Common Mistakes That Lead to Hydrogen Induced Cracking

Even when a qualified welding procedure is in place

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 […]

How to Determine the Shear Strength of a Fillet Weld

In our previous post we explained how to determine the strength of a transverse fillet weld.  A transverse fillet weld is one that is perpendicular to an applied load.  We will now look at how to determine the strength of a fillet weld under shear stress. If the load applied is not perfectly perpendicular to […]

How to Determine the Strength of a Transverse Fillet Weld

Unless you are a design engineer you typically don’t have to worry about determining the strength of a weld.  The strength of a weld refers to its load carrying capacity, or how much load it can handle before it fails.   However, it is very important for all of us involved in the welding process, from […]

How Hard is the CWI Exam?

Why passing rate is so low and what to do about it

Are you planning on becoming a certified welding inspector (CWI) in the near future?  Or do you need one of your employees to get this certification?  If so, you have probably heard that the exam is pretty tough.  Although the American Welding Society (AWS) does not publish information on passing rates, it is estimated that […]

What is Stress Relieving and Why We Need It

Stress relieving is a form of post weld heat treatment. In stress relieving we heat a material to a specific temperature; hold it at this temperature for a specified amount of time in order to reduce or eliminate residual stresses; and then cool it at a slow enough rate to prevent these stresses from redeveloping. […]

What is Post Weld Heat Treatment (PWHT)?

What is it? Why is PWHT needed? How is PWHT done?

Have you heard of post weld heat treatment (PWHT)? Of course you have. If you are involved in welding you have definitely heard this term.  But what is PHWT? When is PWHT required?  What temperature should PWHT be done at?  Heat treating of materials can be a very complicated subject, but when it comes to […]

Characteristics of Aluminum That Affect Weldability

If you have welded aluminum you know that it behaves considerably different than steel.  Other than the strength difference and general appearance, there are four physical characteristics of aluminum that make it weld completely different than steel.  These are: High thermal conductivity High solidification shrinkage High hydrogen solubility Oxide coating When welding aluminum it is […]

7 Variables That Affect Weld Penetration

Getting deeper penetration, or at least adequate penetration is very important in welding.  There are a few applications in which we wish to minimize penetration, but in general we always want good penetration.  There are many variables that affect penetration, some more than others.  It is important to know how each individual variable affects the […]

Bigger (Weld) Is Not Always Better

When it comes to fillet welds, bigger is not always better.  A fillet weld is easy to measure, simply take out your fillet weld gauges measure it.  However, there is an incorrect assumption that a bigger weld (as measured with a fillet gauge) is always stronger than a smaller weld. Before we get into this […]

5 Methods to Determine Preheat Temperature

Preheat is used when a base material, due to its chemical composition, thickness or level or restraint, is susceptible to cold 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 be playing it […]