P265GH
1.0425
Non-alloy quality steel for pressure equipment with specified elevated-temperature properties · EN 10028-2:2017 — grade-specific requirements for flat products with elevated-temperature properties · EN 10028-1:2017 — general requirements for flat products for pressure purposes
P265GH is a weldable carbon-manganese pressure-vessel steel supplied principally in the normalized condition. It combines moderate room-temperature strength, specified transverse Charpy toughness down to −20 °C and thickness-dependent 0.2% proof strength values through 400 °C. Its identification is incomplete without the product standard, product form, thickness and delivery condition; P265GH pipe, forging and plate products are governed by different specifications and must not be substituted solely by matching the grade name or material number.
- Non-alloy quality steel for pressure purposesClassification · EN 10028-2 classifies P235GH, P265GH, P295GH and P355GH as non-alloy quality steels.
- +NUsual delivery condition · Normalizing rolling may replace a separate normalizing treatment at the manufacturer's discretion.
- 265 MPa minimum at t ≤ 16 mmRoom-temperature yield · The minimum decreases with thickness, reaching 185 MPa for 150 < t ≤ 250 mm.
- 410–530 MPa and A ≥ 22% through 100 mmTensile properties · Transverse test direction; the tensile range decreases for thicknesses above 100 mm.
- 27 J at −20 °C; 34 J at 0 °C; 40 J at +20 °CCharpy toughness · Minimum transverse KV2 values. Test-piece feasibility and reduced-section provisions depend on product thickness and EN 10028-1.
- Rp0.2 specified from 50 °C to 400 °CElevated-temperature strength · At t ≤ 16 mm, the minimum is 205 MPa at 200 °C and 150 MPa at 400 °C.
Overview
- Designation system
- EN 10027 steel name and steel number systems
- Product forms
- Hot-rolled plate, Sheet, Wide flat and strip covered by the EN 10028 series
- Condition
- +N normalized, Normalizing rolled in place of normalizing, as permitted by EN 10028-2, Untreated delivery only by agreement, with testing requirements governed by the standard
- Density
- 7.85 g/cm³ (Representative density for carbon steel; not a grade acceptance requirement in EN 10028-2.)
What the designation defines
The designation follows EN 10027-1. “P” identifies steel for pressure purposes, “265” is the specified minimum room-temperature yield strength in MPa for the smallest thickness range, “G” introduces another characteristic, and “H” denotes high-temperature properties. The associated European steel number is 1.0425.
EN 10028-2 covers flat products for pressure equipment. It supplies the grade-specific chemistry, delivery condition and mechanical requirements, while EN 10028-1 controls general matters such as ordering information, inspection, sampling, dimensions, tolerances, surface condition, internal soundness and marking. Compliance should therefore be stated as P265GH to EN 10028-2, not simply as “P265GH steel.”
P265GH is also used as a steel name in standards for tubes and other pressure products. Those specifications have their own chemistry, property, dimensional and testing provisions. A tube certified to EN 10216-2 or EN 10217-2 is not automatically acceptable where EN 10028-2 plate is required.
Chemical composition and metallurgical character
| Element | Requirement, mass % | Technical significance or qualification |
|---|---|---|
| C | ≤ 0.20 | Controls strength, hardenability and weldability. |
| Si | ≤ 0.40 | Deoxidizing and solid-solution element. |
| Mn | 0.80–1.40 | Minimum may be 0.20 percentage point lower when nominal thickness is below 6 mm. |
| P | ≤ 0.025 | Residual impurity restricted for toughness and weldability. |
| S | ≤ 0.010 | Low limit supports toughness and inclusion control. |
| Al total | ≥ 0.020 | Al content is determined and reported in the inspection document. |
| N | ≤ 0.012 | Al/N ratio must be at least 2. |
| Cr | ≤ 0.30 | Residual-alloy limit. |
| Cu | ≤ 0.30 | A lower Cu limit or Cu/Sn restriction may be agreed where hot formability is important. |
| Mo | ≤ 0.08 | Residual-alloy limit; P265GH is not a molybdenum creep-resistant grade. |
| Nb | ≤ 0.030 | Restricted microalloy content. |
| Ni | ≤ 0.30 | Residual-alloy limit. |
| Ti | ≤ 0.03 | Maximum. |
| V | ≤ 0.02 | Maximum. |
| Cr + Cu + Mo + Ni | ≤ 0.70 | Combined residual-alloy limit. |
These are cast-analysis limits. Product analysis is assessed using the separate permissible deviations in EN 10028-2; it should not be compared directly with the cast limits without applying those rules.
