Mirror Polished
Stainless Steel Marine Castings
ISO 9001 certified investment casting foundry in China. SS316 / 316L marine castings with #8 mirror polish (Ra ≤ 0.4 μm), passivation per ASTM A967, and 500h salt spray certification. Factory direct — 24h quote response.
Polish Grades Available
From Satin to Full Mirror — All Grades In-House
#4 Brushed
Ra 0.8–1.6 μm
Directional satin finish. Standard for marine deck hardware and structural fittings.
Typical use: Deck cleats, stanchion bases, fairleads
#6 Bright
Ra 0.4–0.8 μm
Semi-mirror finish with visible grain. Corrosion-resistant and aesthetically premium.
Typical use: Handrail fittings, helm components, portlight frames
#8 Mirror
Ra ≤ 0.4 μm
Full mirror finish. Zero grain lines. Maximum corrosion resistance in saltwater.
Typical use: Luxury yacht hardware, decorative cleats, custom OEM marine parts
Typical Parts
Marine Castings We Produce
Don't see your part? We cast and polish custom OEM marine components from your drawings. Send us your drawing →
6-Step Process
From Casting to Mirror Finish — Full In-House Control
Silica Sol Investment Casting
Near-net-shape casting with Ra 3.2–6.3 μm as-cast surface. Minimal material removal required for polishing.
Normalising & Heat Treatment
Full stress relief to prevent distortion during polishing. Hardness verified by Brinell testing.
CNC Machining (if required)
Critical dimensions machined to ±0.05 mm before polishing to preserve tolerances.
Progressive Grinding
120 → 240 → 400 grit sequence removes casting skin and machining marks systematically.
Buffing & Mirror Polishing
Sisal → cotton buff sequence with polishing compounds achieves Ra ≤ 0.4 μm mirror finish.
Passivation (ASTM A967)
Citric acid passivation restores chromium oxide layer after polishing. Salt spray tested per ASTM B117.
Quality Documentation
Full Traceability. Every Batch.
Why Huayun
Casting + Polishing Under One Roof
20+ years specialising in mirror polished stainless steel castings for marine OEM customers
ISO 9001:2015 certified. Full material traceability from melt to finished part
In-house spectrometer, CMM, surface roughness tester, and salt spray chamber
Silica Sol investment casting — superior as-cast surface vs. water glass process
SS316L standard. Duplex 2205 and Super Duplex 2507 available for extreme environments
NDA signed before drawing review. IP protection guaranteed
Have a complex mirror polish requirement? Our engineers have handled Ra ≤ 0.2 μm super-mirror finishes for luxury yacht hardware. Send us your drawing and we'll give you a frank assessment.
FAQ
Common Questions
Request a Quote
Get a 24-Hour Quote on Mirror Polished Marine Castings
Send us your drawing (DWG, STEP, PDF) or describe your part. We'll respond with a tooling cost estimate and unit price within 24 hours.