Section 10 — Material Requirements

Supplemental Material Requirements for Metallic Materials

IPE Engineering Practice IPE-EP-10-2-2

Document number: IPE-EP-10-2-2 · Section: 10 — Material Requirements

SCOPE

• This Practice covers supplemental requirements for metallic materials used for fabrication of equipment and piping. This Practice excludes atmospheric storage tanks.
• Any deviation from this Practice must be approved by the procedure described in EP 1–1–3.
• An asterisk (*) indicates that a decision by the Owner’s Engineer and the Owner is required, or that additional information is to be furnished by the Purchaser.

2.0 REFERENCES

The latest edition of the following standards and publications are referred to herein.

STANDARDS AND PUBLICATIONS

DEFINITIONS

• Carbon Equivalent (CE) - A measure of the hardenability of carbon steels based on the chemical composition. The lower the number, the lower the likelihood of forming hard heat affected zones during welding, which can result in delayed cracking or service induced cracking.

CE - %C + %Mn/6 + (%Cr + %Mo + %V)/5 + (%Ni + %Cu)/15

• J* and X–Factors which relate the quantity of residual elements to the degree of temper embrittlement for 2–1/4 Cr–1 Mo steel and in some cases for 1–1/4 Cr steels. Elements, such as P, Sn, Sb, and As, lead to temper embrittlement, and Si and Mn accelerate the rate of temper embrittlement.

J* = (%Mn + %Si) x (%P + %Sn) x 104 and

X = (10x %P + 5x %Sb + 4x %Sn + %As) x 100 (All % = wt.%)

• Quench and tempered (Q&T) and normalized and tempered (N&T) refer to the method of heat treatment used for the low Cr steels. Quenching is a faster (water) cooling rate than the slower normalizing (air) cooling.
• SEP cooling - A precise heat treatment procedure applied to a test sample of 2–1/4 Cr steel to simulate any temper embrittlement which could occur during service.
• Design Temperature - Shall be the highest temperature reached during operation, steam-out, or regeneration.
• Hot tensile test - A tensile test performed at the equipment design temperature.
• MDMT - Minimum Design Metal Temperature as defined in EP 7–1–1 and EP 5–1–1.

REQUIREMENTS FOR CARBON AND LOW ALLOY STEELS

• For carbon steels the maximum limits, as determined from the materials test report, for carbon and carbon equivalent (CE) and maximum limits of the micro–alloying elements Cb and V are provided in Table 1.
• Hardness requirements shall be in accordance with EP 10–2–3.
• Supplemental material requirements for pressure containing equipment and piping fabricated from Carbon Steel, 1–1/4 Cr and 2–1/4 Cr Steel are as stipulated in Table 2 .
• (*) So called “HIC resistant” steels (reduced sulfur content and calcium treated) shall not be used in wet H2S service without prior review and acceptance by Owner’s Engineer. A stringent pre-qualification test to ascertain resistance to through thickness cracking will need to be met for acceptance. The test may include welded and stressed specimens.
• When stipulated in Table 2, SEP Cooling in accordance with the following procedures shall be applied to 2–1/4 Cr-1 Mo Steels.
• SEP Cooling tests are required for:
• Each heat for plate, and lot for forgings

• Each lot of welding electrodes, each batch of flux and each heat of filler wire.
• Samples for testing shall be taken from the 1/4 thickness location.
• For welding wire or electrodes, test welds shall be made on plates or forgings of the alloy specified for the equipment, using the proposed welding procedures. The thickness of the test plate shall not be less than 2 inches and the test specimens shall be taken at mid thickness. These tests may be made by the welding consumable manufacturer.
• SEP cooling tests for weld metals shall meet the same requirements as the base metal.
• A SEP Cooling heat treatment shall be applied to the samples per the sEPs in Table 4 in chronological order.
• Charpy V–notch impact transition temperature curves shall be developed for both samples that were subjected to the SEP Cooling and that were not. A curve shall be developed plotting the average impact value of three specimens for each test temperature with a minimum of five (5) different test temperatures required for each curve.
• The acceptance criteria shall be the following where Cv Tr40 is the 40ft–lbs transition temperature before sEP cooling, and Sv Tr40 is the shift in the 40 ft–lbs transition temperature as a result of sEP–cooling.

