1.7734 (15CDV6) Tube — High-Strength Low-Alloy Seamless Steel Tube for Crankshafts
Material
1.7734 (15CDV6) is a low-carbon Cr-Mo-V high-strength low-alloy steel widely selected when crankshaft and rotating parts need a strong strength-to-weight balance, high fatigue capability, and reliable toughness. It is commonly referenced in aerospace and motorsport supply chains and is well known for being weldable compared with many other high-strength alloy steels.
Specifications
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Product form: Seamless round steel tube (hot-finished and/or cold-drawn; heat treatment per requirement).
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Typical supply length: 1–7 meters; custom cut available.
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Straightness (typical): 0.3–2 mm/m (by supply class).
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Delivery condition (common): Annealed / normalized / quenched & tempered (Q&T) to target strength level.
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Inspection (typical options): Dimensional check, chemical analysis, tensile/impact testing, and NDT such as UT/ET upon request (based on project requirement).
Key Features
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High yield & tensile strength with toughness (strength level adjustable via heat treatment).
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Good weldability profile for a high-strength steel (especially compared with many Cr-Mo grades that require stricter welding controls).
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Cr-Mo-V alloying supports fatigue-critical parts such as shafts and crankshafts, with stable properties after Q&T.
Our Advantages
1) “Can it be welded safely without losing properties or cracking?”
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15CDV6 is widely described as readily weldable with minimal property loss and typically without mandatory post-weld heat treatment in many practical applications.
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For comparison, common Cr-Mo steels like 4140 often require strict preheat/controlled procedures and are frequently discouraged for welding in the hardened & tempered condition. We provide fabrication guidance and can supply in a fabrication-friendly condition if welding is part of your process route.
2) “What strength level should I specify for crankshaft fatigue life?”
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We support Q&T strength targets by diameter/thickness and can align supply to your machining + final heat-treat plan (rough-machining first, then finish Q&T, or supply Q&T directly). Typical published strength windows are shown in the mechanical table below.
3) “Do you control toughness/impact performance?”
4) “Will machinability and dimensional stability be OK for crankshaft machining?”
5) “How do I confirm equivalence across standards and avoid a wrong substitute?”
Chemical Composition
| Grade |
Standard system (typical reference) |
C |
Si |
Mn |
Cr |
Mo |
V |
P |
S |
| 15CDV6 (1.7734) |
AIR 9160C (commonly referenced) |
0.12–0.18 |
≤0.20 |
0.80–1.10 |
1.25–1.50 |
0.80–1.00 |
0.20–0.30 |
≤0.020 |
≤0.015 |
| 42CrMo4 (1.7225) |
DIN EN ISO 683-2 / EN family |
0.38–0.45 |
0.10–0.40 |
0.60–0.90 |
0.90–1.20 |
0.15–0.30 |
— |
≤0.025 |
≤0.035 |
| AISI 4140 |
ASTM A29 (commonly referenced) |
0.36–0.44 |
0.10–0.40 |
0.65–1.10 |
0.75–1.20 |
0.15–0.35 |
— |
≤0.04 |
≤0.04 |
| SCM435 |
JIS G4053 |
0.33–0.38 |
0.15–0.35 |
0.60–0.90 |
0.90–1.20 |
0.15–0.30 |
— |
≤0.03 |
≤0.03 |
| 30KhGSA (30ХГСА) |
GOST 4543 (commonly referenced) |
0.28–0.34 |
0.90–1.20 |
0.80–1.10 |
0.80–1.10 |
— |
— |
≤0.025 |
≤0.025 |
Data compiled from published grade references/datasheets.
Mechanical Properties
Note: Mechanical properties vary with section size and heat treatment. Values below reflect commonly published Q&T / treated conditions.
| Grade |
Condition basis (example) |
Yield / Proof (MPa) |
Tensile (MPa) |
Elongation (%) |
Impact (example) |
| 15CDV6 (1.7734) |
Treated Ø16–40 mm (example) |
≥930 |
1080–1280 |
≥10 |
— |
| 42CrMo4 (1.7225) |
Q&T, round 16–40 mm |
≥750 |
1000–1200 |
≥11 |
≥35 J (Charpy-V) |
| AISI 4140 |
Heat-treated condition “T” (example table) |
≥665 (0.2% proof) |
850–1000 |
≥13 |
≥50 J (Charpy) |
| SCM435 |
Reported minimum values (example) |
≥835 |
≥985 |
≥12 |
≥63 J (Akv) |
| 30KhGSA (30ХГСА) |
Q&T example (Ø25 bar listing) |
830 |
1080 |
10 |
490 kJ/m² (KCU) |
Data compiled from published grade references/datasheets.
Standards & Compliance
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ASTM (typical references for similar alloy tubes/chemistry):
ASTM A519 (seamless mechanical tubing); ASTM A29/A29M (chemistry reference for 41xx families, e.g., 4140).
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EN (common routes for mechanical tubes & Q&T alloy steels):
EN/ISO 683-2 (Q&T alloy steels; includes 42CrMo4); project-specific tube supply often aligns with EN seamless tube standards depending on end use.
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GOST:
GOST 4543 (alloy structural steels); GOST 8731 / GOST 8733 (seamless tube references shown in grade listings).
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JIS:
JIS G4053 (SCM series alloy steels for machine structural use).
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GB (China):
Common equivalents for the Cr-Mo family include GB/T 3077 (42CrMo) (often cross-referenced with 42CrMo4 / 4140).
Application Fields
Broad industries: automotive & motorsport driveline parts, aerospace structures, heavy machinery, energy equipment.
Where it’s used inside the crankshaft value chain:
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Crankshaft body/blank machining: high-strength tube/stock for weight reduction concepts or specialized designs.
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Related rotating components: connecting rods, shafts, axles, gear/drive elements—especially where fatigue resistance and Q&T strength stability are critical.
Q: Are you trading company or manufacturer ?
A: manufacturer,also can do trading.
Q: How long is your delivery time?
A: Generally speaking,it is 10-15 days if the goods are in stock,or it is 30-40 days if the goods are not in stock,
it is according to quantity.
Q: Do you provide samples? is it free or extra ?
A: Yes, we could offer the sample for free charge but need pay the cost of freight.
Q: What is your terms of payment ?
A: Payment<=2000USD, 100% in advance. Payment>=2000USD, 30% T/T in advance ,balance before shippment.
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