TUTORIALS ON WELDING RODS
Welding Rod Info
1. The E7018 welding rods I've been buying are now marked E7018 H4R. What does the H4R mean? Are these rods different than the E7018 rods I've used before?
H4R is an optional supplementary designator, as defined in AWS A5.1-91 (Specification for shielded metal arc welding electrodes). Basically, the number after the "H" tells you the hydrogen level and the "R" means it's moisture resistant.
"H4" identifies electrodes meeting the requirements of 4ml average diffusible hydrogen content in 100g of deposited weld metal when tested in the "as-received" condition.
"R" identifies electrodes passing the absorbed moisture test after exposure to an environment of 80ºF(26.7ºC) and 80% relative humidity for a period of not less than 9 hours.
The H4R suffix is basically just additional information printed on the rod, and does not necessarily mean a change in an electrode previously marked E7018.
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2. Why is hydrogen a concern in welding?
Hydrogen contributes to delayed weld and/or heat affected zone cracking. Hydrogen combined with high residual stresses and crack-sensitive steel may result in cracking hours or days after the welding has been completed.
High strength steels, thick sections, and heavily restrained parts are more susceptible to hydrogen cracking. On these materials, we recommend using a low hydrogen process and consumable, and following proper preheat, interpass, and postheat procedures. Also, it is important to keep the weld joint free of oil, rust, paint, and moisture as they are sources of hydrogen.
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3. What is the maximum plate thickness which can be welded with Innershield® NR®-211-MP (E71T-11) wire?
NR®-211-MP is restricted to welding these maximum plate thicknesses:
Wire Diameter Maximum Plate Thickness
.030"(0.8mm) 5/16"(7.9mm)
.035"(0.9mm) 5/16"(7.9mm)
.045"(1.1mm) 5/16"(7.9mm)
.068"(1.7mm) 1/2"(12.7mm)
5/64"(2.0mm) 1/2"(12.7mm)
3/32"(2.4mm) 1/2"(12.7mm)
For thicker steels, look to Innershield® NR-212. It has similar welding characteristics to NR®-211-MP but is designed for use on materials up to 3/4" (19.1mm) thick.
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4. What electrode can I use to join mild steel to stainless steel?
Electrode selection is determined from the base metal chemistries and the percent weld admixture. The electrode should produce a weld deposit with a small amount of ferrite (3-5 FN) needed to prevent cracking. When the chemistries are not known, our Blue Max® 2100 electrode, which produces a high ferrite number, is commonly used.
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Welding Rod Info
1. The E7018 welding rods I've been buying are now marked E7018 H4R. What does the H4R mean? Are these rods different than the E7018 rods I've used before?
H4R is an optional supplementary designator, as defined in AWS A5.1-91 (Specification for shielded metal arc welding electrodes). Basically, the number after the "H" tells you the hydrogen level and the "R" means it's moisture resistant.
"H4" identifies electrodes meeting the requirements of 4ml average diffusible hydrogen content in 100g of deposited weld metal when tested in the "as-received" condition.
"R" identifies electrodes passing the absorbed moisture test after exposure to an environment of 80ºF(26.7ºC) and 80% relative humidity for a period of not less than 9 hours.
The H4R suffix is basically just additional information printed on the rod, and does not necessarily mean a change in an electrode previously marked E7018.
Back to Top
2. Why is hydrogen a concern in welding?
Hydrogen contributes to delayed weld and/or heat affected zone cracking. Hydrogen combined with high residual stresses and crack-sensitive steel may result in cracking hours or days after the welding has been completed.
High strength steels, thick sections, and heavily restrained parts are more susceptible to hydrogen cracking. On these materials, we recommend using a low hydrogen process and consumable, and following proper preheat, interpass, and postheat procedures. Also, it is important to keep the weld joint free of oil, rust, paint, and moisture as they are sources of hydrogen.
Back to Top
3. What is the maximum plate thickness which can be welded with Innershield® NR®-211-MP (E71T-11) wire?
NR®-211-MP is restricted to welding these maximum plate thicknesses:
Wire Diameter Maximum Plate Thickness
.030"(0.8mm) 5/16"(7.9mm)
.035"(0.9mm) 5/16"(7.9mm)
.045"(1.1mm) 5/16"(7.9mm)
.068"(1.7mm) 1/2"(12.7mm)
5/64"(2.0mm) 1/2"(12.7mm)
3/32"(2.4mm) 1/2"(12.7mm)
For thicker steels, look to Innershield® NR-212. It has similar welding characteristics to NR®-211-MP but is designed for use on materials up to 3/4" (19.1mm) thick.
Back to Top
4. What electrode can I use to join mild steel to stainless steel?
Electrode selection is determined from the base metal chemistries and the percent weld admixture. The electrode should produce a weld deposit with a small amount of ferrite (3-5 FN) needed to prevent cracking. When the chemistries are not known, our Blue Max® 2100 electrode, which produces a high ferrite number, is commonly used.
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