19.1 History of Inspecting Welds
David Colameco, M.Ed.
Protecting public safety
Unfortunately accidents happen that result in the loss of life, permanent disfigurement, and/or loss of quality of life to both fabricators and the public at large. The Welding Codes chapter of this book discusses that laws, regulations, and codes are written after serious injuries or fatalities have occurred. That chapter of this book discusses how codes are typically written by groups of experts from industry, government, and research institutions. Due to this expertise contained within the welding codes, many state and federal lawmakers have mandated the use of welding codes to ensure a minimum level of workmanship in fabrications that could kill or injure the public.
As part of each welding code, inspection requirements are included to provide inspectors the means to determine if the quality requirements have been met. While meeting these requirements will not prevent all in-service fabrication failures, they will help prevent them because these codes contain rules based upon lessons learned from failures.
Enhancing fabrication quality
Welding codes provide the minimum standards for fabrications. Many companies will fabricate to higher standards for increased durability and quality to meet customer expectations. Truck companies may test their trucks in scenarios where the fabricated parts are exercised to simulate years or decades of use. When failures occur during testing, manufacturers may improve the design to avoid costly warranty claims and/or to advertise an expected lifetime that is longer than their competitors.
Failures can also be identified when a customer returns a product, or with today’s social media, when customers post about failures online. Companies can then request the failed product for inspection and interview the customer to determine what in-service conditions the part encountered. If inspection of the product finds that a particular weld is repeatedly failing for example, then the company may tighten inspection criteria on that weld if it is found that fabrications with undersized welds were sent to customers. Inspection serves as a great way to quantitatively measure and determine causes of failure.
Welding steps to enable successful inspection
As a welder and fabricator it is important to know how the inspection will be carried out and if the inspection requires a certain level of workmanship. A great example of this is the need to remove spatter from the surface of the base metal for magnetic particle testing. If pieces of metal in the form of spatter are on the surface, they will interfere with the test. Likewise, ultrasonic testing usually involves an inspector sliding the transducer across the surface of your weldment. It is important that the transducer sends ultrasonic waves at specified angles into the material being inspected. If spatter exists on the surface of the weldment, the transducer may not be able to be placed properly.
When reading a blueprint, the inspection method will usually be placed in the tail of the welding symbol. If you are not familiar with the abbreviations in the tail of a welding symbol on a print you are working with, please ask a coworker or your mentor about the symbol and any requirements. Take careful notes in a small fabricator’s notebook so you don’t forget what others tell you and to avoid asking the same questions every few months.
Used in this book as shorthand for welding codes which are documents that specify the requirements for welding. Codes become mandatory when included in contracts, by law, or other legal mandate.
An electronic piece of equipment that both emits and detects sound waves. It converts an electrical signal to a sound wave when transmitting and converts sound to an electrical signal when detecting sound waves.