Pressure vessel quality steel plate

01

Pick the grade and check yield at your thickness

U.S. Steel Košice, a flat steel producer, lists for EN 10028-2 minimum upper yield strength, tensile range and elongation of P235GH 235 MPa, 360–480 MPa, 24%; P265GH 265 MPa, 410–530 MPa, 22%; P295GH 295 MPa, 460–580 MPa, 21%; and P355GH 355 MPa, 510–650 MPa, 20%, each with a minimum Charpy V-notch energy of 27 J at −20 °C. [1]

Arvedi, an Italian steelmaker, gives the same room-temperature values and adds the minimum yield above 16 mm nominal thickness: 225, 255, 290 and 345 MPa respectively. It lists minimum impact energy of 40 J at 20 °C, 34 J at 0 °C and 27 J at −20 °C for all four grades, and cross-references P265GH to ASTM A516 Gr 60 and P355GH to JIS SPV 36. [2] Editorial note: a cross-reference table shows similar grades, not interchangeable ones; the vessel code decides which material is accepted.

Both producers list chemical limits, for example P265GH with carbon of 0.20% max and manganese 0.80–1.40%, and P355GH with carbon 0.10–0.22% and manganese 1.10–1.70%. [1] [2] Their published dimensions are for hot-rolled strip and sheet, up to 12.70 mm at U.S. Steel Košice and 10.75 mm for P265GH at Arvedi; ask plate mills for heavier thicknesses. [1] [2]

Salzgitter Flachstahl's table maps the EN 10028-2 grades to older and foreign designations, for example P235GH (1.0345) to ASTM A285 Gr. C, A414 Gr. C and A516 Gr. 55, P265GH (1.0425) to A516 Gr. 60, P295GH (1.0481) to A516 Gr. 65 and P355GH (1.0473) to A414 Gr. G and JIS SPV 36. It adds residual limits that apply to these grades — Cu up to 0.30%, Cr + Cu + Mo + Ni up to 0.70% and Al/N at least 2 — and notes that a minimum of 0.80% Cr may be agreed where resistance to high-pressure hydrogen matters. Treat the cross-references as a guide to equivalent grades, not as interchangeable certification. [3]

The ASTM grades named as cross-references are defined differently. ASTM A516/A516M-17 covers carbon steel plates "intended primarily for service in welded pressure vessels where improved notch toughness is important", in four grades named by tensile strength: Grade 55 [380] at 55–75 ksi [380–515 MPa], Grade 60 [415] at 60–80 ksi [415–550 MPa], Grade 65 [450] at 65–85 ksi [450–585 MPa] and Grade 70 [485] at 70–90 ksi [485–620 MPa]. The steel must be killed and fine austenitic grain, and the maximum plate thickness is limited only by the ability of the composition to meet the mechanical properties. The scope warns that inch-pound and SI values are not exact equivalents and must be used independently. [4]

Give the supplier the standard and grade (and the vessel code), thickness, width and length, quantity, delivery condition, impact test temperature, elevated-temperature proof stress testing if needed, ultrasonic testing class, surface and flatness requirements, and the inspection certificate type.

02

Check strength at the design temperature

U.S. Steel Košice lists minimum 0.2% proof strength at elevated temperature for the EN 10028-2 grades; for P355GH it is 343 MPa at 50 °C, 323 at 100 °C, 299 at 150 °C, 275 at 200 °C, 252 at 250 °C, 232 at 300 °C, 214 at 350 °C and 202 MPa at 400 °C, and for P265GH 256 MPa at 50 °C falling to 150 MPa at 400 °C. Testing at the agreed temperature must be agreed at enquiry and order. [1]

Arvedi's table gives the same values for 16 mm and under and slightly lower values above 16 mm, for example P355GH 334 MPa at 50 °C and 196 MPa at 400 °C. [2] Arvedi's table lists 105 MPa for P265GH at 200 °C at 16 mm and under, out of line with its neighbouring cells (215 MPa at 150 °C above 16 mm, 197 MPa at 200 °C above 16 mm) [2]; U.S. Steel Košice lists 205 MPa for the same case [1]. Confirm the figure with the mill.

Editorial calculation: P355GH's minimum proof strength at 400 °C (202 MPa) is about 41% below its 50 °C value (343 MPa); the design stress your code allows at temperature is derived from these elevated-temperature values, so state the design temperature in the enquiry. [1]

For service above 400 °C the same table continues with the molybdenum and chromium-molybdenum grades of EN 10028-2: 16Mo3 has a minimum 0.2% proof strength of 159 MPa at 400 °C and 141 MPa at 500 °C (16 mm and under), and 13CrMo4-5 has 186 and 164 MPa, while the carbon grades stop at 400 °C. Impact energy for P235GH to P355GH is 40 J at +20 °C, 34 J at 0 °C and 27 J at −20 °C, as an average of three samples with one value allowed up to 30% lower. [3]

03

Steel suppliers listing vessel plate beside carbon, shipbuilding and wear plate

Listings include pressure vessel steel plate alongside carbon, shipbuilding and wear-resistant plate from steel suppliers.

04

Grade, chemistry, yield by thickness, proof strength at temperature, impact energy and size

Yield by thickness and proof strength at temperature are the two rows that move with your design: minimum yield drops above 16 mm, and P355GH's proof strength is 202 MPa at 400 °C against 343 MPa at 50 °C. [2] [1]

05

Equivalent grade, thickness, yield, impact temperature and design temperature for a plate order

The equivalent-grade row needs care: Salzgitter's cross-reference pairs P265GH with A516 Gr. 60, yet the A516 tensile range starts 5 MPa higher, so name the standard the mill is to certify. [3] [4] [1]

06

Send the grade, size and testing data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Grade: [EN 10028-2 grade; ASTM equivalent; vessel code]
Size: [thickness; width; length; quantity]
Properties: [yield at thickness; impact temperature]
Temperature: [design temperature; proof testing]
Inspection: [certificate type; ultrasonic testing]
Delivery: [condition; surface; flatness]

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