Welding: What’s really happening behind the mask?

By J. Craig Martin

Mention welding and the most common picture that appears in a person’s imagination is of the solitary welder behind a mask with a bright bluish, whitish light shining brilliantly around them. But what’s really happening behind all those arcs and sparks? Welding is a ubiquitous operation in the manufacture and construction of everything from consumer goods to vehicles and bridges to processing plants. Yet, despite its wide range of application, few understand what is really going on “behind the mask.”

Welding is one of the most flexible and adaptive joining technologies that exist today. It can join materials from less than one millimetre in thickness up to hundreds of millimetres thick and can be used to join steel, aluminum, copper and almost anything you can think of.

The science of welding touches on a wide range of disciplines, electrical, metallurgical, thermodynamics and more. Suffice it to say, welding can be complex and requires real expertise to ensure it is done both correctly and safely. Like many industries, the use of standards to control the operation of welding is critical.

History

Canada enjoys a long history of world-class standards in the discipline of welding, and our excellent track record in safe welded infrastructure is due in large part to these standards. Canada has two distinct sets of standards as it relates to welding:

• For boilers, pressure vessels and pressure piping, the normal standard that is used is the Canadian Standards Association (CSA) B51 “Boiler, pressure vessel, and pressure piping code.” This is an adoption of American Society of Mechanical Engineers Section IX “Welding and brazing qualifications.”
• For structures, machinery and other non-pressure applications, the CSA “W” series of standards is normally used. The most common CSA welding standard in use in this area is CSA W47.1“Certification of companies for fusion welding of steel.”

Although similar in some ways, the two sets of standards are very different. They have been developed for very different types of products that have very different performance expectations once in service. It is critical for owners, engineers and other specifiers to understand what standard(s) is applicable for the project at hand. It is not a matter of one standard being better than the other; rather it is selecting the right standard for the right product and service conditions.

Welding in the pressure vessel/ piping area is normally regulated at a provincial level by government agencies such as the Alberta Boiler Safety Association or the Technical Standards & Safety Authority. Although the base standards noted previously are the same across Canada, each agency may have a slightly different approach as to how the standards are implemented. Non-pressure standards, on the other hand, are the same all across Canada.

There are several CSA standards that may be used, the choice typically dependent on the material being welded. The Canadian Welding Bureau (CWB) is the national certification body that oversees the application of these standards. As noted previously, the most common CSA welding standard used in Canada is CSA W47.1 “Certification of companies for fusion welding of steel.” This standard applies to a wide range of applications: structures, buildings, bridges, machinery, equipment, cranes, tanks, non-pressure piping and antenna towers, to name a few.

CSA W47.1 is a company certification standard and is intended to provide assurance that the company has all the components in place to produce a sound weld. The standard is based on the understanding that there are three key components that must be in place to en- sure a sound, high quality weld:

1. Competent people making the welds (the welders).
2. A proven recipe for making the welds (the welding procedure).
3. Competent shop floor and engineering staff (the welding supervisor/engineer).

All these components are of great importance and a welding company cannot claim to be certified to CSA W47.1 unless all three are shown to be in place. A great weld results from more than just the skill of the welder. Although this is an important element, the welder must also know what they are welding and how to weld it. This is where the welding procedure comes into play. Training, supervisory and engineering personnel must also control the entire welding operation. There is  risk of a poor quality weld if any one of these elements is missing.

An additional method to ensure high quality and safe welds is the concept of an independent third party to confirm that those welding companies that choose to become certified do, in fact, meet the key requirements of the certification standard. This is where the CWB comes in. When the first CSA W47.1 standard was introduced in 1947, the industry agreed that a single body should be formed to administer the standard.

The Canadian Welding Bureau

The objective was to create a level playing field by ensuring consistent application of the stated requirements. This would in turn help guarantee that welded structures were of high quality and safe. In response, the CWB was formed as a non-government, not-for-profit, industry funded organization, acting as an independent certification body for the welding industry. Its primary mandate, however, is the protection of public safety.

Since its creation, the CWB has expanded its role within industry, managing multiple CSA welding standards for fabricators, inspectors and welding consumables. Today, there are over 6,500 companies certified by the CWB in over 20 countries around the world. To prove competence in the practical application of welding, individual welders must undergo regular testing. This is normally done every two years and welders are examined on each welding process, welding position and joint configuration for which they wish to be qualified. All testing is witnessed by the CWB and documents of certification are issued.

For welders to know what they are welding and how to weld it, a procedure must be created by the company. This lists all the variables that may impact the final quality of the weld. The material grade, the filler metal, the welding parameters, the required preheat and many other variables must be defined in what is essentially a recipe for making the weld. These procedures are created by the welding supervisor and/or engineer and then independently reviewed by the CWB for compliance to applicable standards. Certification is not a one-time event. All organizations that are certified to CSA W47.1 must continually comply with the requirements of certification, ensuring that new welders are proven to be competent and that new welding procedures are developed for new projects that they undertake. In addition, the CWB continually monitors the activities of certified companies providing on-site audits of the welding operation at least every six months.

As a not-for-profit certification body, costs to industry are kept low, with the typical Canadian fabricator’s certification fees set at less than $2,500 annually. Certification brings many benefits to both the welding industry, and the specifiers, owners and end users. The welding industry has realized cost savings as they leverage certification to man- age quality issues and reduce rework and client complaints.

For the end user, specifying certification can help reduce risk of poor quality or failure. For some product types, certification is mandatory under regulatory requirements or product safety standards. Buildings, bridges, cranes, platforms, railings and stairways are some of the product types where certification is mandatory for the welded fabricator. Where certification is not mandatory, many owners choose to require certification by their suppliers or subcontractors as an extra assurance for quality and risk reduction.
J. Craig Martin is with the Canadian Welding Bureau. This article appeared in ES&E’s November/December 2014 issue.