Tubewell Steel & Engg. Co. is a leading manufacturer and stockist specializing in Alloy Steel Pipes, Tubes, Fittings and Flanges for critical industrial applications.
Medium-carbon chromium-molybdenum alloy steel bars with high strength, toughness and wear resistance for shafts, gears, bolting and oilfield components.
Tubewell Steel & Engg. Co. stocks and supplies AISI 4140 round bars in Mumbai, India. Also known as 42CrMo4 and SCM440, 4140 is a 0.40% carbon chrome-moly steel prized for its deep hardenability, high fatigue strength and good toughness after quenching and tempering – the go-to grade for highly stressed machined parts.
Why 4140 is the most versatile heat-treatable alloy bar
AISI 4140 is a low-alloy steel containing nominally 0.40% carbon, 1% chromium and 0.20% molybdenum. Chromium increases hardenability and wear resistance, while molybdenum improves depth of hardening, high-temperature strength and resistance to temper embrittlement. In the annealed condition 4140 machines readily; after oil quenching and tempering it develops an excellent combination of strength, ductility and impact toughness, and it responds well to flame, induction and nitride hardening for wear-resistant surfaces.
We supply 4140 round bars hot rolled, forged, peeled or bright, in annealed or pre-hardened & tempered condition (typically 28–32 HRC) as per ASTM A29, A322 and A434. Bars are ultrasonically tested on request, identified by heat number and accompanied by EN 10204 3.1 mill test certificates. Saw cutting to size and heat treatment to customer hardness ranges are offered for quick, ready-to-machine supply.
Standard supply range for AISI 4140 round bars
| Parameter | Details |
|---|---|
| Standards | ASTM A29 / A29M, ASTM A322, ASTM A331, ASTM A434, SAE J404, AMS 6382, EN 10083-3 |
| Grade | AISI / SAE 4140 (UNS G41400), 42CrMo4 (1.7225) |
| Diameter | 10 mm to 300 mm |
| Forms | Round Bar, Square Bar, Hex Bar, Flat Bar, Forged Blocks, Shafts |
| Production | Hot Rolled, Forged, Cold Drawn |
| Length | 3 m to 6 m random, or saw cut to required length |
| Supply Condition | Annealed, Normalized, Hardened & Tempered (pre-hardened 28–32 HRC) |
| Surface Finish | Black, Peeled, Rough Turned, Bright, Centreless Ground |
| Tolerance | As per ASTM A29; h9 / h10 / h11 for bright bars |
| Straightness | Max. 1 mm per metre (closer on request) |
| Ultrasonic Testing | SEP 1921, ASTM A388, EN 10228-3 |
| Testing | Chemical, Tensile, Hardness, Charpy Impact, Grain Size, Inclusion Rating |
| Certificates | EN 10204 3.1 / 3.2, TPI Reports |
International equivalents of AISI 4140
| Grade | UNS | EN | W.Nr. | JIS | BS 970 | AFNOR |
|---|---|---|---|---|---|---|
| AISI 4140 | G41400 | 42CrMo4 | 1.7225 | SCM440 | 708M40 / EN19 | 42CD4 |
Weight %, as per ASTM A29 / SAE J404
| Grade | C | Mn | P | S | Si | Cr | Mo |
|---|---|---|---|---|---|---|---|
| AISI 4140 | 0.38 – 0.43 | 0.75 – 1.00 | 0.035 max | 0.040 max | 0.15 – 0.35 | 0.80 – 1.10 | 0.15 – 0.25 |
Typical values at room temperature by condition
| Condition | Tensile Strength | Yield Strength (0.2%) | Elongation | Reduction of Area | Hardness |
|---|---|---|---|---|---|
| Annealed | 655 MPa (95 ksi) | 415 MPa (60 ksi) | 25.7% | 56.9% | 197 HB |
| Normalized | 1020 MPa (148 ksi) | 655 MPa (95 ksi) | 17.7% | 46.8% | 302 HB |
| Q&T (Pre-hardened) | 930 – 1080 MPa | 750 MPa min | 12% min | 45% min | 28 – 32 HRC |
Typical values (for reference)
| Property | Metric | Imperial |
|---|---|---|
| Density | 7.85 g/cm³ | 0.284 lb/in³ |
| Melting Point (approx.) | 1416 °C | 2580 °F |
| Modulus of Elasticity | 205 GPa | 29.7 × 10³ ksi |
| Shear Modulus | 80 GPa | 11.6 × 10³ ksi |
| Poisson's Ratio | 0.29 | 0.29 |
| Thermal Conductivity | 42.6 W/m·K | 24.6 BTU/h·ft·°F |
| Mean Thermal Expansion (0–100°C) | 12.2 µm/m·°C | 6.8 µin/in·°F |
| Specific Heat | 0.473 J/g·°C | 0.113 BTU/lb·°F |
Theoretical weight of 4140 round bars – weight (kg/m) = D² × 0.006165
| Diameter (mm) | Diameter (inch, approx.) | Weight (kg/m) | Weight per 6 m Bar (kg) |
|---|---|---|---|
| 10 | 0.39 | 0.62 | 3.70 |
| 12 | 0.47 | 0.89 | 5.33 |
| 16 | 0.63 | 1.58 | 9.47 |
| 20 | 0.79 | 2.47 | 14.80 |
| 25 | 0.98 | 3.85 | 23.12 |
| 30 | 1.18 | 5.55 | 33.29 |
| 32 | 1.26 | 6.31 | 37.88 |
| 36 | 1.42 | 7.99 | 47.94 |
| 40 | 1.57 | 9.86 | 59.18 |
| 45 | 1.77 | 12.48 | 74.90 |
| 50 | 1.97 | 15.41 | 92.48 |
| 55 | 2.17 | 18.65 | 111.89 |
| 60 | 2.36 | 22.19 | 133.16 |
| 65 | 2.56 | 26.05 | 156.28 |
| 70 | 2.76 | 30.21 | 181.25 |
| 75 | 2.95 | 34.68 | 208.07 |
| 80 | 3.15 | 39.46 | 236.74 |
| 90 | 3.54 | 49.94 | 299.62 |
| 100 | 3.94 | 61.65 | 369.90 |
| 110 | 4.33 | 74.60 | 447.58 |
| 120 | 4.72 | 88.78 | 532.66 |
| 130 | 5.12 | 104.19 | 625.13 |
| 140 | 5.51 | 120.83 | 725.00 |
| 150 | 5.91 | 138.71 | 832.28 |
| 160 | 6.30 | 157.82 | 946.94 |
| 180 | 7.09 | 199.75 | 1198.48 |
| 200 | 7.87 | 246.60 | 1479.60 |
| 220 | 8.66 | 298.39 | 1790.32 |
| 250 | 9.84 | 385.31 | 2311.88 |
| 280 | 11.02 | 483.34 | 2900.02 |
| 300 | 11.81 | 554.85 | 3329.10 |
Weights are theoretical, based on a density of 7.85 g/cm³ (D in mm). Actual weights may vary within mill tolerances and with surface finish.
Where AISI 4140 round bars are used
Drill collars, tool joints, kelly bars, subs and pump shafts.
Axle shafts, crankshafts, connecting rods and steering parts.
Pinions, gear shafts, spindles and couplings for gearboxes.
High-tensile studs and bolts (ASTM A193 B7 bar stock).
Piston rods, cylinder components and hydraulic fittings.
Wear-resistant pins, bushings and earth-moving parts.
Quality you can verify on every heat
Large inventory for fast dispatch
MTC EN 10204 3.1 / 3.2
Positive material identification
Pan-India & export shipping
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