Process & product
Low-residual-stress ship plate
Thin hot-rolled ship plate (up to 10 mm) traditionally carries enough residual stress to warp after cutting and welding — a recurring problem in car-ferry and tanker superstructure work. WISCO's low-residual-stress plate, developed and validated with CSSC Guangzhou Shipyard International over three years, addresses this before the plate leaves the mill.
Where the problem starts
Ro-ro and car-ferry vessels need large volumes of thin plate. Heavy-plate mills can produce it, but with longer lead times and higher cost. Hot-strip mills are faster and more precise, but conventional hot-rolled plate carries higher residual stress — it shows up as warping after cutting and welding, and normally needs extra flame-straightening to meet hull flatness tolerances.
WISCO's development
WISCO and CSSC Guangzhou Shipyard International have jointly developed low-residual-stress hot-rolled ship plate since June 2022, working through flatness control and flame-forming validation across successive trials. It went into a research-vessel section in 2023, a car-ferry hull section in 2024, and an ocean-going tanker section in 2025 — now in stable batch use, with over 210,000 tonnes of low-stress AH36 already applied on inland vessels alone.
Measured results
- Residual stress
- Lower than single-pass rolled plate, markedly lower than standard hot-rolled ship plate
- Flatness after cutting & welding
- 46% to 76% better than standard hot-rolled ship plate
- Flame-forming labour
- Reduced by about 50%
Figures from WISCO / CSSC Guangzhou Shipyard International joint trial data, comparing low-residual-stress plate against standard hot-rolled ship plate of the same thickness.
Development and validation
- 1
June 2022 — first trial
- 2
August 2022 — second trial, flatness control resolved
- 3
October 2022 — third trial, flame-cutting and forming confirmed good
- 4
September 2023 — applied to a research vessel
- 5
January 2024 — applied to a car-ferry hull section
- 6
February 2025 — applied to an ocean-going tanker section
Vessel types in service
Validated and in use across the following vessel types, built by CSSC Guangzhou Shipyard International and other yards. This is WISCO and its shipyard partners' own development record, not a list of ZCMetals deliveries.
Car ferries and ro-pax vessels, ocean-going tankers, special-purpose vessels, ocean-going fishing vessels, inland ro-ro vessels, research vessels
How to order
Low-residual-stress plate is available through our WISCO first-tier distributor channel, in AH36 and other common hull structural grades. State the application — a car ferry or ro-ro thin-plate project, for example — in your enquiry, and we will confirm thickness, specification and lead time.
Ask about low-residual-stress plate
Tell us the grade, thickness and application. We will confirm whether low-residual-stress plate fits your project.