low hydrogen rod

[gwk]

what is the purpose of the use of a low hydrogen rod? does the low hydrogen content make it flow better?

[performance]

Hydrogen is an enemy of welding. Steel and hydrogen have an affinity for one another. The result is called Hydrogen embrittlement. The effect that you will normally see form hydrogen introduction into the weld is sudden failure or cracking.

Water as we all know is loaded with hydrogen. Moisture in certain rods causes a lot of issues, when the hydrogen is broken down into its elemental form through electrolysis via the welding arc, it will get trapped into the weld and cause problems.

7018's are considered low hydrogen due to their manufacturing technique and metal composition. These are exceptionally smooth welding rods capable of beautiful welds and are strongly joined.

However, lo-hi rods such as the 7018 are only truly low if they are kept from moisture and in a rod oven until they are ready to be used. Typically 7018's will only be low high for about 8 hours outside the oven.

The paper boxes and platic boxes that so many lo-hi rods come in are NOT designed to keep moisture out. Tedius prebaking and drying out of the rods must be done to restore the Lo-hi properties. I don't recommend buying them in this form...although they will weld fine, you don't get the lo-hi benefits. Buy only sealed metal cans. Typical rods like this are found in the Lincoln Excalibur series. Once the can is opened the rods must be used within 8-10 hours or put into a rod oven for long term storage.

A 7018 is a good choice for a beginner as it welds smooth and nearly as flawlessly as a 6013 or 7014 rod. But it can be difficult and like to stick from time to time as well.

[smackdaddy]

WHAT??? So 7018 used in pipeline welding is only for beginners??? Somebody is smoking crack or I need to start smoking it too make sense of this comment!

[matteh99]

Performance didn't say 7018 are only for beginners. He said that they are good for beginners.

I would say that he pointed out that they are best for experts because average joe's don't have rod ovens.

I have seen moisture resistance 7018 rods advertised but I haven't used them or talked to any one who has. I also don't know how moisture resistant they are.

Eric

[performance]

E7018-1 h4r is a very low hydrogen rod. The 4 is for the ml's of difussable (whatever that means...I believe it is referring to actual H20) hydrogen in 100 grams of weld metal, which is the lowest rating. The r is for moisture resistant.
A r rod is good for a 10 hour shift out of the oven or fresh from the can. A regular 7018 is good for only 2.

No, I wasn't trying to say a 7018 is for beginners only.

I was saying it is a good rod for a beginner to weld with. Even if he or she cannot provide a suitable storage environment for the rods... I.E. anything that comes from a box or plastic sleeve, will still be good to make good "looking" welds. The manipulation will remain basically the same whether the rod is dry or not. The only thing different will be the end strenth of the weld and the possibility of hydrogen cracking in the root of the weld.

[smackdaddy]

Ah thanks for clarifying. Guess I don't need to smoke crack now!