Specifications
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
Incoloy 800H Weldability and Welding Procedures
Incoloy 800H (UNS N08810, Werkstoff 1.4876) welds readily by GTAW (gas tungsten arc welding), GMAW (gas metal arc welding), SAW (submerged arc welding) and SMAW (shielded metal arc welding) when matched with the correct nickel-base filler metal and run within a tightly controlled heat-input window. The alloy is fully austenitic and is therefore prone to weld-metal hot-cracking if Si, P or S residuals are high or if heat input is excessive; mitigation runs through three independent levers - low-residual filler, low-heat-input weld parameters, and stringer-bead technique with interpass cooling to below 175 deg C. Preheat is not required for 800H. Post-weld heat treatment is not required by ASME Section VIII for routine pressure-vessel service, but a full solution anneal at 2050 deg F (1121 deg C) followed by accelerated cool is supplied on call-out for fabrications that need the maximum long-term creep performance restored in the HAZ. This page summarises filler selection per process, parameter envelopes, preheat / interpass / PWHT requirements and the hot-cracking-mitigation procedures TorqBolt applies in the Rajkot fabrication shop for 800H welded assemblies under ASME Section IX qualified procedures.
Filler Metal Selection (AWS A5.14 + AWS A5.11)
| Welding process | Default filler | AWS spec | Service notes |
|---|---|---|---|
| GTAW (TIG) | ERNiCrFe-2 | AWS A5.14 | Ni-Cr-Fe with Nb stabilisation; standard for 800H to 800H, 800H to 304/316 stainless, 800H to Inconel 600 |
| GTAW (TIG) - reducing service | ERNiCrFe-7 | AWS A5.14 | Nb-stabilised; used for service in strongly reducing or carburising environments |
| GMAW (MIG) | ERNiCrFe-2 | AWS A5.14 | Pulsed-spray transfer; argon + 1 to 5 percent CO2 or argon-helium shield |
| SAW | ERNiCrFe-2 wire + matching flux | AWS A5.14 + A5.17 | Used for longitudinal seam on SB-514 welded pipe and large-diameter shell-side fabrication |
| SMAW (stick) | ENiCrFe-2 or ENiCrFe-3 | AWS A5.11 | For field repair, positional work, restricted-access locations; AC or DCEP |
Welding Parameter Envelope (per Process)
| Process | Current | Voltage | Travel speed | Shielding |
|---|---|---|---|---|
| GTAW (root + fill, manual) | 80 to 220 A DCEN | 10 to 16 V | 50 to 150 mm/min | Pure argon (99.99 percent), 8 to 12 L/min |
| GTAW (orbital, root pass) | 40 to 120 A DCEN | 10 to 14 V | per orbital head program | Argon |
| GMAW (pulsed spray) | 120 to 200 A DCEP | 22 to 28 V | 200 to 400 mm/min | Argon + 1 to 5 percent CO2 OR argon-helium |
| SAW | 300 to 600 A DCEP | 28 to 34 V | 300 to 600 mm/min | Matching neutral or basic flux |
| SMAW | 70 to 140 A DCEP | 22 to 26 V | per electrode size | n/a |
Heat input is targeted at 1.0 to 2.0 kJ/mm to limit grain coarsening in the HAZ. Above 2.5 kJ/mm the HAZ grain coarsens excessively and creep performance in service degrades.
Preheat, Interpass and PWHT
- Preheat: Not required. Ambient (above 15 deg C) is acceptable. Pre-heat to 50 to 100 deg C is supplied only to drive off surface moisture on heavy section parts.
- Interpass temperature: 175 deg C (350 deg F) maximum. Allow each weld pass to cool below the interpass limit before starting the next pass. Air-cool or use a temperature-indicating crayon to confirm.
- PWHT - routine: Not required for ASME Section VIII routine service. Welded assemblies are placed in service as-welded with no PWHT.
- PWHT - call-out (creep service): Full solution anneal at 2050 deg F (1121 deg C) + accelerated cool, for fabrications that need HAZ creep performance fully restored. Typical for centrifugally-cast-to-wrought joints in ethylene cracker furnaces.
- PWHT - call-out (sensitisation): A stabilising anneal at 870 to 900 deg C for 1 hour per 25 mm followed by slow furnace cool is supplied where the welded assembly will be subjected to service in the sensitisation temperature window (600 to 800 deg C) and the HAZ chromium carbide precipitation needs to be re-dissolved.
Hot-Cracking Susceptibility and Mitigation
Fully austenitic 800H weld metal solidifies as primary austenite with no delta-ferrite to absorb segregation, so hot-cracking risk is real but manageable. The three independent mitigation levers are:
- Low-residual filler: Specify ERNiCrFe-2 with S below 0.010 percent, P below 0.010 percent and Si below 0.50 percent. Filler-metal heat-batch certs should be retained.
