ERNiCrMo-4 vs ERNiCrMo-10: Differences, Applications and Selection Guide

In nickel-alloy welding, ERNiCrMo-4 and ERNiCrMo-10 are two widely used high-performance Ni-Cr-Mo filler wires. Both comply with AWS A5.14 and are commonly applied in chemical processing, marine engineering, pollution control, nuclear power, and other demanding service environments.

Although they share a similar alloy family, their differences in chromium, molybdenum, and tungsten content lead to distinct corrosion resistance characteristics. Understanding these differences is essential for selecting the correct filler metal and ensuring long-term weld performance.

This article provides a detailed comparison of ERNiCrMo-4 vs ERNiCrMo-10, including chemistry, corrosion behavior, applications, equivalent grades, and selection considerations.

ERNiCrMo-4 is the matching filler metal for Hastelloy C-276 (UNS N10276). With high molybdenum and tungsten content, it is specifically designed for excellent resistance to strongly reducing corrosive environments.

ERNiCrMo-10 corresponds to Hastelloy C-22 (UNS N06022) and is also known as Alloy 22 welding wire or C-22 filler wire. Developed with a higher chromium content and optimized Ni-Cr-Mo balance, it provides excellent resistance in both oxidizing and reducing environments.

The key difference between the two alloys is their corrosion resistance focus:

• ERNiCrMo-4: optimized for strongly reducing acids and chloride-containing environments.
• ERNiCrMo-10: designed for broader corrosion resistance in mixed and complex chemical conditions.

For engineers and purchasing teams, ERNiCrMo-4 and ERNiCrMo-10 may appear under different commercial or alloy designations.

Although these filler metals are sometimes considered alternatives, the correct choice should always be based on the base material, corrosion environment, and project requirements.

Although both wires belong to the Ni-Cr-Mo family, differences in key alloying elements significantly influence their corrosion performance.

The main compositional difference lies in the balance between chromium and molybdenum:

• ERNiCrMo-4 contains higher molybdenum, which improves resistance to localized corrosion such as pitting and crevice corrosion, especially in reducing environments.
• ERNiCrMo-10 contains higher chromium, which enhances passivation and provides better resistance to oxidizing media.

Rather than one alloy being universally superior, the difference in chemistry gives each filler metal its own application advantage.

From a mechanical standpoint, ERNiCrMo-4 and ERNiCrMo-10 provide comparable weld performance.

Both filler metals offer high tensile strength and good ductility. Therefore, mechanical properties are usually not the primary factor when selecting between ERNiCrMo-4 and ERNiCrMo-10. The final decision is mainly determined by corrosion requirements and base metal compatibility.

The primary difference between ERNiCrMo-4 and ERNiCrMo-10 lies in their corrosion resistance characteristics.

ERNiCrMo-4 (High Molybdenum C-276 Filler Metal)

• Excellent resistance to strongly reducing acids such as hydrochloric acid, sulfuric acid, and phosphoric acid
• Outstanding resistance to chloride-containing environments
• Excellent resistance to stress corrosion cracking
• Reliable performance in severe chemical processing applications

ERNiCrMo-10 (High Chromium C-22 Filler Metal)

• Excellent resistance to both oxidizing and reducing media
• Higher chromium content for improved passivation ability
• Strong resistance to pitting, crevice corrosion, and chloride attack
• Better stability in complex chemical environments

Selection Logic

The choice between ERNiCrMo-4 and ERNiCrMo-10 should be based on the actual service environment:

• Choose ERNiCrMo-4 when the application involves strongly reducing acids, especially hydrochloric acid, sulfuric acid, or chloride-rich reducing environments.
• Choose ERNiCrMo-10 when the application requires resistance to both oxidizing and reducing media, or when a broader corrosion resistance range is needed.

ERNiCrMo-4 Applications

ERNiCrMo-4 is commonly used in industries requiring excellent resistance to severe reducing corrosion environments:

• Chemical processing equipment, including hydrochloric acid tanks, reactors, and acid handling systems
• Sulfuric acid processing equipment
• Nuclear industry applications requiring high corrosion resistance
• Flue gas desulfurization (FGD) systems
• Pollution control equipment
• Marine and offshore equipment exposed to severe chloride environments

ERNiCrMo-10 Applications

ERNiCrMo-10 is widely used in applications involving mixed chemical environments and demanding corrosion conditions:

• Flue gas desulfurization (FGD) absorber towers and internal components
• Pharmaceutical and fine chemical processing equipment
• Chlorination systems and chloride-containing chemical equipment
• Geothermal and offshore applications
• High-purity chemical production equipment
• Dissimilar metal welding between nickel alloys and stainless steels

In dissimilar metal joining, both wires are frequently used as alternatives to one another. For example:

• Welding C‑22 to 316L stainless steel: ERNiCrMo‑10 is the matching filler, while ERNiCrMo‑4 may also be used as an alternate.
• Welding C‑276 to carbon steel: either ERNiCrMo‑4 or ERNiCrMo‑10 is acceptable.
• Welding Inconel 625 to Inconel 718: both have been successfully employed on 5‑mm‑thick plates.

Studies have shown that ERNiCrMo‑4 weldments exhibit superior impact toughness at both ambient and sub‑zero temperatures compared to ERNiCrMo‑10. In applications demanding high toughness, ERNiCrMo‑4 may therefore hold an edge.

ERNiCrMo-4 and ERNiCrMo-10 are both high-performance nickel-alloy filler metals, but they are designed for different service conditions.

• ERNiCrMo-4 is the preferred choice for Hastelloy C-276 welding and strongly reducing environments, where high molybdenum content provides excellent corrosion resistance.
• ERNiCrMo-10 is recommended for Hastelloy C-22 welding and complex corrosion environments, where higher chromium content provides broader resistance against oxidizing and reducing media.

In practice, filler metal selection should be based on the base alloy, service environment, and project requirements. Choosing the correct ERNiCrMo filler wire helps ensure reliable weld performance and long-term corrosion resistance.

1. Can ERNiCrMo-10 replace ERNiCrMo-4?

In some applications, ERNiCrMo-10 can be used as an alternative filler metal, especially when broader corrosion resistance is required. However, for Hastelloy C-276 base materials or specifications requiring ERNiCrMo-4 classification, ERNiCrMo-4 remains the preferred choice.

2. What is the difference between ERNiCrMo-4 and ERNiCrMo-10?

The main difference is their alloy balance. ERNiCrMo-4 contains higher molybdenum and tungsten content for superior performance in strongly reducing environments, while ERNiCrMo-10 contains higher chromium content for improved resistance in oxidizing and mixed corrosion conditions.

3. Is ERNiCrMo-4 the same as Hastelloy C-276 welding wire?

Yes. ERNiCrMo-4 is the AWS A5.14 filler metal classification commonly used for welding Hastelloy C-276 and is often referred to as C-276 welding wire.

4. Is ERNiCrMo-10 the same as Alloy 22 welding wire?

Yes. ERNiCrMo-10 corresponds to Hastelloy C-22 and is commonly known as Alloy 22 welding wire or C-22 filler wire.

5. Which filler wire should I choose: ERNiCrMo-4 or ERNiCrMo-10?

The selection depends on the base metal and service environment:

• For C-276 welding or strongly reducing chemical environments, choose ERNiCrMo-4.
• For C-22 welding or applications involving mixed oxidizing and reducing corrosion conditions, choose ERNiCrMo-10.