Asme B31.1 2018 [inspection-academy] jq37

Welder Certification

This presentation was developed by the Collaboration for Nondestructive Testing Education to address one of the most misunderstood subjects in the field of welding:

Welder Certification

The following questions and others will be addressed in this presentation. • • • • • • •

What is certification? Why is certification important? How does a welder get certified? How do codes relate to certification? When and where can a person get certified? When is recertification required? What can be welded after certification?

What is Certification? • Certification is a process of providing written testimony that an individual is qualified to do certain work. In other words, “Certification” is the actual paperwork stating the details of the qualification. • The qualifications of an individual are based on education, level of training, work experience and a demonstration of welding skills.

Why Is Certification Needed? • Welder certification is important because welding personnel and their employers must have a great deal of confidence in the results of their work since it often has safety and/or significant financial consequences.

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The performance of bridges, buildings, pressure vessels, aerospace components, etc. relying on sound weld metal being deposited.

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Using certified welders should produce more consistent quality welds. This along with nondestructive testing and destructive testing help assure engineers that the weld will perform as designed.

Who Determines Whether Certification is Required? • A welding job must usually be performed in accordance with a welding specification, code or procedure. These documents specify what certification is required. • The employer is responsible for having welders with the proper certification perform the work.

Welding Specifications, Codes and Procedures • Weld specifications, codes, and procedures are documents that give the parameters for a welding job.

• They address topics such as base material, filler material, preheat, post heat, inter temperature, welding process, position, t detail, and post weld heat treat. • Certification testing is performed in accordance with a welding procedure so that there are guidelines to follow.

What Are Some Common Welding Codes? Some common welding codes that welders can be certified to are: – American Welding Society (AWS) used for bridges and buildings. – American Society of Mechanical Engineers (ASME) used for high pressure piping. – American Petroleum Institute (API) piping used for petroleum transmission lines. – Military Standards (Mil Std) used for producing products for the military.

How Do I Get Certified? • Welding certification involves providing proof of qualification. This usually requires completing a hands-on performance test and sometimes a written test. • The welder performance qualification test determines a person’s ability to deposit sound weld metal with a certain process, material, and technique.

When and Where Can I get Certified? • Qualification tests can be taken at independent test labs or at the employer's facility. • The test will be for a specific application of the employer. • The tests are usually taken when the welder feels they are skilled enough to the test. • The level of skill required to a qualification test varies with the process.

Is There More Than One Type of Certification? • There are many types of certification to cover the numerous materials, processes, positions, filler materials, and codes. • There is not a single qualification test a welder can take that will qualify him/her for every situation encountered.

What Are Some of the Variables Involved in Certification? • The metal being welded may be mild steel, stainless steel, copper, aluminum or other metal. • The product form may be sheet, plate, pipe, castings, etc.

• The metal may be welded in the flat, horizontal, vertical or overhead position. • It may be welded with one of many different processes.

More on Variables • If changing one of the variables requires recertification, then it is known as an essential variable. • If there are several types of ts, positions processes, and materials in a weldment, the welder must qualify for each combination. • A person is generally qualified only for one set of variables at a time except that more difficult positions also qualify for less difficult positions, and thicker plates qualify for thinner plates. • Examples: – Qualification in the vertical and overhead positions qualifies a welder for all other positions. – Qualification for groove welds in one position qualifies a welder for fillet welds in the same position.

t Types • There are many types of weld ts used, but certification tests are usually done on one of a few standard fillet or groove welds. • The single vee groove is a very common t. If a certification test is taken on this type, it usually qualifies the welder for all fillet welds. A 3/8 thick single vee groove test plate with backing bar commonly used for AWS certification tests.

Position and Weld t Notation 1 = Flat 3 = Vertical F = Fillet

2 = Horizontal 4 = Overhead G = Groove

Examples: 2G = Groove weld in the horizontal position 4F = Fillet weld in the overhead position

Pipe Positions 1G = pipe’s axis is horizontal, pipe can be rolled. 2G = pipe’s axis is vertical, pipe is in a fixed position. 5G = pipe’s axis horizontal, pipe is in a fixed position. 6G = pipe’s axis is at 45° from vertical, pipe is in a fixed position.

What thickness must be welded? • The thickness of material that must be welded during qualification depends on the governing code. • An example from the AWS code is as follows: – If the test plate is 3/8 inch thick, the range qualified for is 1/8 inch to 3/4 inch.

Electrodes With manual shielded-arc welding, qualification with one electrode will also qualify a welder to use electrodes having the same or lower group designation. F1

F2

F3

F4

E6020 E6012 E6010 E7015 E7024 E6013 E6011 E7016 E7027 E7014 E7028

E7018

For example, if a welder qualifies with an E6011 electrode, he/she would also be qualified to use any of the other F3, F2, or F1 electrodes listed.

How are the Weld Specimens Tested? Some methods of testing weld qualification specimens include: guided bend testing, fillet weld break testing, macro etching and radiographic testing. NOTE: Additional testing requirements may apply.

Guided Bend Test • The guided bend test is used with the AWS, ASME, and API codes. It can involve face bends, side bends and root bends. It is a destructive method of testing welds. • Example /Fail Criteria The convex surface of the bend specimen shall be visually examined and shall have no discontinuity that exceeds 1/8 inch measured in any direction on the surface.

This image shows 2 guided bend test specimens that are acceptable.

This image shows a guided bend test specimen that failed.

The Fillet Weld Break Test • The fillet weld break test is a destructive test method where the specimen is bent over on itself. • Example /Fail Criteria The specimen shall the fillet weld break test if it bends flat upon itself. If the fillet weld fractures, the fractured surface shall show complete fusion to the root of the ts. It shall exhibit no inclusions or porosity larger than 3/32 inch.

The Fillet Weld Break Test (cont.)

These images show a fillet weld that ed the break test.

The Fillet Weld Break Test (cont.)

These images show a fillet weld that failed the break test.

Macro Etch Examination • Macro etching involves cutting the sample through the weld, polishing the surface, and using an etchant to examine the penetration profile and fusion of a weld.

Radiographic Testing • Radiographic (x-ray) testing is a nondestructive testing method. It uses penetrating radiation to form a radiographic image similar to dental and medical x-rays. • Example /Fail Criteria Welds shall have no cracks and no fusion type discontinuity that exceeds 1/8 inch for material up to 3/8 inch thick.

Radiographic Testing (cont.) • For progressively thicker material the size of discontinuity allowed generally gets progressively larger. • There are limitations on how close the discontinuities can be to each other. NOTE: Radiography cannot be used for examining ts welded by the short circuit transfer mode in gas metal arc welding. This lower amperage metal transfer mode may have lack of fusion that radiography may not show.

How Long Is a Certification Good For? • The length of certification varies with the code. • The AWS code requires requalification if a welder doesn’t work with a process for a period exceeding six months. This requalification requires welding a 3/8 inch thick plate. • Requalification is also required if there is a specific reason to question a welders ability.

What If a Welder Fails the Test? • The AWS code allows an immediate retest that consists of two test welds of each type that were failed and all the specimens must . • Another option is to have the welder complete more training or practice. This option requires a complete retest. • Retesting requirements vary with the code.

Summary • Certification is a process of providing written testimony that an individual is qualified to do certain work. • Welder certification is an important part of the overall quality process. • Certification requirements are specified by the standard, code or specification being used. • The certification process usually requires completing a hands-on qualification test and sometimes a written test. • Certification is specific to a particular set of variables and often welders are require to have multiple certifications.