.15 to 0.35
Molybdenum (Mo) 0.15 to 0.25
Sulfur (S) 0 to 0.040
Phosphorus (P) 0 to 0.035

AISI 4140 Equivalent Materials for Rods

STANDARD UNS WERKSTOFF NR.
AISI 4140 G41400 1.7225

Dimensions Standards for Alloy Steel 4140 Round Bars

Diameter or
Width
(mm)		 Weight per meter Sectional Area Perimeter
Square
(kg)		 Round
(kg)		 Square
(cm²)		 Round
(cm²)		 Square
(cm)		 Round
(cm)
5.0 0.20 0.15 0.25 0.20 2.0 1.57
5.5 0.24 0.19 0.30 0.24 2.2 1.78
6.0 0.28 0.22 0.36 0.28 2.4 1.88
7.0 0.38 0.30 0.49 0.38 2.8 2.20
8.0 0.50 0.39 0.64 0.50 3.2 2.51
9.0 0.64 0.50 0.81 0.64 3.6 2.83
10 0.73 0.63 1.00 0.79 4.0 3.14
11 0.95 0.75 1.21 0.95 4.4 3.46
12 1.13 0.89 1.44 1.13 4.8 3.77
14 1.54 1.21 1.96 1.54 5.6 4.40
16 2.01 1.58 2.56 2.01 6.4 5.03
18 2.54 2.00 3.24 2.54 7.2 5.65
20 3.14 2.47 4.00 3.14 8.0 6.28
22 3.80 2.98 4.84 3.80 8.8 6.91
25 4.91 3.85 6.25 4.91 10.0 7.85
28 6.15 4.83 7.84 6.16 11.2 8.80
32 8.04 6.31 10.24 8.04 12.8 10.05
36 10.17 7.99 12.96 10.18 14.4 11.31
40 12.56 9.86 16.00 12.57 16.0 12.57
45 15.90 12.49 20.25 15.90 18.0 14.14
50 19.62 15.41 25.00 19.64 20.0 15.71
56 24.62 19.34 31.36 24.63 22.4 17.59
63 31.16 24.47 36.69 31.17 25.2 19.79
71 39.57 31.08 50.41 39.59 28.4 22.31
80 50.24 39.46 64.00 50.27 32.0 25.13

Alloy Steel Round Bar AISI/SAE 4140 Mechanical Properties

Grade Tensile Strength (MPa) min Yield Strength 0.2% Proof (MPa) min Elongation (% in 50mm) min
AISI 4140 930 735 12

Thermal Properties of SAE 4140 Hex Bar

Latent Heat of Fusion 250 J/g
Maximum Temperature 420 °C (790 °F)
Melting Completion 1460 °C (2660 °F)
Melting Onset 1420 °C (2580 °F)
Specific Heat Capacity 470 J/kg-K (0.11 BTU/lb-°F)
Thermal Conductivity 43 W/m-K (25 BTU/h-ft-°F)
Thermal Expansion 13 µm/m-K

Alloy Steel F1 A182 Round Bars & Rods Updated Price List

Get the latest Alloy Steel A182 F1 Round Bars price list from Sachin Steel. Click on the Request a Quote button or contact us for updated prices, stock details, and specifications. We maintain a ready inventory of standard sizes to ensure quick delivery. Offering high-quality products at competitive prices, Sachin Steel is your trusted source for Alloy Steel A182 F1 Round Bars & Rods worldwide.

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Sizes Chart for AISI/SAE 4140 Round Bars

US Bar Metric Japanese Canadian/ASTM
Diameter(Inch) Alloy Steel 4140 Bar Size Diameter (millimeter) Alloy Steel 4140 Bar Size Diameter (millimeter) Alloy Steel 4140 Bar Size Diameter (millimeter2) Alloy Steel 4140 Bar Size
0.250 #2 5 5 6 6 100 10M
0.375 #3 5.5 5.5 10 10 200 15M
0.500 #4 6 6 13 13 300 20M
0.625 #5 7 7 16 16 500 25M
0.750 #6 8 8 19 19 700 30M
0.875 #7 9 9 22 22 1000 35M
1.000 #8 10 10 25 25 1500 45M
1.125 #9 11 11 29 29 2500 55M
1.250 #10 12 12 32 32
1.375 #11 14 14 35 35
1.500 #12 16 16 38 38
1.625 #13 18 18 41 41
1.750 #14 20 20 44 44
1.875 #15 22 22 48 48
2.000 #16 25 25 51 51
2.250 #18 28 28 57 57
32 32
36 36
40 40
44 44
50 50

