How to Choose Stainless Steel Seamless Pipes for Ship Building

Selecting the right stainless steel seamless pipes is critical for ensuring the safety, longevity, and performance of marine vessels. XINHANG Special Material, as a manufacturer with 18+ years of expertise in industrial and marine-grade pipes, we outline key technical considerations below.

1. Material Grade & Corrosion Resistance

Marine environments demand grades that resist pitting, crevice corrosion, and stress corrosion cracking. Common choices include:
● 316L Austenitic Stainless Steel: Ideal for general ship piping systems due to its excellent resistance to saltwater corrosion and acidic chemicals. It’s widely used in chemical tankers and boiler tubes.

● Duplex/Super Duplex (e.g., UNS S32250, S32750): For harsh offshore applications (e.g., risers, heat exchangers). These offer 2x higher strength than 316L, superior stress corrosion cracking resistance, and weight savings of up to 20% compared to copper-nickel alloys.

Comparison of Stainless Steel Grades for Marine Use

2. Dimensional Precision & Mechanical Properties

Seamless pipes for ships must adhere to strict dimensional tolerances (e.g., outer diameter: ±0.3mm for cold-drawn pipes; wall thickness: ±10%). Key mechanical benchmarks include:
● Tensile Strength: 410–610 MPa (depending on grade, e.g., 490 for high-pressure systems).
● Low-Temperature Toughness: Essential for Arctic vessels (impact toughness ≥21% elongation).

3. Compliance with Marine Certifications

Pipes must meet international ship classification standards:
● Class Society Approvals: CCS, DNV, ABS, LR, NK, RINA, GL,KR or BV.
● Testing Protocols: Hydrostatic, HIC (Hydrogen-Induced Cracking), and SSC (Sulfide Stress Corrosion) tests for pipes in sour service.

4. Manufacturing Process & Traceability

Opt for pipes produced via:
● Mandrel Rolling or Cold Drawing: Ensures uniform wall thickness and surface integrity.
● Pickling & Passivation: Removes scale and enhances corrosion resistance (using HNO₃/HF mixtures).
● Full Traceability: Mill test certificates validating chemical composition and heat treatment (e.g., solution annealing for duplex grades).

5. Lifecycle Cost Considerations

While initial costs for duplex grades are higher, their 5x longer service life and minimal maintenance reduce total ownership costs. For example, super duplex spray systems save ~15% in weight and 38% in material usage versus copper-nickel alternatives.

Your Trusted Partner: XINHANG Special Material
With 18+ years of specialized manufacturing expertise, XINHANG Special Material guarantees seamless pipes that exceed all above requirements:, we provide CCS, DNV, ABS, LR, NK, RINA, GL,KR and BV-certified pipes with tailored solutions for offshore, cargo, and naval vessels