It is not uncommon to find fabricating shops that are welding a variety of metals including carbon steel, stainless steel, aluminum and nickel alloys. In many cases some of these materials need to be welded to other types. Once very common situation, especially in automotive applications is welding carbon steel to stainless. One of the […]
Preheating of structural steels is carried out primarily to slow the cooling rate after welding and prevent the formation of martensite. Martensite makes the weld and the heat affected zone (HAZ) very hard and brittle. This newly formed microstructure is susceptible to cracking. By slowing the cooling rate we reduce or eliminate the formation of […]
The most widely used welding code in North America, and perhaps the world, is AWS D1.1/D1.1M Structural Welding Code – Steel. It is specified as the quality standard in hundreds of contract documents every year. Yet, we find that less than half of the fabricators that need to use it have a sound understanding of […]
Cracks on welds are never good. Welding codes always have allowances for porosity, undercut, weld sizes, and even weld profiles. However, there is never an allowance for cracks. Being a linear discontinuity, a crack will tend to propagate through the weld and into the base metal with relative ease, especially in cyclically loaded structures. So […]
When it comes to precision welding and fabrication, it only takes one wrong document to cause a major problem. Still, many companies operate by the motto: “if it ain’t broke, don’t fix it”. Assuming you have incredible attention to detail and a lot of luck, that approach might work for a while. That’s why companies […]
Stainless steels are iron based alloys that contain a minimum of 10.5% chromium. This chromium reacts with the air and forms a very thin but very tenacious chromium oxide layer which is what prevents stainless from rusting. There are 5 types of stainless steels which are categorized depending on additional alloying elements. One thing they […]
Knowledge of welding symbols is not a requirement limited to welders. Many other professionals must have the ability to interpret and write welding symbols. From estimators to designers to quality personnel, this universal language must be understood. In our last post we touched briefly on the importance of being able to interpret welding symbols. If […]
Welding symbols are the universal language of the welding industry. They are used to communicate vital information regarding the details of a weld including: Joint details Weld size and length Weld sequence Contour finish Location Process Required inspection methods Penetration requirements Etc. Yet this important language is not understood by the vast majority of those […]
Hydrogen Induced Cracking (HIC), also called hydrogen assisted cracking (HAC) and cold cracking, is a common welding defect when welding heavy steel sections and steels with high carbon content. If you would like to learn more about the causes of HIC read Factors Influencing Hydrogen Induced Cracking. In the above mentioned article we explained that […]
