December 11, 2003
Welding can severely influence strengthened or hardened metals, depending on the hardening technique used. Because of this, post-weld heat treatment is often very helpful in maintaining weld joint strength because it softens or tempers any martensite or bainite that formed in the HAZ.
October 9, 2003
When it comes to modifying a steel's strength and hardness, it's important to not confuse hardness with hardenability and remember that hardenability characteristics are important because they help identify how much a specific steel will harden during welding.
August 28, 2003
Steel classification is important in understanding what types are used in certain applications and which are used for others. For example, most commercial steels are classified into one of three groups: plain carbon, low-alloy, and high-alloy. Steel classification systems are set up and updated frequently for this type of information.
June 26, 2003
When you heat or cool a piece of metal to a specific temperature, that metal goes through what's called a phase change, in which its crystal structure changes. Sometimes the change is obvious. For example, when a piece of metal melts, it goes through a phase change when the crystal structure breaks down and the metal goes from solid to liquid. When it solidifies it's also a phase change, as the structure re-forms from liquid to solid.
February 27, 2003
Talk about a can of worms ... From crystalline structures to phase diagrams and interstitial solutions, from microstructures to allotropic transformations, it sometimes seems that for every question metallurgy can answer, for every problem it can solve, it creates two more.