Storage of Welding Rods and Electrodes

1. SCOPE
2. GENERAL
3. STORAGE

3.1   Storage of Unopened Containers

3.2   Storage of Bare Rod and wire

3.3   Storage of Covered Electrodes

4. USAGE
5. RETURN TO STOCK
6. ELECTRODE RECONDITIONING

TABLE I – Rebake Temperatures

Storage of Welding Rods and Electrodes

1. Scope

This article provides information for maintenance and construction personnel when storing and using both bare and covered welding filler metal rods and wire.

2. General

2.1  Filler metal is categorized as bare, low hydrogen covered, or conventionally covered. The mineral base coating used on low hydrogen steel electrodes is also applied to austenitic stainless steel and nickel alloy electrodes. Each type requires individual care in storage. Filler metals are classified in accordance with AWS classification system.

E   =    Arc Welding covered electrodes for Carbon steel, low alloy steel, stainless steels and Nickel alloys

R   =    Welding rod which is heated by metals other than carrying current

ER =    Indicates a filler metal which may be used as an arc welding electrode or as a welding rod

Electrodes are further categorized for tensile strength, type of covering, type of current, welding position, and alloy in weld deposit.

2.1.1  Bare rod and coiled or spooled wire can corrode or pick up dirt, grease, moisture, and other foreign material on their surfaces during storage and use. This accumulation may cause porous and defective welds. Nickel and

high-nickel alloys are especially prone to cracking during welding when even small amounts of oil or grease are present. Carbon steels and aluminum alloys readily oxidize from any moisture condensate and this oxide causes weld porosity.

2.1.2  Electrodes with low hydrogen, iron powder low hydrogen, lime and titania-type coverings may produce porosity and cracking in steel weld metal and base metal if used when the coverings are damp or wet. This hydrogen embrittlement problem is aggravated as the thickness and strength of the materials increase. Similarly, lime and titania mineral coatings on stainless steel and nickel alloy rods produce porosity in the deposit if the coatings are damp. It is known, however, that the rate of moisture absorption varies between electrodes of different vendors. Therefore, the recommendations  contained in this standard are conservative and provide remedies for the worst cases. These electrodes are classified by AWS-ASME with numbers ending in 15, 16, 18, or 28.

2.1.3  Steel electrodes with conventional type coverings normally do not require any special dry type storage. They are not affected adversely by normal humidity conditions. They may, however, cause erratic arcing and porosity or cracking in the weld deposit if used after prolonged exposure to high humidity. These electrodes have classification numbers which end in 10, 11, 12, 13, 20, 24, 27, or 30.

3. Storage

3.1 Storage of Unopened Containers

Unopened and undamaged containers made of sealed metal, or other moistureproof material, shall be stored in a clean, dry area. A compartmented  rack or cabinet is recommended for ease of identification.

3.2 Storage of Bare Rod and Wire

3.2.1  Proper storage of welding rods and wire is essential to avoid contamination. All bare rod and coiled and spooled wire shall be stored in the original undamaged containers wherever possible, except for small quantities issued for use. Keep containers tightly closed except when removing or replacing rods or wire. Keep containers in a clean, dry area. Do not leave packages of filler metal outdoors or in unairconditioned  buildings because the greater variation of temperature and humidity increases the possibility of condensation. Experience has demonstrated that these undesirable storage conditions may adversely affect electrode performance. Shelf life is indefinite if stored properly.

3.2.2  Bare rods from opened containers shall not be left scattered about to become soiled.

3.3 Storage of Covered Electrodes

3.3.1  Storage of Low Hydrogen (Mineral) Type Covered Electrodes (2.1). Open original containers only as needed. Store electrodes removed from containers, in thermostatically  controlled ovens at 107  C to 149 C (225 F to 300 F). Ovens of this type can be purchased. Use this type of electrode directly from the container and within four hours of removal.

3.3.1.1  Where E-7018 electrodes are used on structural type mild steel, and minor porosity can be tolerated, the storage shall be in accordance with 3.3.1.

3.3.2  Storage of Conventionally  Covered Electrodes (Types EXX 10, EXX 11). These types of electrodes shall have off-the-floor storage in a dry area. Do not place them in heated storage (ovens) because of the adverse effect on electrode operating characteristics.  If these types of electrodes are to be exposed to unusually high humidity or wet conditions, they may be stored in heated cabinets at 38 C to 52 C (100 F to 125 F). Electrode ovens are available in the market.

4. Usage

Never remove more than eight hours supply of electrodes from holding/keeping/warming or drying oven unless a portable electrode heater is provided for keeping the electrodes at 107 C to 149 C (225 F to 300 F) at the location of usage.

5. Return to Stock

5.1  At the completion of a job or shift, return all of the above referenced electrodes to the appropriate storage oven or cabinet. See section 6, for low-hydrogen electrodes.

5.2  Each site shall formulate a plan for ensuring that covered electrodes are returned to stock in good shape.

5.3  Electrodes previously exposed to water. Physically scrap them.

6. Electrode Reconditioning

6.1  Low hydrogen (mineral) covered electrodes previously exposed to humid conditions shall be reconditioned before use.

6.1.1  Electrode coverings shall not be exposed to the rebaking temperature (Step No. 2) without first reconditioning them at a lower temperature (Step No. 1). Failure to observe this precaution may result in breakdown of electrode coverings. Recommendations for rebaking vary from manufacturer to manufacturer. In the absence of specific rebaking information use the typical rebaking conditions given in Table I.

Table I – Rebake Temperatures

6.1.2  Iron powder low hydrogen electrode listed in Table I shall be charged into the oven whose temperature is not greater than 149 C    10 C (300 F ± 50 F) and shall have the temperature raised not more than 149 C (300 F), per hour from 260 °C (500 °F) up. The total time above 260 °C (500 °F), and holding time shall not exceed five (5) hours. Minus temperature may be reduced to -50 °C but baking time will have to be increased.

6.1.3  After rebake immediately move electrodes to the electrode holding oven, without letting them cool below the holding oven temperature.

6.1.4  Iron powder low hydrogen electrodes shall not be rebaked more than once, to ensure consistent covering quality. Baking at excessively high temperatures may make the coating more friable.