Technical guide · 2026-08-03
Pressure Vessel Steel
Pressure-vessel steels are plate and related products ordered for boilers, vessels, tanks and pressure equipment under material specifications coordinated with a construction code. Strength alone is insufficient: thickness, design temperature, notch toughness, heat treatment, weld procedure and examination determine acceptance.
01
Definition and boundary
A structural plate of similar strength is not automatically a pressure-vessel plate because melting, testing, heat treatment, certification and code recognition can differ.
Reference information only: final acceptance is controlled by the ordered product specification, condition, dimensions and certified test results.
02
How the material system works
Controlled chemistry and processing support weldability and notch toughness.
Normalizing or other heat treatment may be required by grade/thickness/code.
PWHT changes the final material/weld condition and must be considered in qualification.
03
Representative grades and systems
| Grade or system | Selection focus | Qualification |
|---|---|---|
| Carbon-steel vessel plate grades with different strength levels. | Verify the ordered product specification, condition and dimensions before substitution. | |
| P265GH | EN pressure-purpose steel requiring EN product/code context. | Verify the ordered product specification, condition and dimensions before substitution. |
| Q345R | GB pressure-vessel plate grade governed by its own requirements. | Verify the ordered product specification, condition and dimensions before substitution. |
04
Properties and trade-offs
Strength and elongation requirements vary with grade and thickness.
Notch toughness is tied to test temperature, specimen and acceptance criteria.
Code allowable stress is not the same as a room-temperature tensile value.
05
Product forms and supply conditions
06
Applications and selection
Applications and selection
- Process and storage pressure vessels
- Boilers, drums and heat-exchanger shells
- LPG, energy and low-temperature equipment when qualified
Properties and trade-offs
- Use design code, pressure, temperature and fluid hazard to establish material requirements.
- Select grade/thickness with toughness and PWHT effects verified.
- Do not substitute cross-standard plates without engineering and code approval.
07
Fabrication, durability and inspection
Use qualified welding procedures based on carbon equivalent, thickness, restraint and hydrogen control.
Account for rolling direction, residual stress, heat-affected-zone properties and distortion.
Apply coating, drainage, corrosion allowance or another material strategy for the actual exposure.
08
Procurement checklist
- State the governing product specification, grade, dimensions, tolerances and delivery condition.
- Define impact testing, NDE, through-thickness, heat treatment, weldability and traceability when applicable.
- Request an MTC tied to heat/lot identity and list all supplementary requirements in the purchase order.
09
Standards, sources and review
Standards and designation context
- ASTM A516/A516M and ASTM A20/A20M general requirements
- ASME BPVC material and construction-code requirements where applicable
- EN 10028 or GB/T vessel-plate specifications for their respective systems