Cv Tr40 + 3.0 x SCv Tr 40 = 75°F maximum

• (*) As specified in Table 2, X requirements for 1–1/4 Cr and 2–1/4 Cr are only required at a design temperature (DT) greater than 700°F and thicknesses greater than 1 inch. In addition, X requirements apply to all 1–1/4 Cr and 2–1/4 Cr FCCU reactor cyclones. Although creep

and temper embrittlement are not a function of thickness, the 1 inch cutoff arises from

availability concerns, particularly for small quantities. Therefore, for DT greater than 700°F, X should also be applied to thicknesses less than 1 inch, but if material is unavailable then this provision may be waived by Owner’s Engineer.

• When stipulated in Table 2, hot tensile tests shall be in accordance with the following requirements.
• Two tensile test specimens shall be taken from the transvere 1/4 thickness location of each head and shell plate. All forgings other than ASME/ANSI 16.5 or 16.47 flanges shall have two tensile test specimens taken from the forging prolongations of each forging lot. Separate test blocks or bars are unacceptable.

• The tensile specimens shall be given a simulated heat treatment equal to the actual heat treatment of the plate or forging plus the sequence of heat treatments equal to the total fabrication postweld heat treatment plus one additional heat treatment. In ordering materials for vessels subject to PWHT, the vessel manufacturer shall note that the total heat treatment and time may not be controlled by their own thickness, but rather by thicker components elsewhere in the vessel.
• The tensile tests shall be performed at the vessel design temperature. For vessels designed to the ASME Code, Section VIII, Division 1 or 2, the hot tensile test values for yield and tensile strength shall be those listed in Section II Part D at the design temperature. The actual stress values shall be given to the materials manufacturer.
• When stipulated in Table 2, Charpy Impact testing shall be in accordance with the ASME Code Section VIII (either Division 1 or Division 2, as applicable) and the following requirements.
• One set of Charpy V Notch (Cv) specimens shall be taken from each plate and piping lot. Each set shall consist of three specimens. The specimens shall be from the 1/4 thickness location.
• One set of Charpy V Notch (Cv) specimens shall be taken at the 1/4 thickness location from the prolongations of each nozzle size and forging lot. They shall be oriented normal to the direction of greatest elongation. The forging prolongation used for the test samples shall be equal to or exceed the thickness of the thickest portion of the subject forging.
• All sets of Charpy V Notch specimens shall be given the same simulated treatment sequence as the corresponding tensile test specimens as in paragraph 4.6 in this Practice.
• Impact testing requirements are as follows:
• For vessels constructed to the ASME Code, Section VIII, Division 1; impact testing requirements shall be per Paragraphs UG 84 and UCS–66 with the following exceptions:
• The exemption from impact testing for P1 Group 2 steels as given in Paragraph UG 20(f) of the ASME Section VIII Div. 1 Code, is not permitted.
• For 1 1/4 Cr and 2 1/4 Cr low alloy steels, the exemption curves in UCS–66 do not apply and impact testing is mandatory.
• The maximum thickness at welds for SA 285–C, SA 299, SA 455, and SA 515 Grades 65 and 70 shall be limited to less than 1/2 inch.
• SA 36 and SA 283 are not permitted for any pressure parts.
• Impact energy acceptance values for carbon and low alloy steels shall be per Table 2 .
• For vessels constructed to the ASME Code, Section VIII, Division 2; impact testing requirements shall be per Paragraphs AM 204, 211, 213, 214 and 218 with the following exceptions
• For 1 1/4 Cr and 2 1/4 Cr low alloy steels, the exemption curves for impact testing in AM 218 do not apply and impact testing is mandatory.
• Impact energy acceptance values for carbon and low alloy steels shall be per Table 2.
• The impact test temperature shall be the MDMT (minimum design metal temperature).
• The required impact strength values (ft–lbs) shall be per Table 2 .
• (*) If the chemical composition or test result values exceed the limits in this Practice, then the Owner’s Engineer must be consulted.

• (*) C–1/2 Mo Steel shall not be used, unless approved by Owner’s Engineer.

