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How Are Microalloyed Steels Made?
First, you need the right chemistry—one that has the desired tensile properties with the correct thermomechanical processing. At Charter Steel, we’re proud to develop and trial specialized chemistries that create stronger steels with higher yield points.
Second, it’s necessary to have tightly controlled rolling parameters. As your steel partner for microalloyed solutions, we have the following mill capabilities available to you:
- Walking beam furnace: Minimizes decarburization on the billets; ensures uniform front-to-back billet temperatures for consistent final properties of rolled coils
- Water cooling zones: Provide superior temperature control; ensure the product has a fine, uniform grain structure and thinner, more uniform scale
- Morgan no-twist mill: Offers the capacity for products to be rolled with diameters as small as 5.5 mm (0.219”)
- Reduction through intermediate mills and process gauging: Holds consistent tolerances during rolling and lets processors perform real-time quality control at low temperatures
- Cooling conveyor: Allows rolled coils to be cooled in a controlled manner; creates steels with uniform mechanical properties
How Is This Grade Of Material Cooled Evenly?
A Stelmor cooling line distributes more air to the edges of the coil (the denser portion) and less to the center. Cooling fans minimize the amount of tensile variation within the rings by forcing air to the edges of the coils and allowing the rings to cool more uniformly around the circumference.
How Does Conventionally Heat Treated Steel Compare To Microalloyed Steel?
The precipitation hardening effect of strong carbide forming elements (i.e., vanadium, columbium) coupled with tight compositional control and tensile controlled rolling are required in microalloyed steels to achieve mechanical properties similar to other types, such as conventional quench and tempered steel. Microalloyed technology often leads to reduced energy use through the elimination of final bolt heat treatment and, overall, a more efficient process.
How Are Microalloyed Steels Evaluated?
A comprehensive evaluation of rolled coil is performed to determine which rolling condition provides optimal mechanical properties. For example, for a bolt application, the tensile evaluation would involve taking 208 tensile samples and rings would be cut at 26 locations, then cut at wraps from the front and back of each coil. From each of these rings, eight tensile samples would be cut for testing.
Why Are Microalloyed Steels Sought After?
Microalloyed steels are incredibly strong and ductile and have excellent weldability and wear resistance. Ductile steels are more likely to stretch (versus break), giving the end user the ability to do more with the product, like drawing it out into thin wire.
Which Industries And Applications Are Microalloyed Steels Best For?
Though microalloyed steels are frequently used for automotive and construction applications, steel experts can develop ideal chemistries for almost any application and industry, including energy, shipbuilding, heavy equipment, rails and offshore/platforms.
We Develop, Test And Prove Unique Steel Chemistries That Meet The Strictest Requirements
At Charter Steel, delivering clean, strong steel is our passion. We’ll work closely with you to understand your application, conduct trials, generate thorough reports at our state-of-the-art lab and fine-tune rolling mill parameters to accurately align with your specifications.
Recently, we engineered a custom chemistry for a manufacturing company in the construction sector. Our solution is 20% stronger and maintains a higher yield point, ensuring that when their fasteners hit their maximum load, they can stretch further before reaching their breaking point. This will lead to safer structures in the customer’s seismically active region.
Let’s make stronger steel together.
Contact us at Commercial@CharterSteel.com.