Q390D Steel Plate Applications & Ordering Guide
GB/T 1591 Q390D high-strength low-alloy structural steel is specified for industrial fabrications where the drawing or material list names this grade. This applications page explains where the grade is used, what service conditions drive selection, and which certificate details belong on the purchase order. Gangsteel supplies GB/T 1591 Q390D high-strength low-alloy structural steel with EN 10204 mill test certificates.
Typical Applications and Service Conditions
GB/T 1591 Q390D high-strength low-alloy structural steel plate is ordered for pressure equipment, process vessels, heat-exchanger related fabrications, structural members under the governing code, and project packages that call the grade by name. Match the mill test certificate grade mark to the calculation sheet; do not treat near-equivalents as automatic substitutes.
Service drivers include the design temperature and pressure of the governing code (ASME, EN/PED, class society, or project specification), weld procedure qualification needs, toughness or creep allowables where applicable, and inspection scope. Delivery condition As-rolled / normalized / TMCP per thickness and quality; D quality impact -20 deg C should be stated explicitly on the purchase order.
Industry Use Cases
Pressure equipment and process: shells, heads, and related platework when drawings name GB/T 1591 Q390D high-strength low-alloy structural steel. Power and energy: boiler and heat-recovery fabrications under the ordered edition. Marine / offshore (when classed): only when the society material list names this exact grade stamp. Always keep heat-number traceability on cut pieces.
Chemical Composition - Supporting Data (GB/T 1591 Q390D high-strength low-alloy structural steel)
Ladle analysis per GB/T 1591 for Q390. Thickness-dependent yield. D = -20 deg C impact.
| Element / rule | Requirement |
|---|
| C, max | 0.20 |
| Si, max | 0.55 |
| Mn, max | 1.70 |
| P, max | 0.030 |
| S, max | 0.030 |
| Nb / V / Ti / Al | microalloy / fine-grain per standard options |
Mechanical Properties - Supporting Data (GB/T 1591 Q390D high-strength low-alloy structural steel)
Confirm thickness, specimen orientation, and any supplementary impact, UT, or hardness requirements on the PO.
| Property | Requirement |
|---|
| Yield ReL, min (t<=16 mm) | 390 MPa |
| Yield ReL, min (thicker bands) | 380 / 360 / 340 / 320 MPa by thickness |
| Tensile Rm | 490-650 MPa (thin); 470-620 MPa thicker bands |
| Elongation A, min | 20% (19% some thicker) |
| Impact KV2 at -20 C, min | 34 J |
Related / Near-Equivalent Grades
Near-equivalents are for cross-reference only. They are not automatic code substitutes. Substitution requires engineer approval and matching certificate scope.
| System | Grade | Note |
|---|
| EN 10025-3 | S355NL / S420N family (approx.) | Not automatic substitute |
| GB/T 1591 | Q390B/C/E | Same strength, different impact quality |
Frequently Asked Questions
Where is GB/T 1591 Q390D high-strength low-alloy structural steel typically applied?
GB/T 1591 Q390D high-strength low-alloy structural steel is applied where design documents, class material lists, or purchaser specs name this grade for pressure, process, structural, or marine fabrications as applicable. Match the MTC marking to the drawing.
What service conditions drive selection of GB/T 1591 Q390D high-strength low-alloy structural steel?
Design temperature and pressure, toughness or creep allowables, weldability, corrosion or process media, and the governing code edition drive selection. Delivery condition As-rolled / normalized / TMCP per thickness and quality; D quality impact -20 deg C must align with the ordered specification.
Can a near-equivalent replace GB/T 1591 Q390D high-strength low-alloy structural steel on an applications drawing?
Not without redesign and written approval. Near-equivalents differ in chemistry, heat treatment, impact temperature, or product form. Commercial swaps create non-conformance when the dossier names GB/T 1591 Q390D high-strength low-alloy structural steel.
What fabrication notes matter for GB/T 1591 Q390D high-strength low-alloy structural steel?
Use approved WPS/PQR packages for the thickness and filler, control heat input, and preserve heat-number traceability on cut pieces. State any supplementary UT, PMI, or impact tests on the purchase order.
What certificate and marking should an applications PO demand?
EN 10204 3.1 is standard; 3.2 when a purchaser-appointed inspector witnesses tests. The MTC should show heat analysis, tensile results, delivery condition, and heat number aligned with GB/T 1591 Q390D high-strength low-alloy structural steel.
How should I RFQ GB/T 1591 Q390D high-strength low-alloy structural steel plate from Gangsteel for a project?
Send GB/T 1591 Q390D high-strength low-alloy structural steel, thickness x width x length (or nesting list), quantity, delivery condition, optional NDT/PMI, certificate type, destination, and any dual-mark needs. Note the end use when special flatness or cut-to-size packaging is required.
Ordering and Mill Certificates
State grade GB/T 1591 Q390D high-strength low-alloy structural steel, dimensions, quantity, delivery condition, optional NDT/PMI, and certificate (EN 10204 3.1 standard; 3.2 when third-party inspection is ordered). Gangsteel supplies export plate and related products with mill test certificates. Contact Gangsteel for stock and mill production RFQs.
