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 […]
Abrasion resistant (AR) steel plate is used in applications requiring abrasion and impact resistance. It is alloyed with high levels of carbon in order to attain high levels of hardness through the quenched and tempered process. AR plate is primarily used in conveyors, buckets, dump liners, construction attachments, grates, body armor and ballistic plates. AR […]
We received a large number of email responses and comments to our article from two weeks ago pertaining to weld quality standards. The main question was how to do you determine the minimum level of quality for your products, but also how do you verify you are reaching or exceeding that quality level. Responses […]
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. […]
Last week we had the pleasure of working with a fabricator of pressure vessels in order to help them reduce manufacturing costs. As mandated by the ASME Boiler and Pressure Vessel Code this fabricator had welding procedure specifications (WPSs) and procedure qualification records (PQRs) in place. These were properly written, tested and documented. The WPS […]
Not all weld discontinuities are weld defects, but all weld defects are discontinuities. Understanding the difference will let you know if you need to scrap a part, repair it or simply add more weld. There are many codes depending on what type of product you are welding on. The codes are used as guidelines by […]
Can our selection of shielding gas affect the strength of a weld and other important mechanical properties? Absolutely! The difference is more pronounced when using flux-cored (FCAW) wires than when using mig (GMAW) wires, especially as the wire’s tensile strength goes up. Although we can affect strength by using different gases, what we should be […]
