P355QH Vessel Plate for Boiler Drums, Exchangers & Tanks

What is P355QH Plate?

P355QH is a fine-grained, weldable, quenched and tempered (Q&T) pressure vessel steel plate conforming to European standard EN 10028-6:2017, designated under Steel Number 1.8866. It is primarily specified for pressure equipment such as boiler steam drums, heat exchangers, and storage tanks.

P355QH Pressure Vessels Plate Chemical Composition

Ladle analysis, maximum %, per EN 10028-6:2017:

P355QH PVQ Steel Plate Mechanical Properties

P355QH Vessel Plate Application Scenarios

1. Boiler drums and steam collectors. The classic use. Wall thickness is calculated from the hot proof strength, so the guaranteed Rp0.2 values translate directly into material saving, and the QT fine-grain structure handles the thermal gradient between the water side and the steam side.
2. Shell-and-tube heat exchangers. Shells and tube sheets see alternating hot and cold shocks as the unit cycles, and the tube-to-tubesheet joint needs a plate that welds cleanly and holds dimensional stability through PWHT. The low carbon equivalent is the reason QH grades are specified here over higher-carbon alternatives.
3. Spherical and process storage tanks. Spheres above roughly 50 m³, single-course welded vessels, and multi-layer shrink-fit or wrapped vessels in the second and third pressure-vessel classes are built from this grade in refineries and chemical plants, as are LPG and oil/gas storage where the operating temperature stays in the hot-to-ambient band.
4. Reactors and process columns. Ammonia synthesis towers, polymerisation reactors, hydrogenation and rectification columns. Here the selection driver is usually the combination of pressure, temperature and a mildly aggressive medium; note that the medium itself is a corrosion question, answered by cladding or corrosion allowance rather than by the base grade.
5. Hydropower and heavy penstock sections. High-head penstocks and spiral cases use QT plate for the strength-to-thickness ratio, with the −20 °C impact margin covering alpine and northern sites.

P355QH Vessel Plate for Boiler Drums, Exchangers & Tanks Specifications

Design Temperature: P355Q vs P355QH vs P355QL1 vs P355QL2

Why Choose GNEE for P355QH Plate Orders

1. Cut-to-drawing supply: plates delivered as finished parts to your cutting list, so drum courses and shell cans go straight to fit-up.
2. Inspection arranged to your specification: UT, Z-direction and Charpy testing booked with production rather than added afterwards; SGS, TÜV or BV witness available for 3.2 certification.
3. Multiple logistics options are available: full container sea freight, less than container load (LCL), and cross-border land transport to optimize logistics costs; the boards are coated with film and packaged with rust-proof materials to prevent rust and scratches during sea transport.

FAQ

Can you supply P355QH cut and bevelled to our cutting list?
Yes. Most orders ship as cut, bevelled and blasted parts rather than full plates. Send the cutting list with the enquiry and we quote the finished parts.

What supplementary testing is usual for spherical tank plate?
UT to EN 10160 or ASTM A578 is standard for critical courses, and Z-direction testing to EN 10164 (Z25 or Z35) is added where through-thickness restraint at nozzles and joints is a concern. Both are line items on the quotation.

What are typical lead times and minimum quantities?
Stock thicknesses in the 10–50 mm range ship quickly and in small quantities. Thicknesses outside stock are booked as mill orders with mill minimums and production lead time. Give us size, quantity and port for a firm answer.

Do you provide UT and impact test reports?
Yes, UT reports to the specified standard and Charpy results to the agreed temperature are supplied with the EN 10204 certificate.