thePetroStreet

Can any one let me know the difference b/w E-7010 & E-7018. Which one is used where? What are the advantages & disadvantages of both?

E-7010 is used where deep penetration is required. You get an excellent root pass with E-7010. It's a fast freeze type electrode but has a disadvantage of hydrogen content. When welding you would be requiring high pre-heat so that you can avoid any hydrogen induced cracks - cold cracks. Whereas E-7018 is a low hydrogen electrode which saves you from any cold cracks as induced hydrogen is too low.

> E-7010 is a non-backing electrode whereas E-7018 must require backing before welding.
> There is less chances of weld porosity with E-7010 as compared to E-7018.

Thanx for sharing knowledge.
What shall be the minimum pre-heat temperature in case of E-7010.
One of our contractor has suggested to use E-7010 for filling capping on cross country gas pipe line construction. For root welding E-6010 would be used. Shall we go with E-7010? Any suggestions/precautions for its use?

Also is there any method to check induced hydrogen in the weld joint while using E-7010? Where i can find reference of this electrode in code?

In my opinion, if you are using E6010 for root pass then filling capping must be done with E7018 instead of E7010.
E7018 is just matchless for carbon steel piping filling pass welding. But if you have a valid PQR for E7010, you can go ahead.

In this case do we require pre-heating while using E-7010?

Nabeel Ahmed Qureshi wrote:Thanx for sharing knowledge.
What shall be the minimum pre-heat temperature in case of E-7010.
One of our contractor has suggested to use E-7010 for filling capping on cross country gas pipe line construction. For root welding E-6010 would be used. Shall we go with E-7010? Any suggestions/precautions for its use?

It is common practice to weld cross country pipelines using E7018 HYP electrodes for downhill root, hot pass, fill & cap under API 1104 code.

QCRobert

Dear Robert,
Yes this is known that 7018 can be used but what about with 7010 A1 for filling & capping?

•AWS Class E7010-A1 DCEP (Electrode Positive) Electrode Imprint Marking: 7010-A1 Code and Specification Data: AWS A5.5, ASME SFA 5.5 Group F-3 Military - MIL-E-22200/7, MIL-7010-A1
As long as your contract specs allow it, yes you may use E7010 A1 for filling & cap but may I ask why you wish to use the A1 category? That is usually used on carbon-moly piping or casting applications where high tensile strength and creep resistance at high temperatures and high pressure are desired. In adddition, some common applications have included shaft build-up and repair, gear teeth, boilers, oil well casting, forging dies, and alloy chain links.

Preheat would be minimal, 50 degrees F unless thickness values approach 3/4" +.

Are you in the process of developing a WPS? What matl & thk is the pipe and what fluid are you transferring? What code are you welding to?

Robert