21 Changes to PQR Essential Variables that Require WPS Requalification

​Have you ever seen a welding procedure specification with established amperage ranging from 200 to 550 amps? Or voltage ranging from 21 to 29 volts? Or some other variable with a huge window? This is all too common, but extremely dangerous. Why? Because changes to essential variables beyond that which is reasonable will affect the […]

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 […]

Non-Value Added Activities Affecting Welding Costs

Many fabricators struggle to get a grip on their welding costs.  The best they can do is try to find suppliers that will sell them their consumables, gas and other raw materials at a lower price.  Those who try to reduce costs by being more efficient soon realize that simply speeding up welding is not […]

Why is Preheating Necessary?

Preheating steel before welding is common practice. Sometimes we apply heat after we are done welding as well. Other times we apply heat between passes to maintain the minimum interpass temperature.  Many use preheat simply because it is written in the WPS, but not really understand why it is necessary.   Preheating is used for […]