40Cr 5140
Qilu
7228400000
Product Description
Hot forged and rolled 40Cr / 5140 round bar supplied annealed or QT, 10 mm to 400 mm diameter, with heat treatment and rough machining done in our own workshop.
Equivalent to: GB 40Cr · AISI / SAE 5140 · DIN 41Cr4 (1.7035) · JIS SCr440 · BS 530A40
40Cr 5140 SCr440 1.7035 41Cr4 Alloy Forged Steel Bar
40Cr 5140 SCr440 1.7035 41Cr4 Alloy Forged Steel Bar
40Cr 5140 SCr440 1.7035 41Cr4 Alloy Forged Steel Bar
Supply form — Round bar, flats, forgings
Process — Hot forged / hot rolled
Condition — Annealed, or QT to 241–302 HB
Diameter range — 10–400 mm
Standard — GB/T 3077 · ASTM A29 · DIN EN 10083-3
Certificate — EN 10204 3.1 standard, 3.2 on request
Lead time — 15–30 days
40Cr (AISI 5140 / DIN 41Cr4) is the most common chromium alloy structural steel in China, specified in GB/T 3077. With 0.37–0.44 % carbon and 0.80–1.10 % chromium, it reaches ~980 MPa tensile after quench-and-temper — the go-to grade for medium-stress gears, shafts and spindles in Chinese machinery.
| Element | C | Si | Mn | P (max) | S (max) | Cr | Cu (max) |
|---|---|---|---|---|---|---|---|
| GB/T 3077 | 0.37–0.44 | 0.17–0.37 | 0.50–0.80 | 0.035 | 0.035 | 0.80–1.10 | 0.25 |
Typical values for the QT condition at medium section.
| Property | Annealed | QT (typical) |
|---|---|---|
| Tensile strength, Rm (MPa) | ≤ 595 | 880–1080 |
| Yield strength, Re (MPa) | ≤ 375 | ≥ 640 |
| Elongation, A5 (%) | ≥ 19 | ≥ 9 |
| Impact, AKU2 (J) | ≥ 47 | ≥ 31 |
| Hardness (HB) | ≤ 207 | 241–302 |
| Standard | Designation |
|---|---|
| GB (China) | 40Cr |
| ASTM / SAE (USA) | 5140 |
| DIN / EN (Germany/Europe) | 41Cr4 / 1.7035 |
| JIS (Japan) | SCr440 |
| BS (UK) | 530A40 / 530M40 |
| ISO | 41Cr4 |
Machinery — gears, pinions, gear shafts, spindles
Automotive — crankshafts, axle shafts, connecting rods
Machine tools — spindles, lead screws, guide rods
General engineering — keys, couplings, levers, brackets
40Cr is oil-quenched from 840–860 °C and tempered between 520–680 °C depending on the strength required. It is the standard heat-treat grade for Chinese machinery and responds predictably — we set the tempering temperature by the OD and the spec on your drawing, and verify with hardness testing across the section.
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
They are the same family. Chemistry ranges are very close (0.37–0.44 % C, 0.80–1.10 % Cr) and they are used interchangeably in most machinery. If your drawing specifies one of them we can supply against either spec.
42CrMo4 adds ~0.20 % molybdenum, which lifts hardenability and toughness — used for higher-stress service. 40Cr / 41Cr4 is the economical choice for general machinery shafting. See our 4140 / 42CrMo4 page for the upgrade grade.
Yes. We supply to GB/T 3077 with mill certificate in Chinese or English per EN 10204 3.1, including heat analysis and mechanical test results. For third-party inspection we can arrange ABS / BV / CCS / GL.
Send us your diameter, length, quantity, required hardness and destination port. You will get a quotation with the full technical proposal within 24 hours.
Email: enquiry@qilumetal.com | Web: www.qilumetal.com
