16 mo3 alloy plate welding process

[nithi]

dear all please give me a solution of my problem.......16mo3 to 16mo3 plate welding u.t test failed so wat is the problem in process give me a any procedure or standard arc welding electrorod is aws e 7018 a1

[BornToSin]

change the welder lol
the electrode is E7018-A1H4R

[suhairi]

What type of defect..most probably is due to welder competency..

[nithi]

thanks mr.moderator ...........i found in u.t side wall lack of fusion ........i need preheet and interpass temperature.............

[inconel]

nithi,

preheat and interpass temperature have nothing to do with lack of fusion ! Your welder is not capable (may be two times...next time he might be capable after adequate training)to melt and merge the parent metal sidewall with the corresponding electrode(filler metal)...

[nithi]

ok sir ...i have on dought is there problem with our electroad we are using AWS A 5.5 E 7018 A1 ? AND pls define what is different between AWS A 5.5 E 7018 A1 and E7018-A1H4R pls help me very urgent .........

[inconel]

ok sir ...i have on dought is there problem with our electroad we are using AWS A 5.5 E 7018 A1 ? AND pls define what is different between AWS A 5.5 E 7018 A1 and E7018-A1H4R pls help me very urgent .........

Nithi,

Chemical composition of both electrodes(7018-A1 and 7018-A1H4R) are same.The difference is the diffusible hydrogen content(mL/100g) in both electrodes.When strict quality control required situations,fabricators prefer to hit with H4R designation as it contains less diffusible hydrogen content compared to normal grade and H4R electrodes are designed to maintain that state up to a certain period of time as well...ie The electrode can maintain it's diffusible hydrogen level as per the designation up to 4-8 hours once it taken out from it's vaccum packed container...This time may vary according to manufacturer and you have to verify by reviewing the consumable MTC or check the Vacpac cover of electrode to trace it....For better understanding,please review ASME SEC II Part C, SFA 5.5 Annex A2.3 which is equivalent to AWS A5.5...I have attached the excerpt from that standard below for your instant reference...

PS:Usage of electrode with H4R designation is a precautionary measure to reduce the chances of hydrogen induced -----ing as much as possible during critical component fabrication.

"A2.3 Optional supplemental designators are also used
in this specification in order to identify electrode classifications
that have met certain supplemental requirements
as agreed to between the supplier and the purchaser.
The optional supplemental designators are not part of the
classification nor of its designation.
An optional supplemental designator “HZ” following
the classification designation, which consists of four or
five digits plus “M,” or a composition suffix such as
“-A1,” “-B2,” or “-C2L,” indicates an average diffusible
hydrogen content of not more than “Z” mL/100g of
deposited metal when tested in the “as-received” or conditioned
state in accordance with ANSI/AWS A4.3. See
Section 16 and Table 12. Electrodes that are designated
as meeting the lower, or lowest hydrogen limits, as specified
in Table 12, also are understood to be able to meet
any higher hydrogen limits. Therefore, as an example,
an electrode designated as “H4” also meets “H8” and
“H16” requirements without being designated as such.
The letter “R” is an example of a supplemental designator
used with certain low-hydrogen electrode classifications.
It identifies classifications that have been exposed to a
humid environment for a given length of time and tested
for low moisture absorption in addition to the standard
moisture test required for classification of low-hydrogen
electrodes."



Hope this helps.

[BornToSin]

ok sir ...i have on dought is there problem with our electroad we are using AWS A 5.5 E 7018 A1 ? AND pls define what is different between AWS A 5.5 E 7018 A1 and E7018-A1H4R pls help me very urgent .........

again, it's not problem in electrode. it's not problem in preheating too, cause acc. to EN's 16Mo3 requires preheating only if thickness is over 30mm, and -----ings occures because of not preheating, not lack of fusion...but I don't think that your plate is that dimensions...
after porosity, lack of fusion is most common welding imperfection and the problem is most likely in welder. incorrect parameters (too fast or too slow welding), too much electrode weaving etc. it could be also if your plate's surface has oxidizes, so you can do some blue vitriol checking just to be sure, but probably it don't have sense cause again, it's human factor - welder

[nithi]

thanks very much my dear senier members and mr. moderator.........i have to change the welder...........