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 […]
One of the dangers we should be aware of when welding high strength steels or even thick sections of low carbon steel is hydrogen induced cracking. Hydrogen induced cracking, also called hydrogen assisted cracking and cold cracking, is caused when three conditions are present. First, we need a susceptible microstructure (base material related). Second, we […]
A prequalified welding procedures specification is a welding procedure that is exempt from the qualification tests required by a code or standard. Not all codes provide the user with the advantage of using prequalified welding procedures. Some that do are: AWS D1.1 Structural Welding Code – Steel AWS D1.3 Structural Welding Code – Sheet […]
The qualification of welding procedures is necessary to ensure that the selected welding parameters can produce sound welds. Qualification typically involves a combination of destructive and nondestructive testing. When a particular code, such as AWS D1.1 or ASME Section IX is used, the code will dictate the type and numbers of tests necessary in order […]
Developing, or writing a welding procedure, goes far beyond setting up amps and volts. It entails the selection of many variables which fall under the 9 required components of welding procedure specifications we discussed last week. Today we look at those 9 components again, but rather than just stating what they contain we explain how […]
Regardless what position you hold, if you work in the welding industry you have heard of welding procedures specifications (WPSs). To some, a welding procedure simply means the selection of a few variables such as amps and volts. To others, these are the documents that govern all welding done in their facility. A […]
Controlling weld quality is not always an easy task. Many fabricators struggle to manage the amount of rework, the discrepancies from one batch of product to the next, and the varying levels of productivity and workmanship amongst their welders. This inability to control weld consistency is not surprising. Welding has more than 20 variables that […]
Many fabricators can lower their welding costs significantly if they paid close attention to weld sizes. If a print calls for a ¼” fillet weld and in production you make a 5/16” fillet weld, you are overwelding by 56%! If the print calls for a 3/16” fillet, the 5/16” fillet weld you deposit would be […]
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 […]
