7018 trouble shooting

By ShowDownZero Date 10-21-2010 02:08

Hello everyone.
I am doing a job right now and I am encountering a few problems getting the 7018 rods to run correctly.
I will explain a bit about whats going on here as best I can for now.
The companys 7018 rods that I am being given are running like total crap in all positions 3G and 3F and 4G is near impossible. They run smoothly for just a bit then start to spatter and sputter all over the place and destroying my puddle I cant tell what the hell I am doing because of that.
they are leaving a brownish white thin slag that is hard to remove I am used to seeing 7018s making a black slag that peals its self or chips off easy then again in the past I have run almost exclusively 7018 Excalibur.
The rods this company has are 7018 T1 not sure what the T1 means I have never seen it before.
I have tried everything I know to getting it to work right I experimented with arc lengths, amperage settings, changing techniques, cleaning the metal, moving the ground, and still nothing.
The Machine I am using is a some what old Hobart engine driven welder that looks like it has not been taken care of.
The engine driven welders are something else I have never used before, I know their CC so they are a little bit different than the electric machines.
It can however run 6010s and 7024 good tho not perfect.
I should also note theses rods are not being stored correctly so the moisture content is through the roof.
I have never seen what happens when 7018s are not being stored correctly either so that could possibly be the problem.

By aevald

Date 10-21-2010 05:23

Hello ShowDownZero, you have a lot of possible variables that could be influencing the way that those rods will run or are running. Is there any possibility that you have misread the designator after the E7018 number? There are designators such as: -1, this is associated with an E7018 electrode that has met -40 charpy impact values, I believe(might be off a bit on that one), this should not be a factor for how you are describing the way that these rods run.
One possibility for a part of the spitting and sputtering could be from the excessive moisture that you say could have been picked up by the poor storage regimen, this could be compounded by possible electrical or thermal arc blow issues. A careful check of all electrical connections for best continuity might help to rule out that portion of a possible problem. Another factor could certainly be the condition of the generator portion of the machine itself, if it has a lot of corrosion and muck between the brushes and armature this could affect arc stability and smoothness. A check of the brush holders to ensure a good contact and correct pressure against the armature will additionally help to rule out possible issues, an additional check of the armature contact points for proper cleanliness will insure good continuity and machine performance. If the machine has a range selector or polarity selector there are additional points that should be inspected for continuity/corrosion issues. Amperage adjustment rheostats are yet another possible contributor. I think you get the idea here. A quick way to possibly determine if this is truly a machine issue as opposed to one with the electrodes is to take some of the rods and run them on another welder that you are confident in welding with, if the same results are exhibited I would look to the electrodes. As to your concerns with differences between the CC output of the engine driven welder being different from electrically powered shop sources, they all utilize CC current, the waveforms might be slightly different based on what type of system is producing the CC but it is CC all the same. You've got motor/generators(these can be driven with electric motors or combustion engines), transformer/rectifiers, inverters, and possibly others that I don't know of or remember that will produce the CC used for SMAW(stick) welding. You could run stick with CV as well, but it's not very commonplace. If you can try to include the exact brand of rod, also carefully check to see that your polarity is correct, I mention this because even though the machine might have the "correct" badging showing the correct polarity there are other reasons why this might be reversed. A volt meter set to DC current and attached in correct phase to the output studs will yield a voltage reading only, if the polarity is incorrect there might be a (-) sign in front of the numerical voltage reading indicating that the current is reversed. Hope this might help a bit. Good luck and best regards, Allan

By Joseph P. Kane (****)

Date 10-21-2010 11:31

Show Down Zero

Here is what happens when E-7018 is not stored properly.

Courtesy of Al Moore.

Attachment: 2010-10-14Hydrogenevulsionphoto.pdf (109k)

Attachment: 2010-10-14Hydrogenevulsionphoto-1.pdf (109k)

By ShowDownZero Date 10-22-2010 01:26

Joseph P. Kane

Can you tell me what are some of the long term and short term problems associated with welds done with improperly stored low hydrogen electrodes aside form hydrogen cracking.

By Joseph P. Kane (****)

Date 10-22-2010 13:01

I cannot answer that question definitively. Theoretically, Hydrogen caused micro-voids can coalesce and cause cracking Later on. There are some different theories about chemical reactions at elevated temperatures. The most immediate thing I noticed was porosity, but I cannot say that the bubbles weren't caused by Nitrogen or hydro carbons or by Oxygen. There are other members of this forum with real experience and experimental experience in failure analysis who could chime in here, and add more to this topic

By welderbrent (*****)

Date 10-23-2010 16:19

ShowDown,

Welcome to the AWS Welding Forum.

The first thing that comes to my mind with your question of long and short term problems associated with these welds is: collapsing buildings, machinery breakdowns, and other such complications from improper welds.

What else would one expect from welds that are not as sound as they were intended to be? If it is very obvious and provable that there are higher instances of hydrogen cracking, porosity, reduced tensile and yield strength, etc, then the end result, ie long and short term problems, would be catastrophe in one form or another.

The extreme ultimate end being the possibility of the loss of life.

Have a Great Day, Brent

By ShowDownZero Date 10-22-2010 01:17 Edited 10-22-2010 01:30

Thank you Aevlad. I shall go in to work tomorrow armed with that knowledge hopefully I can fix the problem.

About the polarity issue that you mentioned That was a problem I have already fixed on two of the machines along with air filters and leads.
This company I am doing some work for is a metal ore processing plant and is a welders nightmare believe me when I say the amount of problems they have with all of their equipment is mind numbing. I spend most of my time with them going around and fixing crap and pointing out issues that I should not have to.
My next problem will be to give them enough information for them to believe me when I tell them how something should be done so far they seem to think I complain to much and take to long In reality I think I am the only real welder this place has ever seen.
It sucks when your given so many problems that its just overwhelming but It pays till I can get back to doing some serious work where the people I am with actually care about what their doing.