Key Differences Between BV AH36, DH36, and EH36 Shipbuilding Steel Plates

1. Differences in Low-Temperature Toughness

2. Differences in Chemical Composition

The minimum manganese content for BV AH36 is 0.7%, while for BV DH36 and EH36, it is 0.9%. The high manganese content refines the grain structure and improves low-temperature toughness.

BV EH36 has the strictest controls on harmful impurities (P/S) and gaseous nitrogen.

3. Differences in Production Processes

BV AH36: Conventional hot-rolling; the process has the lowest technical requirements.

BV DH36: Must use a controlled rolling and controlled cooling (TMCP) process to ensure toughness at –20°C.

BV EH36: Thick-gauge plates require normalizing or advanced TMCP to strictly control grain size and prevent low-temperature brittle fracture.

4. Differences in Welding Procedures

BV AH36: For thinner sections, welding preheating requirements are less stringent.

BV DH36/EH36: Preheating and interpass temperature control for thick plates are more stringent; EH36 has the highest threshold for welding procedure qualification.

5. Differences in Typical Applications

BV AH36: Bulk carriers and container ships operating in temperate and tropical waters; standard hulls, superstructures, non-pressure bulkheads, and inland waterway vessels.

BV DH36: Commercial vessels in cold waters; main hulls and side walls of oil tankers; bottom plates; offshore wind turbine foundations; and offshore platforms.

BV EH36: Polar vessels, icebreakers, LNG containment structures, and critical load-bearing components of cold-water offshore platforms.