AISI/SAE 4140 Round Bar Weight Chart

Alloy Steel 4140 Bar Size kilogram / Meter kilogram / Foot Size kilogram / Meter kilogram / Foot Size kilogram / Meter kilogram / Foot
1/8″ 0.062 0.019 22 millimeter 2.979 0.908 3 to 1/4″ 41.996 12.800
3 millimeter 0.055 0.017 20 millimeter 2.470 0.753 3″ 35.762 10.900
4 millimeter 0.098 0.030 24 millimeter 3.543 1.080 3 to 3/4″ 55.780 17.001
5/32″ 0.095 0.029 7/8″ 3.038 0.926 3 to 1/2″ 48.772 14.850
5 millimeter 0.154 0.047 1″ 3.970 1.210 4 to 1/4″ 72.249 21.908
3/16″ 0.141 0.043 25 millimeter 3.871 1.180 4″ 63.340 19.306
6 millimeter 0.223 0.068 27 millimeter 4.490 1.368 4 to 3/4″ 90.249 27.366
7/32″ 0.190 0.058 26 millimeter 4.170 1.271 4 to 1/2″ 80.340 24.4487
7 millimeter 0.298 0.091 30 millimeter 5.548 1.691 5 to 1/2″ 121.000 36.690
1/4″ 0.249 0.076 1 to 1/8″ 5.033 1.534 5″ 99.940 30.461
8 millimeter 0.398 0.120 32 millimeter 6.314 1.894 6 to 1/2″ 167.630 51.093
5/16″ 0.387 0.118 1 to 1/4″ 6.349 1.924 6″ 143.900 43.860
3/8″ 0.557 0.170 35 millimeter 7.553 2.390 7 to 1/2″ 225.000 68.226
9 millimeter 0.498 0.152 1 to 3/8″ 7.550 2.303 7″ 196.000 59.432
11 millimeter 0.748 0.228 38 millimeter 8.903 2.792 10″ 397.140 121.048
10 millimeter 0.620 0.189 36 millimeter 7.999 2.438 8″ 254.55 77.586
12 millimeter 0.889 0.271 40 millimeter 9.872 3.009
7/16″ 0.761 0.232 1 to 1/2″ 8.951 2.715
13 millimeter 1.043 0.318 1 to 3/4″ 12.179 3.712
1/2″ 0.994 0.303 1 to 5/8″ 10.449 3.200
9/16″ 1.256 0.383 1 to 7/8″ 13.977 4.260
14 millimeter 1.207 0.368 45 millimeter 12.555 3.807
5/8″ 1.551 0.473 50 millimeter 15.414 4.698
15 millimeter 1.391 0.424 48 millimeter 14.205 4.330
17 millimeter 1.791 0.543 2 to 1/8″ 17.963 5.475
16 millimeter 1.578 0.481 2″ 15.906 4.848
18 millimeter 2.001 0.610 60 millimeter 22.205 6.768
11/16″ 1.880 0.573 2 to 1/4″ 20.128 6.135
3/4″ 2.237 0.682 2 to 3/8″ 22.435 6.838
2 to 1/2″ 24.856 7.576
2 to 5/8″ 27.409 8.354
2 to 3/4″ 30.083 9.169

4140 Alloy Steel Round Bar Uses

    • Petrochemical Industry
    • Chemical Industry
    • Oil and Gas Industry
    • Pulp & Paper Indusry
    • Power Plant Industry
    • Food Processing Industry
    • Pharmaceuticals Industry
    • Energy Industry
    • Aerospace Industry
Application Industries

Frequently Asked Questions About AISI/SAE 4140 Alloy Steel Round Bars

Alloy Steel 4140 Round Bar is a chromium-molybdenum medium carbon steel known for high strength, toughness, and wear resistance. It is widely used in industrial and mechanical applications requiring durability under high stress.

These bars are used in crankshafts, axles, gears, spindles, bolts, hydraulic shafts, tool holders, and other heavy-duty machine components.

Yes, they can be quenched and tempered to achieve the desired hardness, strength, and wear resistance, depending on the application.

Yes, but preheating and post-weld heat treatment are recommended to avoid cracking due to its alloy composition.

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