REQUIREMENTS FOR STAINLESS STEELS

• Austenitic stainless steels used in the construction of welded vessels and piping/piping components with a design temperature less than or equal to 800°F shall be the low carbon grades, AISI Types 304L or 316L, or stabilized grades, AISI Types 321 or 347. Dual stamped materials (304/304L) are acceptable. Austenitic stainless steels used above 800°F shall be subject to the approval of the Owner’s Engineer.
• The following are the heat treatment requirements for Type 321 stainless steel operating above 750°F.
• Type 321 stainless steel (SS) can sensitize when exposed to temperatures above 750°F for extended periods of time. Welding does not normally sensitize Type 321 SS. Once a material is sensitized it is susceptible to polythionic stress corrosion cracking (PSCC). Soda ash washing, per EP 10–2–1, may be effective in minimizing the risk of PSCC in most non–coking services, but it is difficult to properly apply the procedure. Therefore the goal is to impart as much sensitization resistance as possible by means of thermal treatment. The long–time sensitization resistance of Type 321 SS (welded or non–welded) can be greatly improved by a modification to the standard ASTM specification required solution annealing temperature or by a stabilization heat treatment following solution annealing.
• Field PWHT (Stabilization at 1625  25°F for 4 hrs) is required for all field welds for 321 SS operating above 850°F. The acceptable heat treatments for Type 321 SS are stipulated in Table 3.
• The required heat treatment procedure for 17–4 PH stainless steel commonly used for valve stems is given by NACE MR 01 75– Latest Revision.

6.0 REQUIREMENTS FOR HIGH ALLOY STEELS

(*) Grade 800 H (ASTM B 407/ 423/ 424/ 425/ 564) used above 900°F service shall have the grain size measured through–thickness and shall be grain size 5 or coarser. A photographic record of the grain size shall be made and available to the Owner’s Engineer for review. The grain size sampling frequency shall be specified by the Owner’s Engineer.

7.0 TABLES

TABLE 1

MAXIMUM LIMITS FOR CARBON EQUIVALENT AND MICROALLOYING CONTENT FOR CARBON STEEL

NOTES

• T is the plate thickness
• CE - Carbon Equivalent, Cb - Colombium content and V - Vanadium content.
• TMCP - Thermo–Mechanical Controlled Process Steel

TABLE 2

MATERIAL REQUIREMENTS FOR PRESSURE CONTAINING EQUIPMENT FABRICATED FROM CARBON STEEL AND LOW ALLOY STEEL

TABLE 2 (CONTINUED)

MATERIAL REQUIREMENTS FOR PRESSURE CONTAINING EQUIPMENT FABRICATED FROM CARBON STEEL AND LOW ALLOY STEEL

TABLE 2 (CONTINUED)

MATERIAL REQUIREMENTS FOR PRESSURE CONTAINING EQUIPMENT FABRICATED FROM CARBON STEEL AND LOW ALLOY STEEL

NOTES:

• Piping components include fittings, flanges and valves.
• Excludes flange forgings purchased in accordance with ASME B16.5 and B16.47.
• T - thickness defined per the applicable ASME Code.
• DT is defined in EP 7–1–1 or EP 5–1–1.
• The use above the maximum temperature requires approval by Owner’s Engineer.
• Owner’s Engineer approval required for service between 1100 and 1200°F.
• The same temperature limits also apply to 1/2 Cr to 9 Cr materials.
• An additional requirement is that the % shear for the Charpy specimens shall exceed 20%.
• Code Case 1960 enhanced–strength 2–1/4 Cr material shall not be used without approval by Owner's Engineer.
• This heat treatment does not apply to Code Case 1960 enhanced–strength 2–1/4 Cr material; heat treatment is governed by Code Case 1960.
• SEP cooling Impact Test Acceptance criteria are specified in paragraph 4.5.7

TABLE 3

ACCEPTABLE HEAT TREATMENTS FOR TYPE 321 SS OPERATING ABOVE 750°F (1)

NOTE:

• Either A or B heat treatment procedure in the above table is acceptable.
• Also applies to ASME Section II materials.

TABLE 4

TIME/TEMPERATURE CYCLE FOR SEP COOLING

© 2026 Inflection Point Engineering, LLC. All rights reserved.