Is it necessary to calibrate and certify the portable electrode quivers, rated for 250W @ 48 - 75VDC and fed from the welding power, used for the SMAW applications, as one of our clients is insisting for it?
We have about 1,500 quivers and being used for the last 25 years without any such calibration/ certification, considering that it is a tool for the welders to keep the processed/ hot electrodes transferred from the nearby holding ovens and to retain its temperature by adding certain heat input. The double wall type quiver has no thermal insulation, the heating element is attached into the bottom plate with a heat sink, the thermostat rated for 30 - 120 Deg.C is controlling the heat sink temperature and the heat is transferring by conduction. It cannot provide a stable temperature, as a result of ambient variation, voltage variation (ARC voltage and OCV) and quantity & temperature of the electrode being stored.
Considering their design, application and our experience, we think, there is no meaning in spending extra efforts for calibration/ certification activities other than inspection/ maintenance for ensuring the physical integrity and functionality.
Please review the above and comment. If calibration is required, what will be the acceptance criteria for the subject quivers used to handle the carbon steel low hydrogen electrodes (E 7018-1, E7018, E7018-1, E7028 etc.), transferring from the nearby holding ovens at 120 - 150 Deg.C?
Regards
You did not mention code you are using. My response is based upon D1.1-2002, 5.3.2.2. It references you to Table 5.1 for exposure time limits. The 3rd bullet says electrodes are to be held in quivers but you do not need heated quivers. Based upon that fact, I do no see a need to have a calibrated/certified quiver.
To help smooth over your disagreement with your client, you could contact the manufacturer to see what their maintainence check of a heated quiver covers. With a decade of experience running a calibration company, I would say there are a multitude of items that can not be calibrated, or at least the range of operation is so large as to be difficult to quantify and document accurate results. A simple operational verification to say the quiver in question is heating and sealing adequately should satisfy your client.
Thanks for the response.
The primary code that we used is AWS D1.1. The table 5.1 gives the exposure limits, however, it does not says anything about the temperature span.
You can make this a moot point by simply returning the electrodes to the oven before their exposure limit is reached.
Mike Sherman
Unless your clients contract or specifications state otherwise, the permissible atmospheric exposure of low hydrogen electrodes is 4 hours. However, this 4 hour limit can be increased to up to 10 hours if extensive test are done and the moisture cotent values of A5.5 are not exceeded etc....AWS D1.1 also states Electrodes shall be issued and held in quivers, or other small open containers. Heated containers are not mandatory...... In other words the old leather rod pouch is sufficient. I would suggest showing the client what AWS Codes and specifications are for welding rod storage and use, in black and white from the book ,and any expence for calibration of quivers should not be your responcibility because it is not mandatory. It kind of sound like there being picky or maybe they don`t know what there talking about..... Have a good one!
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