Products FAQ

The rate at which the oxidation layer forms depends on climatic conditions. In outdoor environments with significant fluctuations between dry and wet conditions, it typically takes between six months and two years for a stable, dark brown protective layer to form. During the initial stage, rust streaks may form, so care should be taken to protect the surrounding building surfaces.

The choice depends primarily on strength requirements:

DH32: Yield strength 315 MPa. Suitable for most standard hull structures and offers good value for money.

DH36: Yield strength 355 MPa. Although the impact temperature is also -20°C, DH36 offers higher strength.

Recommendation: If the design allows for weight reduction, or for critical areas subject to high stress (such as hatch coamings and deckhead plates), the design may specify DH36; for standard hull plating, DH32 is usually sufficient and more economical.

ABS Grade DH32 is essentially a carbon-manganese steel and does not form a protective oxide layer like stainless steel. In marine environments, it must be used in conjunction with marine paint (anti-corrosion coating) and sacrificial anodes (cathodic protection). Typically, prior to processing, the steel plates undergo shot blasting or sandblasting and are coated with a primer.

The mechanical properties of ABS Grade DH32 shipbuilding steel plates are typically achieved through controlled rolling and heat treatment. The most common delivery conditions include:

TMCP: This is an advanced controlled rolling process that yields good low-temperature toughness and weldability.

Normalizing: For thicker gauges, normalising is usually employed to refine the grain structure.

Controlled rolling: Improving production efficiency.

Buyers should confirm three key documents and inspections:

1. Original classification society mill certificate.

2. Complete MTC mill test report with chemical and mechanical properties.

3. UT ultrasonic inspection and surface quality check to ensure no internal lamination or surface defects.

Yes, ABS DH32 has excellent weldability with low carbon equivalent. It is compatible with SAW, GMAW and SMAW welding processes.

Yes, DH32 is suitable for structural components on offshore platforms subject to high loads and operating at ambient temperatures of no less than -20°C. Where structures are exposed to extremely low temperatures or involve critical connection joints (such as TKY joints), it is usually required to use higher-grade EH32 steel or steel plates with Z-direction properties (Z25/Z35) to ensure resistance to laminar tearing.

Both have the same yield strength; the main difference lies in the impact test temperature. AH32 is tested at 0°C, whilst DH32 is tested at -20°C, making DH32 more suitable for colder or harsher sea conditions.

ABS Grade AH36, DH36, EH36 and FH36 shipbuilding steel plates have the same strength; the key difference lies in the test temperature for low-temperature impact toughness.

Yes, it has excellent weldability and is suitable for manual arc welding, gas shielded arc welding and submerged arc welding.