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4140
Qilu
Product Description
Hot forged, hot rolled and cold drawn round bar supplied in QT (quenched & tempered) condition, 20 mm to 600 mm diameter, with heat treatment and rough machining done in our own workshop.
Equivalent to: AISI / SAE 4140 · DIN 42CrMo4 (1.7225) · JIS SCM440 · BS EN19 / 708M40 · GB 42CrMo
Supply form: Round bar
Process: Hot forged / hot rolled / cold drawn
Condition: QT (quenched & tempered) or annealed
Diameter range: 20–600 mm
Melting route: EAF + LF + VD
Certificate: EN 10204 3.1 standard, 3.2 on request
Lead time: 15–30 days depending on size and heat treatment
4140 is a chromium-molybdenum low alloy steel specified in ASTM A29 and SAE J404. The combination of Cr and Mo gives it good hardenability and resistance to tempering, which is why it stays strong at larger cross-sections where plain carbon steels soften out.
| Element | AISI 4140 (%) | DIN 42CrMo4 / 1.7225 (%) |
|---|---|---|
| Carbon (C) | 0.38 – 0.43 | 0.38 – 0.45 |
| Manganese (Mn) | 0.75 – 1.00 | 0.60 – 0.90 |
| Silicon (Si) | 0.15 – 0.35 | ≤ 0.40 |
| Chromium (Cr) | 0.80 – 1.10 | 0.90 – 1.20 |
| Molybdenum (Mo) | 0.15 – 0.25 | 0.15 – 0.30 |
| Phosphorus (P) | ≤ 0.035 | ≤ 0.025 |
| Sulphur (S) | ≤ 0.040 | ≤ 0.035 |
Note: Values above are standard specification ranges for reference. The actual heat analysis of every shipment is reported on the EN 10204 3.1 certificate we issue with your order.
Properties below are typical achievable values after austenitising at 840–860 °C, oil quenching and tempering. Mechanical strength varies noticeably with section size — the larger the bar, the lower the attainable core hardness — so always specify your working diameter when ordering.
| Diameter | Yield Rp0.2 min | Tensile Rm | Elongation A min | Impact KV (RT) | Hardness |
|---|---|---|---|---|---|
| ≤ 16 mm | 900 MPa | 1100 – 1300 MPa | 10 % | ≥ 30 J | 32 – 38 HRC |
| 16 – 40 mm | 750 MPa | 1000 – 1200 MPa | 11 % | ≥ 35 J | 30 – 36 HRC |
| 40 – 100 mm | 650 MPa | 900 – 1100 MPa | 12 % | ≥ 40 J | 28 – 34 HRC |
| 100 – 160 mm | 600 MPa | 850 – 1000 MPa | 13 % | ≥ 45 J | 26 – 32 HRC |
| 160 – 250 mm | 550 MPa | 800 – 950 MPa | 13 % | ≥ 45 J | 24 – 30 HRC |
Note: Please verify the final figures against your mill's routine production data before publishing. Publish what you can hit consistently, not the best batch you ever shipped.
Use this table to select the tempering window for the hardness your application needs. Higher tempering temperature trades hardness for toughness.
| Tempering Temperature | Approx. Hardness (HRC) | Typical Use |
|---|---|---|
| 200 °C | 52 – 55 | Wear parts, cold work tooling |
| 300 °C | 46 – 49 | High strength pins, springs |
| 400 °C | 40 – 43 | Gears, shafts under high load |
| 500 °C | 33 – 36 | General machinery shafts |
| 550 °C | 30 – 33 | Hydraulic rods, connecting rods |
| 600 °C | 27 – 30 | Structural parts needing toughness |
| 650 °C | 24 – 27 | Maximum toughness applications |
One of the most common questions we get is which standard is interchangeable with which. Matching on grade name alone is risky — small differences in Mn and Cr ranges affect hardening response, so always compare the actual composition before substituting.
| Standard | Designation | Region |
|---|---|---|
| AISI / SAE | 4140 (UNS G41400) | USA |
| DIN / W-Nr | 42CrMo4 / 1.7225 | Germany |
| EN | 42CrMo4 (EN 10083-3) | Europe |
| JIS | SCM440 (G4053) | Japan |
| BS 970 | EN19 / 708M40 | United Kingdom |
| GB / YB | 42CrMo (GB/T 3077) | China |
| ISO | 42CrMo4 | International |
4140 sits in a sweet spot: stronger and more hardenable than 1045, considerably cheaper than nickel-bearing grades like 4340. That balance explains why it shows up across so many industries.
Gears, gear shafts and pinions for heavy equipment
Crankshafts, connecting rods and camshafts
Hydraulic cylinder rods and piston rods
Oil & gas drill collars, tool joints and subs
Bolts, studs and high-tensile fasteners
Axles, spindles and rolls for rolling mills
Plastic mould frames and die holder blocks
Most suppliers in this business are traders who subcontract everything. We run our own processes, which means shorter cycles and one point of accountability when something needs fixing.
Heat treatment shop — quenching and tempering to your target hardness, with furnace charts recorded per batch
Machining shop — rough turning, peeling and cutting to length, so your bar arrives ready for finish machining
Testing — ultrasonic per ASTM A388 / EN 10228-3, hardness mapping across the section, tensile and impact testing
Certification — EN 10204 3.1 as standard, 3.2 available with third-party witness (ABS, BV, CCS, GL)
Export packing — bundled, end-capped and rust-protected for sea freight
Hot forged round bar from 20 mm up to 600 mm. For sizes below 80 mm we can also offer hot rolled and cold drawn, which gives you a better surface finish and tighter tolerance than forged material.
They are treated as equivalent in most applications, but they are not identical. The DIN grade allows a slightly wider carbon range and higher chromium content. If you are replacing one with the other, compare the actual composition tables above — the difference matters for hardening response on large sections.
Yes. We quench and temper to order and verify hardness on multiple points across the bar section. Tell us the required hardness range and the working diameter together, because achievable core hardness depends on section size.
EN 10204 3.1 mill certificate is included as standard, showing full heat analysis and mechanical test results. If you need 3.2 certification we arrange third-party inspection with ABS, BV, CCS or GL.
For standard sizes held in stock we accept trial quantities. For forged-to-order sizes the MOQ depends on the melting batch — contact us with your specification and we will confirm.
15 to 30 days depending on size and heat treatment requirements, plus sea freight. We ship regularly to South America, Australia and Europe.
Send us your diameter, length, quantity, required hardness and destination port. You will get a quotation with the full technical proposal within 24 hours.
Contact us: enquiry@qilumetal.com
