Steps to determine if welding preheat can be eliminated?

Testing the effects of preheat in small parts and assuming it will be the same on large sections is a mistake.

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 […]

Factors Affecting Cooling Rates of Welds and Heat Affected Zones

Different ways to manage the rate of cooling

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 […]

Why More Customers are Requiring Qualified Welding procedures

If you own or work at a job shop you may have noticed an increase in the number of customers that require the use of qualified welding procedures to build their products. Some fabricators are even getting this request from long time customers who never required them in the past. So why is this? The […]

Which Arc Welding Process is the Most Efficient?

This question can be answered very quickly.  Gas Metal Arc Welding (GMAW) and Submerged Arc Welding (SAW) can have 98-99% deposition efficiency.  However, the question is a bit more complicated since when we talk about efficiency we don’t just care about deposition efficiency (how much of the electrode becomes weld metal).  What we care about […]

Causes of Porosity in Submerged Arc Welds

Submerged arc welding is typically done automatically, meaning it is not done by hand, but rather set up as hard automation.  The operator simply controls the welding machine and torch position to obtain the desired results.  Typically,the system is run by an operator, not a welder.  So when problems come up, the operator may not […]

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. […]

Effects of Voltage on Weld Quality

Voltage is one of the most important variables in a welding procedure.  It is also one that is sometimes misunderstood.  You may ask five welders what effect voltage has on a weld and you may get five different answers.  This is because voltage can do a lot of things, some good and some bad. Understanding […]

Welding Engineering Topics for Non-Welding Engineers

Today we are faced with a tremendous shortage of welding professionals.  This includes welders, fitters, cutters, inspectors, supervisors, robotic technicians and welding engineers to name a few.  Although every fabricator can benefit from having a welding engineer on staff, most welding engineers tend to work in specific industries such as Oil & Gas, Aerospace, Automotive […]

Why Welds Fail: It’s never one thing

Weld failures happen all the time.  Some are more serious than others in terms of cost and potential for property damage and bodily harm.  If a weld failure is considered serious it typically gets a lot of attention. Forensics labs and industry experts get called to determine the root cause of the failure.  It may […]

Using the Carbon Equivalent Method to Determine Weldability of Steels

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 […]