Storing and Re-drying Electrodes

Shielded Metal Arc Welding (SMAW) electrodes must be properly stored in order to deposit
quality welds. When electrodes become absorb moisture from the atmosphere, they
must be dried in order to restore the ability to deposit quality welds. Electrodes
with too much moisture may lead to cracking or porosity. Operational characteristics
may be affected as well. If you’ve experienced unexplained weld cracking
problems, or if the electrode arc performance may have deteriorated, it may be
due to your storage methods or redrying procedures.

All electrodes must be dried to the right level to perform properly. Even a small
amount of moisture in low hydrogen electrodes can lead to major weld problems
such as internal porosity, weld cracking or poor operating characteristics. We
will look at three different types of electrodes:

1.
Low Hydrogen Electrodes

Storing
and exposure limits

SMAW electrodes with low hydrogen coatings, such as E7018 and E8018-C3, must be
kept very dry since hydrogen induced cracking can easily occur, especially in
steels that are 80,000 psi and higher yield strengths. To keep these electrodes
dry during storage and to prevent welding defects,
here are some suggestions:

• Purchase
  these electrodes in hermetically sealed containers, which provide excellent protection
  against moisture pickup.
• Do
  not open the hermetically sealed containers until the electrode is needed for
  use.
• When
  the cans are opened, electrodes that will not be immediately used should be placed
  in a cabinet at 250 degrees to 300 degrees (120 – 150 degrees C).
• Electrodes
  should be supplied to welders in quantities that can be consumed within time limits
  that are dependent on the electrode type and strength level. For example, standard
  E7018 electrodes can be safely be exposed to the atmosphere for 4 hours whereas
  standard E11018 electrodes are restricted to only ½ hour.

Re-drying

When
the hermetic seal is broken, (either deliberately such as when a can is opened,
or accidentally as when a can is punctured) a can of low hydrogen SMAW electrodes
must be redried. When the electrodes have been exposed to the atmosphere for period
of a few days, the electrode can be re-dried. The following re-drying procedures
should be used:

• To
  re-dry, electrodes should be removed from the can, and placed in suitable oven.
  The electrodes should be spread out in the oven so that all electrodes will reach
  the drying temperature. The can of electrodes should not be put in the oven; the
  cardboard liners can char, and the temperature of the electrodes will not be uniform.
• When
  the electrodes are initially placed in the oven, the temperature should not be
  greater than half the re-drying temperature. The electrodes should be held at
  that temperature for ½ hour before heating the electrode to the final temperature.
• For
  mild steel low hydrogen electrodes governed by AWS A5.1 (such as E7018), the final
  re-drying temperature is typically 500-800 degrees F. For low alloy electrodes
  governed by AWS A5.5, the final re-drying temperature should be 700-800 degrees
  F. The manufacturer’s recommendations should be followed.
• One
  hour at the listed final temperature is satisfactory. Do not dry electrodes at
  higher temperatures. Also, several hours at a lower temperature is not equivalent
  to using the specified requirements. Moisture becomes chemically bonded (absorbed)
  to the electrode coating and those chemical bonds must be broken at the proper
  temperature for the proper length of time or the electrode can be damaged.
• Any
  electrode should be discarded if excessive re-drying causes the coating to become
  fragile and flake or break off while welding. Or, dispose of the electrode if
  there is a noticeable difference in handling or arc characteristics, such as insufficient
  arc force.

2.
Austenitic Stainless Steel Electrodes

Storing
and exposure limits

Austenitic
Stainless Steel for SMAW must be kept dry. Typically, the first problem that will
be noticed with welding with such electrodes that have been contaminated with
moisture will be weld porosity. Other operational characteristics may also be
affected. To keep these electrodes dry during storage, here are some suggestions:

• Store
  these non low hydrogen electrodes from the freshly opened containers in heated
  cabinets at 100 degrees – 120 degrees F (40 – 50 degrees C).
• Do
  not use higher temperatures, particularly for electrodes from the “Fast Freeze”
  group, which includes Lincoln Shield-Arc® and certain types of Fleetweld®
  electrodes.

Re-drying

Follow
these simple storage, exposure and re-drying techniques to ensure the highest
quality welds, as well as the best operational characteristics from your SMAW
electrodes.

Reprinted
from Lincolnelectric.com