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 […]

7 Ways to Eliminate Porosity in Your Welds

Porosity is a weld discontinuity that is not as detrimental to structural integrity as cracks, undercut, overlap and lack of fusion. However, it is unsightly and when painted it looks absolutely horrible. Because it does not have sharp ends, porosity does not propagate like a crack. The reason why there are limits to the amount […]

Benefits of Using Prequalified Welding Procedures

Prequalified welding procedures are a great tool available to those who need qualified procedures in conformance with  AWS D1.1 Structural Welding Code – Steel.  However, there are strict requirements for the use of a prequalified welding procedures.  It is not as easy as picking a qualified joint and using filler metal manufacturer’s recommended procedures. There […]

5 Common Mistakes Made Welding Stainless Steel

Most types of stainless steels have good weldability and can be welded with all arc welding processes (GMAW, FCAW, GTAW, SMAW and SAW).  This is both good and bad.  It’s good because it makes fabrication possible, but it’s bad because most assume it can be welded just like carbon steel. In fact, this is the […]