Tubewell Steel & Engg. Co. is a leading manufacturer and stockist specializing in Alloy Steel Pipes, Tubes, Fittings and Flanges for critical industrial applications.
Weldable 0.30% carbon chromium-molybdenum "chromoly" bars with an excellent strength-to-weight ratio for oil & gas, aerospace and structural components.
Tubewell Steel & Engg. Co. stocks and supplies AISI 4130 round bars in Mumbai, India. Known internationally as 25CrMo4 and SCM430, 4130 combines good strength and toughness with far better weldability than higher-carbon grades, making it a favourite for wellhead equipment, aircraft parts and fabricated high-strength structures.
Strength, toughness and weldability in one chrome-moly grade
AISI 4130 is a low-alloy steel with nominally 0.30% carbon, 1% chromium and 0.20% molybdenum. The moderate carbon level keeps the heat-affected zone tougher and less crack-sensitive than in 4140, so 4130 can be welded by TIG, MIG and SMAW processes with suitable pre-heat. At the same time its chrome-moly chemistry provides good hardenability, allowing bars to be normalized or quenched and tempered to a wide range of strength levels.
In the oil and gas industry, 4130 bars and forgings are widely used for wellhead and christmas-tree components, where they are quenched and tempered to controlled hardness of 22 HRC max for sour service per NACE MR0175 / ISO 15156. We supply 4130 round bars hot rolled, forged, peeled or bright, in annealed, normalized or Q&T condition, ultrasonically tested on request and backed by EN 10204 3.1 certificates.
Standard supply range for AISI 4130 round bars
| Parameter | Details |
|---|---|
| Standards | ASTM A29 / A29M, ASTM A322, ASTM A331, ASTM A434, SAE J404, AMS 6370, EN 10083-3 |
| Grade | AISI / SAE 4130 (UNS G41300), 25CrMo4 (1.7218) |
| Diameter | 10 mm to 300 mm |
| Forms | Round Bar, Square Bar, Hex Bar, Flat Bar, Forged Blocks, Rings |
| Production | Hot Rolled, Forged, Cold Drawn |
| Length | 3 m to 6 m random, or saw cut to required length |
| Supply Condition | Annealed, Normalized, Normalized & Tempered, Quenched & Tempered |
| Sour Service | NACE MR0175 / ISO 15156 – 22 HRC max on request |
| Surface Finish | Black, Peeled, Rough Turned, Bright, Centreless Ground |
| Tolerance | As per ASTM A29; h9 / h10 / h11 for bright bars |
| 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 4130
| Grade | UNS | EN | W.Nr. | JIS | AFNOR |
|---|---|---|---|---|---|
| AISI 4130 | G41300 | 25CrMo4 | 1.7218 | SCM430 | 25CD4 |
Weight %, as per ASTM A29 / SAE J404
| Grade | C | Mn | P | S | Si | Cr | Mo |
|---|---|---|---|---|---|---|---|
| AISI 4130 | 0.28 – 0.33 | 0.40 – 0.60 | 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 | Hardness |
|---|---|---|---|---|
| Annealed | 560 MPa (81 ksi) | 460 MPa (67 ksi) | 21.5% | 217 HB max |
| Normalized | 670 MPa (97 ksi) | 435 MPa (63 ksi) | 25.5% | 197 HB |
| Q&T – 80K (NACE) | 655 MPa (95 ksi) min | 550 MPa (80 ksi) min | 18% min | 197 – 237 HB (22 HRC max) |
Typical values (for reference)
| Property | Metric | Imperial |
|---|---|---|
| Density | 7.85 g/cm³ | 0.284 lb/in³ |
| Melting Point (approx.) | 1432 °C | 2610 °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 | 42.7 W/m·K | 24.7 BTU/h·ft·°F |
| Mean Thermal Expansion (0–100°C) | 12.2 µm/m·°C | 6.8 µin/in·°F |
| Specific Heat | 0.477 J/g·°C | 0.114 BTU/lb·°F |
Theoretical weight of 4130 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 4130 round bars are used
Valve bodies, bonnets, hangers and christmas-tree components.
Engine mounts, landing gear parts and structural fittings.
Roll cages, suspension links and chassis components.
Cylinder heads, rod ends, manifolds and high-pressure fittings.
Shafts, spindles, couplings and welded machine frames.
Ordnance components and high-strength welded assemblies.
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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