Distortion caused by the heating and cooling cycles of welding is extremely problematic. It can place structures out of dimensional tolerance creating costly rework. In some cases parts need to be scrapped. Understanding the causes of distortion and the properties of the metal being welded are an absolute necessity for those managing welding operations. There […]
Have you ever noticed that there are design rules that prohibit sizing a fillet weld below a certain size for a given thickness of material? If you look at AWS D1.1/D1.1M:2020 Structural Welding Code (Steel) you can find this on Table 7.7. If you happen to own a copy of AISC 360-16 Specification for Structural […]
Preheat is used when a base material, due to its chemical composition, thickness or level or restraint, is susceptible to cold cracking (hydrogen induced cracking). Knowing what temperature to preheat your base metal is sometimes a complicated matter. You may hear people say “preheat to 300F to be safe.” The reality is that 300F may […]
Competition amongst manufacturers of welding machines is a wonderful thing. Companies like Miller, Fronius, OTC, Lincoln Electric, and many others are continuously improving their equipment, making it more user-friendly and at a lower cost. We as users benefit from this. However, this has brought about a big problem. And that is the belief that we […]
Today we’ll cover 5 more very important concepts that are governed by the AWS D1.1 Structural Welding Code (Steel). If you missed our last post with the first five questions simply click here. These concepts can show up as questions in the Certified Welding Inspector (CWI) Exam. As stated in our article from last week, […]
Heat input is important because it has an effect on cooling rates which in turn can significantly affect the mechanical properties of the weld and heat affected zone. It also plays a role in susceptibility to distortion. High heat input can be beneficial in some cases and detrimental in others. A common misconception is that […]
As discussed in our previous article, and many times in the last 50 or so, preheat is necessary in steel welding to control the cooling rate. More specifically, preheat is used to slow the cooling rate down in order to prevent excessive hardness in the heat affected zone (HAZ) which can lead to cracking. Before […]
Our next article will discuss a question we are asked quite often: Can we eliminate preheating before welding? Preheating is necessary to slow the cooling rate down after welding which in turn avoids excessive hardening of the weld and heat affected zone. Eliminating preheat can lead to hydrogen induced cracking and catastrophic failure. A […]
It is often incorrectly assumed that quenched and tempered (Q&T) steels are hard to weld or even completely unweldable. This assumption is inaccurate as most Q&T steels have great weldability. However, extreme care must be taken to prevent cracking or loss of certain mechanical properties. A very common quenched and tempered steel is ASTM A514. […]
Waveform control is the ability of a welding power source to affect heat input, droplet shape and size, penetration, bead shape and toe wetting by the use of microprocessor controls which manage the welding output. Advances in waveform control technology over the past two decades have provided the ability to weld tough materials successfully. One […]