P265GH is essentially an aluminium-killed carbon-manganese steel with restricted phosphorus, sulphur and residual alloying elements. In the normalized condition it normally develops a ferrite-pearlite microstructure. It has no intentional chromium-molybdenum alloy system that would make it oxidation resistant, corrosion resistant or equivalent to a dedicated creep-resistant steel.
Elements not listed by the standard are not to be intentionally added without purchaser agreement, except as necessary for finishing the cast. This matters when reviewing certificates containing boron or other residual elements that may influence hardenability and welding behavior.
Delivery condition and heat treatment
The usual delivery condition is +N. The manufacturer may replace separate normalizing with normalizing rolling for P265GH. If verification after a conventional normalizing cycle is important—for example because the fabricator will normalize after hot forming—tests in a simulated normalized condition and their frequency should be agreed at enquiry and order.
| Condition or operation | Status | Practical consequence |
|---|---|---|
| +N | Usual delivery condition | Mechanical-property requirements apply to normalized material; normalizing rolling is permitted as a replacement. |
| Untreated delivery | By agreement only | The product may be shipped untreated, but the specified properties are established on test pieces in the usual delivery condition prescribed by the standard. |
| Normalizing | 890–950 °C guideline | Informative EN 10028-2 heat-treatment range. Actual procedure must account for section size, furnace practice and the fabrication specification. |
| PWHT or stress relief | Fabrication-code dependent | Excessive time-temperature exposure can reduce strength. Simulated heat-treated testing should be considered when severe or repeated PWHT cycles are expected. |
The standard's normalizing range is guidance, not a complete heat-treatment procedure. Heating rate, equalization, cooling, component geometry and prior forming history remain the responsibility of the fabricator and governing construction code.
Room-temperature mechanical requirements
| Nominal thickness t, mm | Minimum ReH, MPa | Rm, MPa | Minimum elongation A, % |
|---|---|---|---|
| t ≤ 16 | 265 | 410–530 | 22 |
| 16 < t ≤ 40 | 255 | 410–530 | 22 |
| 40 < t ≤ 60 | 245 | 410–530 | 22 |
| 60 < t ≤ 100 | 215 | 410–530 | 22 |
| 100 < t ≤ 150 | 200 | 400–530 | 22 |
| 150 < t ≤ 250 | 185 | 390–530 | 22 |
Values apply to the transverse direction. The “265” in the grade name is therefore not a universal minimum for every thickness.
| Test temperature | Minimum KV2 |
|---|---|
| −20 °C | 27 J |
| 0 °C | 34 J |
| +20 °C | 40 J |
These values do not establish an unrestricted minimum design-metal temperature. Component thickness, stress state, welds, heat-affected zones, test-piece size and the applicable pressure-equipment code must also be considered.
Strength at elevated temperature
The defining advantage over a general structural carbon steel is the specification of minimum 0.2% proof strength at elevated temperature. The values are thickness dependent and end at 400 °C for P265GH. They are material-property requirements, not allowable design stresses.
| Nominal thickness t, mm | 50 °C | 100 °C | 150 °C | 200 °C | 250 °C | 300 °C | 350 °C | 400 °C |
|---|---|---|---|---|---|---|---|---|
| t ≤ 16 | 256 | 241 | 223 | 205 | 188 | 173 | 160 | 150 |
| 16 < t ≤ 40 | 247 | 232 | 215 | 197 | 181 | 166 | 154 | 145 |
| 40 < t ≤ 60 | 237 | 223 | 206 | 190 | 174 | 160 | 148 | 139 |
| 60 < t ≤ 100 | 208 | 196 | 181 | 167 | 153 | 140 | 130 | 122 |
| 100 < t ≤ 150 | 193 | 182 | 169 | 155 | 142 | 130 | 121 | 114 |
| 150 < t ≤ 250 | 179 | 168 | 156 | 143 | 131 | 121 | 112 | 105 |
EN 10028-2 does not give P265GH proof-strength requirements at 450 °C or 500 °C.
EN 10028-2 includes informative mean creep-strain and creep-rupture reference data for P235GH and P265GH. Those data are not guaranteed minimum grade properties and expressly do not mean that continuous operation is acceptable up to every listed temperature. Long-duration design must use the governing construction code, design life, stress, oxidation allowance and applicable material assessment.
