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Incoloy 800H ASME Design Stress Tables

Allowable Design Stress (psi) - UNS N08810, SB-407 / SB-409 / SB-564

Allowable Design Stress (MPa) - UNS N08810, SB-407 / SB-409 / SB-564

Values consolidated from ASME Section II Part D 2023 edition Table 1A for SB-407 / SB-409 / SB-564 N08810. [verify exact values from current ASME Section II Part D edition that the project Material Specification References before any pressure-vessel or piping design calculation.]

How to Read and Apply the Table

The allowable stress from ASME Section II Part D Table 1A is the design-stress input to the pressure-vessel wall-thickness calculation under ASME Section VIII Division 1 paragraph UG-27 (cylindrical shells) or UG-32 (formed heads), or the piping wall-thickness calculation under ASME B31.3 paragraph 304.1. The application steps are:

1. Look up the allowable stress S at the design temperature for the selected product form and material specification (SB-407 for seamless pipe, SB-409 for plate, SB-564 for forgings).
2. Apply the longitudinal-joint quality factor E from ASME Section VIII Division 1 Table UW-12 (E = 1.0 for seamless or fully-radiographed welded products).
3. Compute wall thickness from the design pressure P, vessel ID R, allowable stress S, joint factor E and corrosion allowance per the relevant code formula.
4. Compare the design temperature against the upper temperature limit (800H is qualified to 815 deg C / 1500 deg F under ASME Section VIII Division 1).

Time-Independent vs Time-Dependent Design

Above approximately 1000 deg F (538 deg C) the allowable design stress for 800H is governed by creep-rupture behaviour rather than by short-term tensile yield. ASME Section II Part D applies the lesser of (a) 67 percent of the average creep-rupture strength at 100,000 hours and (b) 80 percent of the minimum stress to cause a creep rate of 0.01 percent per 1000 hours to set the allowable stress in the creep regime. The transition is visible in the table as a sharp drop in allowable stress between 1000 deg F and 1100 deg F.

For applications running 100,000 hours plus design life, the creep-rupture envelope of the parent heat (not the average) should be confirmed by the project metallurgist if the design margin to creep-rupture is small. See creep rupture strength for the full creep-rupture data.

External Pressure Charts (UG-28)

For external-pressure design under ASME Section VIII Division 1 paragraph UG-28, the relevant chart for 800H is Chart NFN-13 in ASME Section II Part D. The chart provides factor A and factor B values for cylindrical shells under external pressure across the design-temperature range. The maximum allowable external pressure is computed from factor B, the shell OD and the wall thickness per UG-28. [verify chart NFN-13 from current ASME edition.]

Related References

For the chemistry and mechanical-property envelope that drives these design-stress values, see the consolidated data sheet. For high-temperature strength behaviour, see high-temperature strength. For the 800HT design-stress extension to 1800 deg F, see the 800 vs 800H vs 800HT comparison. For ASME Section VIII pressure-vessel applications, see ASME VIII pressure vessels. Companion product forms: seamless pipe, plate, forgings.

Design Stress FAQ

Q. Which ASME Section II Part D edition should I use for a new design project?
Use the edition that the project Material Specification References. Most refinery and petrochemical projects today reference the ASME 2023 edition or the 2025 addenda. Confirm with the project material engineer before any final wall-thickness calculation.

Q. What is the maximum design temperature for 800H under ASME Section VIII Division 1?
815 deg C (1500 deg F) is the upper temperature limit listed in ASME Section II Part D Table 1A for SB-407 / SB-409 / SB-564 N08810. For sustained service above 815 deg C, ASME Section VIII calls for the 800HT (UNS N08811) grade per SB-407 / SB-409 / SB-564 N08811, which extends the design-stress table to 1800 deg F (982 deg C).

Q. Can I use 800H design stress values for the welded pipe SB-514?
Yes for the parent metal allowable. ASME Section VIII Division 1 then applies the longitudinal-joint quality factor E from Table UW-12 to the SB-514 welded pipe. E = 1.0 applies for fully-radiographed seam (default on TorqBolt SB-514 production); E = 0.85 applies for spot-radiographed seam.

Q. Where does the design-stress drop from 1000 deg F (13,800 psi) to 1100 deg F (11,500 psi) come from?
The drop is the start of the creep-rupture-governed region. Below 1000 deg F the allowable is set by short-term tensile properties (smaller of 1/3.5 UTS or 2/3 yield). Above 1000 deg F creep-rupture starts to control the allowable; ASME applies the 67 percent of average 100,000-hour creep-rupture rule and the curve drops sharply.

Q. Is 800H code-qualified for ASME B31.3 process piping at 815 deg C?
Yes. ASME B31.3 Table A-1 lists UNS N08810 for SB-407 seamless pipe with allowable stress values matching the Section II Part D Table 1A entry from 100 deg F to 1500 deg F. The max design temperature for 800H under B31.3 is 815 deg C, same as Section VIII.

Request a Project-Specific Design-Stress Lookup

For a project-specific design-stress lookup at a non-tabulated temperature, or for the matching creep-rupture data at the specified design life (10,000 / 100,000 / 200,000 hours), contact the TorqBolt sales desk with the design temperature, design pressure, product form and design life.