SRI,

What type of machine are you referring to? Most machines for SMAW, GTAW, GMAW, FCAW can not be "calibrated". You can check the output with a calibrated ammeter or voltmeter, but disagreement between the actual output and the machine settings is normal. The difference is due to variations in arc length, cable size, cable length, and other factors. When amperage and voltage are critical factors, such as when a maximum heat input is specified on the weld procedure or when welding thin materials, a portable hand-held ammeter/voltmer that is calibrated is a better method than using gages that come with the welding machine. For automated welding, periodic checks of the welding machine output vs. settings on the machine are a good idea and may be considered "calibration" depending on how it is treated in your QA program.

I know of no codes or standards that require "calibration" of welding equipment, except in the case of fully automatic welding processes. Some codes have statements that require the Inspector to check to that welding machines are working properly, but that doesn't mean they have to be calibrated nor does calibrating gages on a welding machine mean the welding machine is working properly.

Hope this helps,
Marty

I don't know if this will help but the AWS D1.5 Bridge Welding Code says:

"4.26.1 Equipment used to measure variables shall be accurately calibrated. The contactor shall verify, at least every 3 months, the accuracy of meters adn other devices used to record or display welding variables. The equipment used for verifying meters and other devices shall be certified annually.

4.26.2 Correction charts or similar methods may be used to compensate for meter error when approved by the Engineer."

I am not positive but I think the D1.1 Structural Welding Code does not address calibration intervals. Maybe others can verify that or correct me if need be.

I don't know offhand what other codes require. Recently, we had a job where the Project Specifications required weekly accuracy verification checks of all welding equipment used. So it is possible the codes can be superceded in that manner.

Hope this helps,
CHGuilford