P265GH (1.0425) open-die forgings

Parts are produced from ingot or continuous-cast bloom by open-die forging or ring rolling, then normalised and tested as one traceable heat. Rough and finish machining are done in-house.

• Seamless rolled rings and forged rings. Shell courses, tyre rings, retaining rings, bearing races and reinforcing rings.
• Discs, tubesheets and tube plates. Heat-exchanger tubesheets, channel covers, blind covers and closure plates, drilled and grooved to drawing.
• Sleeves, bushes, hollow bars, cylinders and barrels. Trepanned or expanded hollows for pressure housings and casings.
• Shafts, round bars, stepped shafts and hubs. Upset and drawn on the press, with UT after normalising.
• Valve bodies, bonnets, stems, closures and seat rings. Near-net blocks and shaped forgings for gate, globe, ball and check valves.
• Girth flanges, cover flanges, long weld-neck flanges and nozzle necks. Self-reinforced FVC-type nozzles included.
• Shell-and-tube heat exchanger components. Channel barrels, girth flanges, floating-head covers and spacer rings.

Parts can be supplied as-forged with machining allowance, rough machined to drawing, or finish machined. State which on the enquiry so that forging allowance and test-prolongation positions can be planned correctly.

P265GH is a carbon–manganese steel with no deliberate alloying. The low carbon ceiling and the tight limits on residual elements are the reason it welds well. The combined limit on Cr + Cu + Mo + Ni also keeps hardenability predictable in heavy forged sections.

Combined residual limit: Cr + Cu + Mo + Ni ≤ 0.70 %. Total aluminium is specified as a minimum for fine-grain treatment. Product analysis tolerances apply per EN 10028-1. Forgings ordered to EN 10222-2 carry that standard’s own composition limits, which are close to the flat-product limits above without being identical. Order against the edition named in your specification.

Yield strength drops as section thickness increases. A heavier section cools more slowly through the normalising transformation and forms a coarser ferrite–pearlite structure. This matters more for forgings than for plate. A 300 mm thick forged tubesheet is governed by the values at the bottom of the table, not by the headline 265 MPa figure.

Longitudinal test pieces give higher values than the transverse minima shown. Impact testing below −20 °C is not covered by the grade. For genuinely low-temperature duty, specify a nickel steel to EN 10222-3.

Elevated-temperature behaviour

The GH suffix means minimum 0.2 % proof strength values are specified at elevated temperature. EN 10028-2 tabulates these up to roughly 400 °C for P265GH. Above that range the grade is no longer creep-competitive, and a molybdenum-bearing steel such as 16Mo3 (1.5415) or a Cr–Mo steel such as 13CrMo4-5 (1.7335) is normally specified. Ask for the proof-strength table from the edition your design code references, since values have been revised between editions.

Forging and normalising

P265GH is forged from a starting temperature of roughly 1150 to 1250 °C and finished above the transformation range so that the structure recrystallises fully. Every forging is then normalised at 890 to 950 °C and cooled in still air. Normalising refines the grain coarsened by the forging heat and restores uniform properties through the section. Where the customer’s fabrication route includes post-weld heat treatment, a simulated PWHT cycle can be applied to the test prolongation so that certified properties reflect the as-installed condition.

Welding

Weldability is the practical reason P265GH gets chosen over stronger grades. Carbon is capped at 0.20 % and there is no deliberate alloying, so the grade welds with SMAW, GTAW, GMAW and SAW using standard carbon-steel consumables. Preheat is driven by section thickness, joint restraint and hydrogen control rather than by the steel’s hardenability. Post-weld heat treatment, when the governing pressure-equipment code calls for it, is normally carried out in the 550 to 620 °C band. Confirm the exact soak against EN 13445, ASME VIII or whichever code applies to the vessel.

Machining

In the normalised condition P265GH machines easily but is on the gummy side, as low-carbon steels tend to be. Sharp tooling, positive rake and generous feed give better surface finish than reduced feed. Hardness after normalising usually sits in the 120 to 160 HB range.

No grade in another standard is an exact one-to-one replacement for P265GH, because chemistry tolerances, test directions and impact requirements differ between standards systems. The table lists the counterparts most often accepted in cross-standard supply. It is a starting point for a technical deviation request. It is not authority to substitute.

If your specification names an ASTM grade and you are buying a forging from Europe or China, say so at enquiry stage. Dual certification to EN 10222-2 and ASTM A105 or A266 is possible on many parts, but it constrains the chemistry aim and has to be agreed before the heat is melted.

The three grades share a family, a normalised delivery condition and similar fabrication behaviour. They differ in strength, and therefore in wall thickness and weight.

If the calculated wall in P265GH is buildable and weldable, stay on P265GH. It costs less, is easier to source and welds more easily. Move up to P355GH when wall thickness in P265GH starts to drive PWHT, crane capacity or lead time. Move to 16Mo3 when temperature rather than pressure is the governing constraint.

Parts outside this envelope are reviewed case by case. Send the drawing and we will confirm whether it falls inside our press capacity.

Each P265GH order ships with a document package tied to one heat number, hard-stamped on the part.

• Chemical analysis. Ladle analysis by spectrometer, product analysis on request, PMI verification where specified.
• Tensile testing. To EN ISO 6892-1, on test prolongations taken at the position the standard or customer requires.
• Charpy V-notch impact testing. To EN ISO 148-1, three specimens per set, at −20 °C or the specified temperature.
• Hardness survey. Brinell, with mapping across large tubesheets and covers when asked.
• Ultrasonic testing. To EN 10228-3 or ASTM A388, after normalising, with acceptance class stated on the order.
• Magnetic particle testing. To EN 10228-1 on machined surfaces where required.
• Dimensional report. Against the customer drawing, with a marked-up copy in the pack.
• Certification. EN 10204 3.1 as standard; 3.2 countersigned by TÜV, SGS, BV, DNV or Lloyd’s Register on request. PED 2014/68/EU material appraisal and AD 2000-Merkblatt W0 conformity can be arranged.

An incomplete enquiry is the usual cause of delay at quotation stage. Send the following and we normally reply within one working day.

1. Send the drawing or the rough dimensions. A PDF or STEP file is ideal; for a ring, outside diameter, inside diameter and height are enough to start.
2. Name the standard and edition. For example EN 10222-2:2017 P265GH, or the customer specification that governs the order.
3. State quantity and delivery condition. Prototype quantities and series orders are priced differently. Say whether you want as-forged, rough machined or finish machined.
4. State the testing and certification level. EN 10204 3.1 or 3.2, impact test temperature, UT acceptance class, any third-party witness points.
5. Review the quotation and forging drawing. We return a forging drawing showing machining allowance and test-prolongation positions for approval before cutting steel.
6. Production and release. Melting, forging, normalising, testing, machining, inspection release, then packing for sea or air freight.