How to weld Hastelloy C22, Hastelloy C22 to Carbon steel?

What is Hastelloy C22?

Hastelloy C22, also known as alloy C22, is a widely used austenitic nickel-chromium-molybdenum-tungsten alloy with improved resistance to various corrosion mechanisms such as pitting, crevice corrosion, and stress corrosion cracking. The high chromium content provides good resistance to oxidizing media while the molybdenum and tungsten content give good resistance to reducing media.

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Material Specifications

Pipe SmlsPipe WeldedTube SmlsTube WeldedSheet / PlateBarForgingFitting

Chemical composition of Hastelloy C22

Below table list the main chemical composition of Hastelloy C22. This is primarily alloyed with Ni & Mo.

.010 max20-22.52.5 max2.0-6.0.50 max12.5-14.5Balance.02 max.08 max.02 max2.5-3.5.35 max

Mechanical properties of Hastelloy C22

The typical mechanical properties of Hastelloy C22 at room temperature are given in the below table.

Product FormTensile (ksi).2% Yield (ksi)Elongation %Hardness (HRb)
Plate (.25”-1.75”)112536289
Sheet (.038”-.15”)122635493
Bar (.50”-5.50”)115556089

SMAW, GTAW & GMAW Welding of Hastelloy C22

Nickel-based alloys such as C22 generally exhibit sluggish welding and shallow penetration characteristics; therefore, the possibility of incomplete fusion increases. Care must be used to ensure a sound weld. If orbital or automatic welding equipment is used, use a pulsed current welding program. Pulsed current inputs can help control weld penetration without exclusive heat input. Pulsing also helps control the weld pool, improving the uniformity of weld bead appearance.

SMAW welding electrode for hastelloy C22

SMAW welding of Hastelloy C22 shall be carried out using SMAW electrode ENiCrMo-10 (AWS SFA 5.11). ENiCrMo-10 Can join stainless and nickel alloys or dissimilar corrosion-resistant alloys and cladding. It is suitable for most applications in the as-welded condition for use on Hastelloy C22. ENiCrMo-10 shall also be used to join Hastelloy C22 to carbon steel.

GTAW/TIG welding consumable for hastelloy C22

GTAW/TIG welding of Hastelloy C22 shall be weld using ERNiCrMo-10 type filler wire. ERNiCrMo-10 filler metal is used for the gas metal (MIG) and gas tungsten arc (TIG) welding of HASTELLOY C-22 alloy. The deposited weld metal has low thermal expansion characteristics, good oxidation resistance to 1500°F (815°C), and excellent fabricability. Backing gas (100% argon) should always be used for the root pass when welding by either GTAW or GMAW. For SMAW, grinding of the backside of the root pass is necessary.

The typical weld deposit chemistry of ERNiCrMo-10 is given in the below table.

C = 0.014Mn = 0.35Si = 0.16
Cr = 21.2Mo = 13.1W = 3.3
P = 0.012S = 0.005Fe = 3.9
Ni = Balance

Typical mechanical properties usually achieved using ERNiCrMo-10 are given in the below table for general reference. These values however can change based on welding heat input and other welding variables that might affect the mechanical properties of the deposited weld.

Tensile Strength113,000 psi
Yield Strength78,000 psi

Preheat & Interpass temperature

No preheating is required for Hastelloy C22 during welding as this is primarily an austenitic base alloy. controlling interpass temperatures, generally, 200°F (93°C) or less is recommended to control the phase balance. Post weld heat treatments are also not required for this alloy.

Recommended welding parameters for TIG welding

Below table gives the recommended welding parameters for TIG welding of Hastelloy C22.

Diameter of WireVoltage (V)Flat (Current in Amp)Vertical and Overhead (Current in Amp)
3/32 inches (2.4mm)24 – 2870 – 8565 – 75
1/8 inches (3.2mm)26 – 3085 – 11080 – 90
5/32 inches (4.0mm)28 – 32110 – 140100 – 120
3/16 inches (4.8mm)28 – 32120 – 160110 – 130

Welding of Hastelloy C22 to carbon steel & Stainless steel

Welding of hastelloy C22 to carbon steel and stainless steel such as SS316 shall be carried out using ENiCrMo-10 with SMAW or with ERNiCrMo-10 with TIG or MIG Welding. Pure argon shall be used for shielding and purging applications with TIG/ MIG welding. When welding with SMAW, root shall be cleaned properly to remove any remaining slag/ oxides which otherwise can hamper the corrosion resistance of the weld metal.

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