Which statement about the suffix in E7018-H4R is correct?

Which statement about the suffix in E7018-H4R is correct?

• A. The R denotes Moisture Resistance
• B. The R denotes roundness
• C. The R denotes reduction
• D. The R denotes resistance to heat

Answer: (A)

The suffix in this electrode designation communicates how hydrogen is controlled and how the electrode handles moisture. The H4 part sets a very low allowable diffusible hydrogen content in the weld metal (about 4 mL per 100 g), which helps prevent hydrogen cracking in sensitive steels. The R indicates moisture resistance—the coating and packaging are designed to resist moisture uptake so the electrode stays low-hydrogen during storage and use. That’s why this suffix is read as moisture resistance. The other options don’t fit AWS naming conventions for this electrode; roundness, reduction, or heat resistance aren’t what the R conveys here.

The suffix in this electrode designation communicates how hydrogen is controlled and how the electrode handles moisture. The H4 part sets a very low allowable diffusible hydrogen content in the weld metal (about 4 mL per 100 g), which helps prevent hydrogen cracking in sensitive steels. The R indicates moisture resistance—the coating and packaging are designed to resist moisture uptake so the electrode stays low-hydrogen during storage and use. That’s why this suffix is read as moisture resistance. The other options don’t fit AWS naming conventions for this electrode; roundness, reduction, or heat resistance aren’t what the R conveys here.