Why Simply Depositing Metal Doesn't Guarantee Effective Hardfacing!

In the realm of hardfacing and rebuilding work, merely depositing metal isn't sufficient to ensure a durable repair. The deposited metal must not only restore the part to its original dimensions but also meet the service conditions to which the part is exposed:

Impacts
Metal-to-metal wear
Abrasion
Erosion
Cavitation

Why Mild Steels Aren't Suitable for Hardfacing

Economical mild or low-carbon steels (grades CSA G40.21–44W, AISI 1020, ASTM A36, A516, etc.) are severely limited in their applications. Their low alloy element content and ferritic microstructure (<0.20% C) make them unsuitable for wear-prone environments:

Accelerated wear when sliding against hard steel
Rapid deterioration in abrasive or erosive environments

Why Alloys ER70S6/S-2, E70C-6, or E7018 Are Ineffective for Hardfacing

Filler metals like:

ER70S6/S-2
E70C-6
Low hydrogen electrodes E7018

➡️ Produce deposits with hardness and wear resistance often inferior to that of the base steel. ➡️ Their low carbon and alloy element composition limits their ability to harden post-welding, reducing wear resistance.

These filler metals primarily contain manganese and silicon added to deoxidize the weld pool but do not add significant wear resistance.

Result: Hardfacing with these alloys can result in lower wear resistance than the base metal.

Limitations of Deposits on Stronger Steels

When these alloys are used on high-wear-resistant steels such as:

AISI 1045
4140
AR400

➡️ The deposit's microstructure remains predominantly ferritic or slightly pearlitic, limiting deposited metal hardness. ➡️ Carbon enrichment is absent, preventing quenching effects during cooling after welding, significantly reducing deposit wear resistance.

How to Achieve Effective Hardfacing?

For a successful and durable repair, the choice of filler material should be based on a comprehensive analysis of the work situation:
✅ Base metal chemical composition
✅ Microstructure compatibility (base metal/weld deposit)
✅ Type of wear (impact, abrasion, corrosion)
✅ Working environment (heat, corrosion)
✅ Dilution effect
✅ Buttering layer if necessary
✅ Deposit thicknessConclusion: Choose the Right Alloy from the Start!

Effective hardfacing isn't just about depositing metal. A detailed analysis of the part, its service conditions, and metallurgical composition is essential to:
✔️ Extend the part's lifespan
✔️ Improve wear resistance
✔️ Optimize overall equipment performanceNeed help with your hardfacing projects?

If you're looking to enhance the wear resistance of your parts or optimize your hardfacing procedures, our experts are here to assist you!

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