Welding and fabrication implications
P265GH is intended to be weldable using established procedures for carbon-manganese pressure steels. Weldability does not eliminate the need for a qualified WPS. Preheat, heat input, consumable classification, interpass temperature, hydrogen control and PWHT depend on thickness, restraint, joint design, actual heat analysis, service requirements and the governing fabrication code. EN 1011-1 and EN 1011-2 provide relevant welding guidance.
Hot forming, heavy cold forming and subsequent heat treatment can alter the normalized microstructure and the certified properties. The fabrication specification should define whether renormalizing is required and whether tests representing the final thermal cycle are needed. For components receiving prolonged or repeated PWHT, the steelmaker should be informed at the ordering stage so that simulated heat-treated tests can be agreed.
Service limitations and optional testing
| Characteristic | Included in the basic grade? | What to specify when needed |
|---|---|---|
| Strength through 400 °C | Yes | Use the thickness-dependent EN 10028-2 values and the allowable stress from the construction code. |
| Corrosion resistance | No | Define corrosion allowance, coating, lining or an alternative alloy from the process environment. |
| Sour-service HIC resistance | No | Specify HIC testing and an acceptance class under EN 10028-2/EN 10229 or the project standard. |
| Through-thickness properties | No | Specify an appropriate Z-quality requirement where lamellar tearing risk exists. |
| Enhanced ultrasonic quality | Not inherent in the grade name | State the required UT standard, class, scanning extent and acceptance criteria. |
| Maximum CEV | Optional by agreement | State the required maximum and confirm reporting on the inspection certificate. |
| 40 J option | Available by agreement | Define the applicable temperature, orientation and test requirements. |
| Simulated fabrication heat treatment | Optional by agreement | Provide the complete thermal cycle and required testing frequency. |
Carbon and low-alloy steels can suffer hydrogen-induced cracking in wet H₂S environments. Ordering ordinary P265GH without an agreed HIC test does not demonstrate sour-service resistance.
Ordering and certificate review
| Item | What should be stated or checked |
|---|---|
| Specification | EN 10028-2 edition, together with the applicable EN 10028-1 edition. |
| Grade | P265GH or 1.0425; avoid relying on an informal commercial description such as boiler plate. |
| Product and dimensions | Plate, sheet or strip dimensions, tolerances and mass basis. |
| Delivery condition | +N unless another permitted condition is explicitly agreed. |
| Inspection document | Required EN 10204 document type, commonly 3.1 or project-required 3.2; do not assume 3.2 is automatic. |
| Mechanical tests | Confirm thickness range, transverse orientation, test temperatures and whether reduced impact specimens apply. |
| Chemistry | Review cast analysis, product analysis when ordered, Al/N requirement and actual CEV for welding. |
| Fabrication cycle | State hot forming, normalizing and PWHT cycles that the material must withstand. |
| Additional examinations | HIC, UT, through-thickness properties, surface quality or other project-specific acceptance criteria. |
| Traceability | Heat number, plate identification, marking transfer and segregation during cutting and fabrication. |
When reviewing a certificate, compare the results with the correct thickness row and delivery condition. A reported yield strength above 265 MPa does not by itself demonstrate compliance: chemistry, tensile range, elongation, impact results, heat treatment, test orientation, dimensions, traceability and all ordered options must also conform.
Substitution and related grades
Substitution should be assessed against the complete material specification and construction code. Similar room-temperature tensile strength is insufficient where elevated-temperature proof strength, Charpy temperature, heat treatment, product form, certification or design-code approval differs. This is particularly important when comparing P265GH with ASTM/ASME pressure-vessel grades, which use different property systems and code allowables.
Sources
- BS EN 10028-2:2017 — Flat products made of steels for pressure purposes, Part 2British Standards Institution
- EN 10028-2:2017 — Standard text reproductionCEN text reproduced by StudyLib
- SIST EN 10028-2:2017 previewSlovenian Institute for Standardization / iTeh
- EN 10027-1:2016 — Designation systems for steels, steel namesCEN / iTeh
- ISO 9328-2:2018 — Steel flat products for pressure purposes, Part 2International Organization for Standardization
- Heat-resistant pressure-vessel steelsSalzgitter Flachstahl GmbH
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