1. Specifications & Capability
FUSHUN METAL forges rudder stocks and rudder pintles in 42CrMo4 (1.7225), AISI 5140 and martensitic stainless 1.4006 (410), 300-800 mm in diameter and up to 12 m long. Each part is quenched and tempered for strength and corrosion resistance, then machined with keyways, tapers and coupling flanges to shipyard drawings under classification society survey.
The plant holds factory approval from CCS, BV, DNV, GL, LR, KR and ABS, so every rudder stock is witnessed and certified at the stage the vessel’s class requires.
| Grade / Section (mm) | Rm (MPa) | Rp0.2 (MPa) | A (%) | KV (J) |
|---|---|---|---|---|
| 42CrMo4, up to 250 | 750-950 | 520 min | 14 | 27 min |
| AISI 5140, up to 250 | 800-950 | 620 min | 13 | 25 min |
| 1.4006, up to 160 | 650-850 | 450 min | 15 | 25 min |
| 300-800 | – | – | – | Per class rules |
Values follow EN 10250-3 and EN 10088-3; final acceptance follows the applicable classification society rules with test coupons agreed with the shipyard and surveyor.
2. Components & Service Conditions
FUSHUN METAL forges the complete rudder assembly: rudder stocks, which carry rudder torque into the steering gear, and rudder pintles, the lower pivot pins supporting the rudder within the heel. These components operate in a wet, corrosive environment while transmitting full steering loads.
Because the rudder stock is a safety-critical rotating member, classification societies require a forged product rather than a casting or welding, so the grain flow follows the torque path and internal defects are closed out. The martensitic stainless 1.4006 is specified where seawater corrosion is critical, and the low-alloy 42CrMo4 and AISI 5140 where strength and machinability are the priority.
3. Grade Equivalents – 42CrMo4 / AISI 5140 / 1.4006
| Designation | Standard | Notes |
|---|---|---|
| 42CrMo4 / 1.7225 | EN 10250-3 | Standard rudder stock steel |
| AISI 5140 | SAE J404 | US chromium steel |
| 1.4006 / X12Cr13 / 410 | EN 10088-3 | Martensitic stainless option |
| SCM440 | JIS G4105 | Japanese equivalent |
| 40Cr / 1Cr13 | GB/T 3077 / GB/T 1220 | Reference only, not used in certification |
| Grade | C | Si | Mn | Cr | Mo |
|---|---|---|---|---|---|
| 42CrMo4 (1.7225) | 0.38-0.45 | 0.40 max | 0.60-0.90 | 0.90-1.20 | 0.15-0.30 |
| AISI 5140 | 0.38-0.43 | 0.15-0.35 | 0.70-0.90 | 0.70-0.90 | – |
| 1.4006 / 410 | 0.08-0.15 | 1.00 max | 1.50 max | 11.5-13.5 | – |
The 11.5-13.5% chromium content of 1.4006 provides seawater corrosion resistance for rudder stocks operating in a permanently wet environment.
4. Manufacturing Process
Forging. FUSHUN METAL forges rudder stocks with a minimum 4:1 reduction ratio on a 20/80 MN fast forging press, orienting grain flow along the torque path.
Heat treatment & machining. The stock is quenched and tempered, then machined to full geometry including keyways, tapers and coupling flanges.
Testing. Full-section UT and MT, with class surveyor witness at the required stages and optional protective surface treatments agreed to the vessel specification.
5. Standards & Certification
Rudder forgings are supplied to classification society rules with class certificates and witness points at the required stages. FUSHUN METAL holds factory approval from CCS, BV, DNV, GL, LR, KR and ABS, plus ISO 9001 and AS9120B quality system certification.
Related forging: marine shafting.
6. Typical Applications
Rudder stocks
Vertical shafts carrying rudder torque into the steering gear.
Rudder pintles
Lower pivot pins supporting the rudder within the heel.
Steering gear shafts
Torsion shafts and tiller connections for steering systems.
Corrosion-resistant stocks
1.4006 stainless where seawater corrosion is critical.
7. Inquiry Essentials
To quote your rudder forging, please provide the rudder stock drawing, the classification society, the required grade, and any surface treatment or witness requirements.
