Oven backing on E7018R

[Srinivas Engr]

Dear All, May I know oven backing is need for E7018R(Moisture
resistant electrode)????, I am well with 7018 Backing, But whats with
E7018R????

[Gary_K...@lincolnelectric.com.sg]

The R is an optional designator in the AWS filler metal specification that allows for longer exposure times before rebaking. I believe it is 9 hours of exposure before having to return for a complete re-baking cycle.

The packaging will determine whether you can immediately use the electrode. If it is a hermetically sealed (also called vacuum sealed), you can use straight from the packaging. If it is a non-sealed package than you must bake the electrode the same as a non-R designated electrode.

The Lincoln Electric Company (Asia Pacific) Pte. Ltd.

M +65 9641-2821

Sent from my BlackBerry wireless device

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[Yadav Shiva]

Dear Srinivas,

                       R -- Designates that a covered electrode is moisture resistant and has been tested in a humid environment of 80°F (26.7°C) and 80% R.H. for nine hours and still showed covering moisture less than 0.4% by weight. Example: E7018R, E8018-B2R, E7018-1R and E8018-W1R

 

The R designated low-hydrogen classification gives the user reasonable assurance that the electrode can be exposed for up to nine hours to 80^oF/80% R.H. without exceeding 0.4% moisture in the covering. This enabled ANSI/AWS D1.1, Structural Welding Code -- Steel, to permit electrodes designated as E7018R or E7018HZR to be used even if they are exposed to ambient conditions for up to nine hours. For high strength, low-alloy electrodes, the actual hours of exposure under atmospheric conditions may have to be limited to less than nine hours to control moisture to lower levels than the 0.4% threshold used to differentiate moisture-resistant covered electrodes from standard covered electrodes in the standard nine hour moisture exposure test

Moisture E7018R E7018-1R E7018H4R E7018-1H4R

 

Regards,

Yadav Shiva Chelliya,
Inspection Engineer,
Doha Qatar,
+974-6166465

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