Understanding 7018 !!!

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As I understand it, the benefits of 7018 rods is that since they are low hydrogen this rod does something to the weld/parent metal that lets the metal gain some ductile ability.All this is provided that the rods are fresh out of the box or used out of a rod oven.Could some of you elaborate on this?
Reply:Originally Posted by rahtreelimbsAll this is provided that the rods are fresh out of the box or used out of a rod oven.Could some of you elaborate on this?
Reply:Hydrogen is the smallest molecule. They fit between metal molecules to interfere with crystal formation. Carl demonstrates all this is unimportant.An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.
Reply:Originally Posted by rahtreelimbsAs I understand it, the benefits of 7018 rods is that since they are low hydrogen this rod does something to the weld/parent metal that lets the metal gain some ductile ability.All this is provided that the rods are fresh out of the box or used out of a rod oven.Could some of you elaborate on this?
Reply:There is a nearly unlimited amount of reading available on the subject, here is a recent article.http://www.nxtbook.com/nxtbooks/aws/.../index.php#/30Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:i have darn near 50lbs each of 3/32" 7018 and 1/8" for just in case stuff.found out the other day that the bin i store them in is prone to moisture/ condensation and everything in there was visibly wet!they have already rusted, if you knock the flux off the rod has bits of rust full-length.no pics but they run fine! no porosity at startup or anything!im not saying go out and make a hoist with them, but just for the sake of welding, they weld without having a fancy oven. and if you think about it, under most circumstances, the rod is too hot to touch with a gloved hand by the time you are 1/4 of the way through it so the majority of your weld is dry no matter what. you can do the same thing by shorting the rod and waiting till no more steam comes off + 10 seconds . . ."one-at-a-time-oven"the filler itself is fairly ductile. a good example is to tack with it, and you are able to adjust your fitup quite a bit before the tack breaks. try it with 6010 and you will see how "brittle" it is in comparison.bosses stuff:trailblazer 325maxstar 200my stuff:sa 200fronius transpocket 180100 amp Lincoln w/f97 f350 DITKevin
Reply:They welded Liberty Ships long before 7018, and for the most part (some joint design issues, not filler metal issues) they held together.This rod, like any other rod that has an admixture when run, coupled with the alloy, does indeed make a ductile weld.  It's not solely a function of the parent metal, it's a function of the filler material alloy.The oven ****, is just that...............****.  It makes perfectly good welds as long as it's not soaked with water.  And as long as it doesn't run porous.  Code work is another matter though.  Mostly beyond what you see here on this site.  Most of the stuff you see here is pretty non-crucial."Any day above ground is a good day"http://www.farmersamm.com/
Reply:Originally Posted by MinnesotaDaveThere is a nearly unlimited amount of reading available on the subject . . .
Reply:Originally Posted by denrepyou can say that again; be sure the source is reliable.A random  interweb comment i just stumbled into while watching an antique electrode unboxing video. Thought y'all might like to see it.
Reply:nice find denrep. wonder what position your supposed to run 7018 anyway? i guess since my rod bin is moisture prone i need to see if i can find some 7070 to prevent that galvanic corrosion and whatnotbosses stuff:trailblazer 325maxstar 200my stuff:sa 200fronius transpocket 180100 amp Lincoln w/f97 f350 DITKevin
Reply:Originally Posted by denrepYou can say that again; be sure the source is reliable.
Reply:Originally Posted by 92dlxmannice find denrep. wonder what position your supposed to run 7018 anyway? i guess since my rod bin is moisture prone i need to see if i can find some 7070 to prevent that galvanic corrosion and whatnot
Reply:Back in the old days, they used to teach that:7018 was designed to limit underbead cracking which can be encouraged when a relatively hard steel (with alloy such as chrome moly, or with a high carbon content) is welded in a situation where there is excess hydrogen present, especially when it is done where a great deal of stress is present.So, If you are welding steel with high carbon or moly, you have one factor present.If you have excess moisture in the flux, on the steel, or in the atmosphere, you have another present.If you are welding cold, hard steel with insufficient preheat, or maybe two fixed pieces where shrinkage of the weld can not be accommodated, you have the third factor.This does not mean underbead cracking will always occur under these circumstances, and you obviously cannot eliminate all three factors, but you control what you can, in order to mitigate the risk.Maybe only a small percentage  of welds will catastrophically fail due to this issue, but when you are talking about chemical plants across the nation, and the number of welds represented, a small percentage of failed welds can cause a lot of deaths.Welding mild steel does not require 7018, as it is not a high risk for underbead cracking caused by the above three factors.So, I would think (opinion), that moisture content has no effect on 7018 welds made on mild steel, other than issues common to moisture content in any other rod, 6013, 6011, etc.(another opinion)You may be introducing more heat into a weld than is necessary, or is advised by using 7018 on 60,000psi steel, since it requires more heat to run properly, and that could present its own issues, under the right circumstances.Be advised I am old, remember little of importance, and mis-remember most of the other stuff.Last edited by geezerbill; 01-06-2015 at 10:34 AM.Hobart Beta-Mig 2511972 Miller AEAD-200LEMiller 250 TwinNorthern Ind. Hybrid 200Longevity Stick 140Longevity Migweld 200SThermal Arc Pak 3XR
Reply:Originally Posted by geezerbill(another opinion)You may be introducing more heat into a weld than is necessary, or is advised by using 7018 on 60,000psi steel, since it requires more heat to run properly, and that could present its own issues, under the right circumstances.Be advised I am old, remember little of importance, and mis-remember most of the other stuff.
