Unlike the plumbing or electrical crafts, welding certification is not a "license". There is not a single welding certification test that will certify you to weld everything. In order to become a certified welder, you need to take a welding test to a specific code. This test is a practical exam that explores your ability to make sound welds. There is no written test for any commonly used code.*
In the US, most organizations accept and operate under the codes written by AWS (the American Welding Society). The first step is to identify which welding code to be certified to, as welders are only certified to weld within the code parameters of the test they have taken. For more information on how to select a welding code to test to, please visit our other blog article, What Welding Certification Do I Need?
AWS has accredited test facilities (commonly known as ATFs) throughout the US, where a welder certification test can be taken. For more information on the ATF program, as well as where to find one in your area, please visit AWS's website-AWS ATF Program. Earlbeck Gases & Technologies operates Maryland's only ATF center.
A certification test can also be administered at a test center that is not accredited by AWS, however, they do not have the ability to issue AWS certified welder ID cards and your certifications will not be listed under the national AWS certified welder registry. These certifications done by non-ATF facilities are still valid under audit, however they are not portable between employers.
Once you have selected your testing center, call to set up an appointment. When you arrive, they will give you instructions on the fit-up required for your test. Once the piece is in position and welding begins, it must remain in that position until completed. This includes grinding. Though none of the Codes impose a time limit on the welding of a test piece, most qualification tests can be completed by a skilled welder in less than 4 hours. When completed, the weld will be visually inspected as well as bend tested. If the test passes, you will receive your certification for that code.
* No AWS or ASME code requires a written exam for welder certification. The only commonly used code that does is the Department of Denfense's military publication NAVSEA S9074-AQ-QIB-010/248 which is typically used for welding machinery on military shops.