Preheat is necessary in certain carbon and low alloy steel applications to prevent hydrogen induced cracking, also known as cold cracking. Cold cracking susceptibility increases as the amount of carbon in steel and the thickness go up. The higher the carbon content the easier it is for the steel to harden. And, the thicker the […]
High carbon steels are those containing 0.45% carbon or higher. They are typically considered “hard to weld” because they are crack sensitive and are susceptible to undergoing significant changes in their physical and mechanical properties after welding. However, high carbon steels can be welded successfully and without problems by having a sound understanding of the […]
The use of prequalified welding procedures has many advantages as well as many disadvantages. One danger of using prequalified welding procedures is that AWS D1.1 allows for quite a bit of freedom in weld sizes. If you look at Table 5.1 –Prequalified WPS Requirements of AWS D1.1/D1.1M:2020 Structural Welding Code (Steel) you’ll see that in […]
The AWS D1.1 Structural Welding Code (Steel) welder qualification plate tests consists of a groove weld with a 45-degree included angle. The plates are prepared to a knife’s edge and a ¼ in [6 mm] backing strip is used. The test for unlimited thickness will use plates that are 1 in [25 mm] thick. Anything […]
In our previous article we mentioned that a customer was inquiring about running their 98% argon / 2% carbon dioxide (98/2) shielding gas on mild steel. This gas is used on stainless as it maintains the amount of reactive gas (in this case CO2) under 3%. Our quick answer was “yes, you can weld carbon […]
The qualification of welders and welding procedures often involves macro-examination of welds. Performing macro-etches is a relatively simple procedure, but strict guidelines must be followed to ensure safety. Most chemicals used in etching solutions are hazardous and must be handled accordingly. Any person etching with these chemicals must familiarize him or herself with the corresponding […]
Our previous article discussed the importance of having a specification for weld quality. In this article we’re talking about the importance of one of its basic components: Welding Procedure Specifications (WPSs). Many fabricators don’t have WPSs. They rely in the experience of their welders to select the right parameters. As much as we want every […]
If you have been reading our articles for some time you know how strongly we feel about having documented welding procedure specifications which have been qualified by testing or prequalified in conformance with code requirements. Yet when we recommend that these very important documents be developed and used in production we get a lot of […]
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. […]
If you have ever been tasked with selecting the right specification and grade of steel for a particular application you know there are hundreds of choices. Typically these are based on the materials tensile strength and yield strength. There are many factors that go into selecting the right base metal for a given application. In […]