Reply:Originally Posted by 92dlxman I guess since my rod bin is moisture prone i need to see if i can find some 7070 to prevent that galvanic corrosion and whatnot
Reply:Originally Posted by MinnesotaDaveI would tend to disagree since 1/8" 7018 and 7014 share the same amperage range in general.Overall I tend to agree with you on most stuff though
Reply:Originally Posted by farmersammThey welded Liberty Ships long before 7018, and for the most part (some joint design issues, not filler metal issues) they held together.This rod, like any other rod that has an admixture when run, coupled with the alloy, does indeed make a ductile weld.  It's not solely a function of the parent metal, it's a function of the filler material alloy.The oven ****, is just that...............****.  It makes perfectly good welds as long as it's not soaked with water.  And as long as it doesn't run porous.  Code work is another matter though.  Mostly beyond what you see here on this site.  Most of the stuff you see here is pretty non-crucial.
Reply:Originally Posted by geezerbillBack in the old days...............Be advised I am old, remember little of importance, and mis-remember most of the other stuff.
Reply:Originally Posted by Willie BUh... Sam.... Aren't Liberty Ships the ones that kept sinking before the torpedoes got to them?
Reply:Saved a few lives anyway.30+ yrs Army Infantry & Field Artillery, 25 yrs agoMiller 350LX Tig Runner TA 210, spool gunLincoln 250/250 IdealArcESAB PCM 500i PlasmaKazoo 30"  vert BSKazoo 9x16 horiz BSClausing 12x24 lathe20T Air Press
Reply:Originally Posted by docwelderthe liberty ship schenectady. Split apart in the yard (swan island,oregon) while under construction in 1943. This was that yards first liberty ship.
Reply:Originally Posted by docwelderthe liberty ship schenectady. split apart in the yard (swan island,oregon) while under construction in 1943. this was that yards first liberty ship.
Reply:Really? Again? How many times do we have to show you that the flux in basic electrodes does not absorb/adsorb (call it however you like) hydrogen but moisture?
Reply:Originally Posted by InsanerideI thought LIBERTY ships were made from concrete due to shortage of steel during the war.Since were on the topic of 7018 and cement; can someone explain the process cement goes thru?  I know you start with lime and some times calcium sulfate (similar to flux?) and sand for cracking but water is a main ingredient. Ive noticed an exothemic or heats of formation from fresh cement and told it takes 200 years to fully cure.  The reason I ask is; it seems to me that 7018 adsorbs hydrogen in the presence of moisture and I think the flux uses lime or calcium sulfate.
Reply:All though built in the same time frame and with the same methods the Schenectady was technically a T-2 class tanker and not what I generally think of as being a "Liberty Ship".   They actually fixed the Schenectady and got quite a few years of service out of it.All though "welding" (and the way it was being done at the time) was originally thought to be the cause of these failure problems with the Liberty Ships and T-2 Tankers later investigations actually showed it to be much more about the low grade of steel that was being used and some design issues.Originally Posted by MinnesotaDaveAre you starting this again?  7018 does not adsorb hydrogen - it chemically bonds with the moisture in the air, then in the energy of the arc the moisture dissociates into hydrogen and oxygen.The moisture is chemically bonded to the 7018 flux, this is why it takes so many degrees to re-bake the electrodes - it take energy to break the bonds.I believe it may come down to the difference between Chemisorption and Physisorption - but I do not have the right technical background to be sure.From the AWS Welding Journal:[snip]During welding, the moisture dissociates into hydrogen and oxygen. The oxygen may form oxides within the weld, or recombine and evaporate. Hydrogen becomes trapped as the weld metal cools and, if sufficient hydrogen is present, cracking can occur.[snip][snip]In this instance the failure mechanism results from the breakdown of moisture, where hydrogen is absorbed by the weld pool from the arc atmosphere.[snip][snip]Hydrogen.The source of hydrogen is the moisture retained within the electrode coating. Baking of electrodes to ensure the moisture is removed prior to welding is essential. Other potential sources of hydrogen involve paint and grease and failure to remove moisture from the weld area prior to welding[snip]
Reply:Hydrogen Embrittlement (or if you prefer Hydrogen Induced Cracking) is a delayed failure mechanism that takes time to occur.   I've worked on some things where the inspection (X-ray) was purposely delayed for 72 hours after completion of welding so that if any hydrogen induced cracking was going to occur it had time to do so and could be detected.