- Low-heat-input parameters: Heat input 1.0 to 2.0 kJ/mm; stringer-bead technique with maximum oscillation amplitude 2.5 x electrode diameter; avoid weave.
- Joint design for shrinkage: Single-V bevel at 30 deg with 1.6 mm root face; backing where possible; avoid restrained joints; finger-bead the root pass.
Dissimilar-Metal Welds
| 800H to ... | Filler | Service notes |
|---|---|---|
| 800H to 800H | ERNiCrFe-2 | Matching nickel-base filler |
| 800H to 304/316/321 stainless | ERNiCrFe-2 or ER309L | ER309L for service below 540 deg C; ERNiCrFe-2 for higher temperature |
| 800H to Inconel 600 / 601 | ERNiCr-3 or ERNiCrFe-7 | Inconel 82 filler (ERNiCr-3) gives full strength match |
| 800H to carbon steel | ERNiCrFe-2 with butter layer of ERNi-1 | Butter layer on carbon-steel side to control carbon migration |
| 800H to chrome-moly (P22 / P91) | ENiCrFe-3 or ERNiCr-3 with butter layer | Butter chrome-moly side first, anneal, then complete the joint |
ASME Section IX Qualified Procedures Available
TorqBolt holds the following ASME Section IX qualified WPS and PQR records for routine 800H fabrication:
- WPS / PQR GTAW: 800H to 800H, all positions, t = 3 to 25 mm, ERNiCrFe-2.
- WPS / PQR GTAW + SMAW: 800H to 800H, root + fill, t = 6 to 50 mm, ERNiCrFe-2 + ENiCrFe-3.
- WPS / PQR SAW: 800H to 800H longitudinal seam (for SB-514 welded pipe), t = 5 to 25 mm, ERNiCrFe-2 + matching neutral flux.
- WPS / PQR GTAW + GMAW: 800H to 800H, 1G + 5G positions, t = 3 to 50 mm.
- WPS / PQR GTAW: 800H to centrifugally cast 800H (HK40 / HP-modified), t = 8 to 50 mm.
- WPS / PQR GTAW: 800H to 304L / 316L stainless dissimilar-metal joint.
Related References
Parent material data: data sheet, chemical composition, mechanical properties, heat treatment. Product forms typically welded: seamless pipe, welded pipe, plate, fittings, flanges. For design-stress impact of welded vs seamless construction, see ASME design stress tables.
Weldability FAQ
Q. Do I need to preheat 800H before welding?
No. Preheat is not required for 800H. Welding at ambient (above 15 deg C) is the standard. A light pre-heat to 50 to 100 deg C is supplied only to remove surface moisture on heavy sections after weather exposure.
Q. What is the maximum interpass temperature on 800H?
175 deg C (350 deg F). Above this limit the cumulative heat input grows the HAZ grain and degrades creep performance in long-term service. Use a temperature-indicating crayon between passes; do not start the next pass until the previous pass has cooled below the interpass limit.
Q. When is post-weld solution anneal at 2050 deg F required?
For routine ASME Section VIII pressure-vessel service, no post-weld solution anneal is required and the assembly is placed in service as-welded. For fabrications that need maximum long-term creep performance restored in the HAZ - typically ethylene cracker furnaces, primary-reformer outlet manifolds, and centrifugally-cast-to-wrought joints - a full solution anneal at 2050 deg F + accelerated cool is supplied on call-out per ASTM B407 / B564.
Q. Can I weld 800H to centrifugally cast 800H?
Yes. The joint between wrought 800H pipe / fitting and centrifugally cast 800H (HK40, HP-modified or 32-21 grades per ASTM A608) is welded with ERNiCrFe-2 filler under a qualified procedure. Standard practice is to butter the cast-side bevel with one pass of filler, dress flush, then complete the joint with stringer-bead fill. Hot-cracking risk is highest in this joint type so heat input and interpass are tightly controlled.
Q. What filler do I use for an 800H to Inconel 625 dissimilar joint?
ERNiCrMo-3 (Inconel 625 matching filler) is the standard for 800H to Inconel 625 dissimilar joints. The Mo content of the Inconel 625 filler delivers chloride pitting and crevice corrosion resistance on the wetted side; the Ni-Cr-Fe base of the 800H parent maintains creep performance on the high-temperature side.
Request a Project WPS / PQR
For a project-specific Welding Procedure Specification (WPS) and Procedure Qualification Record (PQR) on 800H to 800H, dissimilar-metal or cast-to-wrought joints, contact the TorqBolt sales desk with the joint configuration, plate / pipe / fitting size, position, process, filler classification and any project-specific PWHT requirement.
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