Material group, thickness limits, minimum design metal temperature without impact testing, and Charpy requirements for tank plate — API 650 Section 4
◉ API 650 11TH ED. (JUNE 2007) WITH ADDENDA THROUGH ADDENDUM 3 · EFFECTIVE 1 FEB 2012 · NOT A REGULATORY SUBMISSION TOOL
⚠ Indicative tool only. Source: API 650 Section 4 (Materials) as supplied — the revision bars on the pages read 07, 08, 09 and 11, i.e. the 11th Edition as amended through Addendum 3, effective 1 February 2012 per your note. Later editions restructured Section 4, so do not assume these tables carry over. Every value was read from the page images. The Table 4-3 equations were checked against the values printed on Figure 4-1a itself (for example −12°C at 6 mm for Group I, −23.55°C at 13 mm for Group II, and −24°C at 40 mm for Group VI), against the USC table at every paired breakpoint (within 0.6°C — the two tables use API's own rounded thickness equivalents such as 40 mm for 1.5 in, so they are not exact conversions of each other between breakpoints and can differ by a couple of degrees there), and for continuity where ranges meet; the Table 4-5 energies agree between joules and ft·lbf.
Not included (not among the pages supplied): Section 5 including the allowable-stress Table 5-2, the rules for establishing the design metal temperature, Figure 4-2 (isothermal map), Appendix N (new materials), the nozzle/flange governing-thickness rules (§4.5.4, Figure 4-3), and piping, forging and bolting materials. This is a screening check; the Purchaser's data sheet and the edition governing your project control.
Identification
Research entries stay private to you for practice/testing. Switch to Official once this is a real design your company should see.
Material & Plate
Pick the row that matches how the plate is actually supplied — e.g. A 516M-415 appears in Group III (as-rolled) and Group IIIA (normalized, note 9), and the group drives the DMT curve. Thickness for the DMT curve is thickness including corrosion allowance. Pre-ticked Group VI plate types (A 537M Class 2, A 678M, A 841M) are assumed quenched-and-tempered or TMCP from their ASTM specifications, which the API table does not state — untick only if your plate is normalized.
Assessment Not evaluated
Check
Result
Minimum Design Metal Temperature Without Impact Testing (Figure 4-1 / Table 4-3)
Curves are drawn from the Table 4-3 linear equations. Your point is plotted at thickness including corrosion allowance. Groups IIA and VIA are for pipe and flanges (§4.5.4) and are shown for reference.
Charpy Test Acceptance (§4.2.9.3 – 4.2.9.6) Not evaluated
Full-size minimum comes from Table 4-5 for the material above. Subsize specimens are checked against the proportional value (§4.2.9.6). Rule (§4.2.9.3): the average of three must meet the minimum, with no more than one value below it and none below two-thirds of it; otherwise three retest specimens are taken and each must meet the minimum.
National-Standard Plate (§4.2.6, Table 4-2) — e.g. IS 2062
Plates to a recognised national standard are acceptable, with Purchaser approval, if they lie within the mechanical and chemical limits of one of the three grades in Table 4-2. Enter the limits of the candidate standard at the thickness of interest (yield often steps down with thickness). Blank fields are reported as not verified rather than assumed. Footnotes: semi-killed or fully killed, as-rolled or TMCP (20 mm maximum when TMCP replaces normalizing) or normalized; Grade 235 non-rimming only; yield ÷ tensile ≤ 0.75 on minimum specified values.
Grade
Tensile min
Tensile max
Yield min
Thickness
C heat
C product
P,S heat
P,S product
Yield/tensile ≤ 0.75
Result
General Provisions Worth Knowing
Materials generally (§4.1). Rimmed or capped steel is not permitted; cast iron is prohibited for any pressure part or part welded to the tank; cadmium-plated components need the Purchaser's consent. Materials outside the listed specifications may be used only if they meet every requirement of an applicable listed specification and the Purchaser approves; unidentified new or unused plate or pipe must pass the Appendix N tests. Substituting Group IV–VI plate for Group I–IIIA plate requires the Purchaser's prior written approval and keeping all design, fabrication, erection and inspection requirements of the lower-stress group (§4.1.5).
Plates (§4.2). Plate may be ordered by edge thickness or by weight; an underrun of up to 0.3 mm (0.01 in) from the computed design or minimum thickness is acceptable (§4.2.1.2). Shell plate is limited to 45 mm (1.75 in) unless a lesser limit applies; inserts and flanges may be thicker (§4.2.1.4). Above 40 mm (1.5 in) plates must be normalized or quenched-and-tempered, killed, fine-grain and impact tested; TMCP plate may substitute with Purchaser approval, each plate as-rolled tested (§4.2.10.1–.2). Where a specification limits manganese below 1.60%, the producer may raise it to 1.60% if carbon is cut to 0.20% maximum — marked “Mod” (§4.2.7.4). Group VI and ISO E355 are also limited to the alloy contents of Table 4-1 (heat analysis, %): Nb 0.05, V 0.10, Nb+V 0.10, N 0.015, Cu 0.35, Ni 0.50, Cr 0.25, Mo 0.08. Reinforcing and insert plates match the shell plate or any appropriate Table 4-4 material of equal or greater yield and tensile strength (§4.2.10.4); roof nozzles and manholes need no special toughness (§4.2.10.5).
Sheets and shapes. Roof sheets: ASTM A 1011M Grade 33 (§4.3). Structural shapes (§4.4.1): A 36M, A 131M, A 992M, AISC-listed structural steels, CSA G40.21 (260W, 300W, 350W and T grades), ISO 630 E 275 (B, C, D), EN 10025 S 275 (JR, J0, J2), or a national standard meeting Table 4-2 with Purchaser approval.
Note on other lists. ASTM A 283 Grade D is not listed in §4.2.2 — only Grade C, to 25 mm.