Reply:This gives a good general idea of the different things used in the composition of fluxes for various stick welding rods.http://www.nbent.com/table.htm
Reply:Originally Posted by HT2-4956This gives a good general idea of the different things used in the composition of fluxes for various stick welding rods.http://www.nbent.com/table.htm
Reply:Originally Posted by MinnesotaDaveThat's a pretty nice table, I had not seen them listed together that way
Reply:Originally Posted by HT2-4956One interesting tid bit I got from that chart was how they substitute in Potassium Titanate and Potassium Silicate in place of slag formers like Titanium Dioxide and Sodium Silicate to act as arc stabilizers so that 6011 and 6013 run better with AC current.   It's to bad the chart didn't show what it is they use for making the specialized 7018 that's designed for use with AC.
Reply:Originally Posted by MinnesotaDaveIt could be the increased Titanium Dioxide?In the 7018AC version it's up about 15%, but the regular version is only 0%-5%
Reply:Originally Posted by HT2-4956Now I'm wondering if the AC version of 7018 can achieve some of the lower diffusible hydrogen ratings like some of DCEP 7018's are rated for.   While AC might be fine for running 7018 on for stuff around the farm or the garage hobby welder I just don't know of any critical applications where they run 7018 on anything but DCEP.
Reply:Originally Posted by InsanerideI thought LIBERTY ships were made from concrete due to shortage of steel during the war.Since were on the topic of 7018 and cement; can someone explain the process cement goes thru?  I know you start with lime and some times calcium sulfate (similar to flux?) and sand for cracking but water is a main ingredient. Ive noticed an exothemic or heats of formation from fresh cement and told it takes 200 years to fully cure.  The reason I ask is; it seems to me that 7018 adsorbs hydrogen in the presence of moisture and I think the flux uses lime or calcium sulfate.
Reply:Originally Posted by In UtopiaConcrete ships have been around for a while, just never made the grade.http://www.crystalbeach.com/selma.htm
Reply:Most of the things mentioned in your post are plain wrong.
Reply:Originally Posted by InsanerideUtopia, thanks for understanding and reading my question.HT2-, the H2 you mention is called deuterium. The two H form an ionic bond to match that of He.H2O forms an ionic bond to match Ne. WillieMac first mentioned H2 but was to outlandish for Insaneride.HT2-, your posts and knowledge are genuine and you dont have to gooogle your responses like the phonies.Minnesotadave, my question was about Liberty ships and cement.
Reply:Originally Posted by InsanerideUtopia, thanks for understanding and reading my question.HT2-, the H2 you mention is called deuterium. The two H form an ionic bond to match that of He.H2O forms an ionic bond to match Ne. WillieMac first mentioned H2 but was to outlandish for Insaneride.HT2-, your posts and knowledge are genuine and you dont have to gooogle your responses like the phonies.Minnesotadave, my question was about Liberty ships and cement.
Reply:So now research is bad?An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.
Reply:Originally Posted by Willie BSo now research is bad?
Reply:Originally Posted by MinnesotaDaveI'll admit to being one of your "phonies" - I look up information quite often to support what I think I already know.The reason is the quote in my sig line.I also do it to learn new things and explore ideas - make fun of it if you wish.
Reply:Deuterium (δευτέριο) meaning is closer to second than to double.HT2 is right, deuterium is an isotope.
Reply:Rahtreelims, I didnt mean to pollute your thread. I thought I had a valid, useful interesting question. I thought calcium sulfate was used in the flux but HT2-'s table shows it to be calcium carbonate. Gypsum used to be calcium sulfate but has switched to calcium carbonate. My question still applies to CaCO3 or CaSO4 but now I dont care.  As far as 7018 goes, I like it.
Reply:Originally Posted by InsanerideWhoa,  I was asking about cement.  Good thing I didnt ask about hydrolic cement.HT2-  Im not sure what your saying. Sounds like you re gurgetated what I said.FYI deu or deuce in deuterium is Greek for two as in two hydrogen.Maybe the Greek guy can confirm it if he knows any Greek.MDave, I thought the quote in your sig line was to make fun of me. Research is good I just dont like plagerism. Peace MDave.
Reply:Originally Posted by taz00Deuterium (δευτέριο) meaning is closer to second than to double.HT2 is right, deuterium is an isotope.
Reply:That old saying about how some people continue to live because killing them involves to much paper work might just apply here.
Reply:Originally Posted by InsanerideSecond and double both mean deuce or 2 you phony Greek.  Yes deuterium is an isotope and I know what that means. Do you or do you have to google it first?
Reply:Originally Posted by taz00Dude, you seriously gotta lay off the bottle ...
Reply:Originally Posted by HT2-4956That old saying about how some people continue to live because killing them involves to much paper work might just apply here.
Reply:The series Northern Exposure involved 2 old guys in incredible shape, 1 captive transplant New Yorker and a hundred Alaskan redneck intellectuals. Somehow I'm caught in the middle of an episode. Where's the fire escape?Instead of debating the translation of Greek language, explain how we preserve the ability of 7018 to keep diatomic hydrogen out of our steel crystalline structure. I'm always concerned when I buy 7018 in a plastic container with rough texture "sealed" with a single wrap of scotch tape. Shouldn't this be hermetically sealed? or is Airgas expecting me to have a rod oven? How about cellulosic flux?An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.