It has been said that “A bar of iron costs around $5. Made into horseshoes it’s worth is $12, made into needles its worth is $3,500, made into balance springs for watches, it’s worth is $300,000.” The value of steel to humankind over the millennia has been immense.
As its raw material (iron ore) is abundant throughout the earth, steel is copiously manufactured around the world into sheets and bars of numerous alloys for myriad applications. In this commodity form, its value fluctuates with economic and market forces. Converted to precision instruments or architectural masterpieces, it’s material value becomes priceless.
The point here is that understanding the metallurgy and the properties behind different grades of steel adds tremendous value when designing any type of steel application. Whether for “red iron” building construction or a grand staircase with ornamental rails gracing the finest custom home in your portfolio, specifying the right kinds of steel is fundamental to a successful project.
Why use steel instead of more exquisite metals?
Just to be clear, we love to work with bronze and other metals when called for and don’t want to sound like steel industry advocates. We can all be thankful for what steel has enabled humankind to accomplish over the millennia. And it isn’t the existence or discovery of steel but the knowledge of how to use it that has made possible everything from architectural wonders to space flight. Let’s explore how this relates to our work with architectural metals.
Dollar for dollar, steel’s properties are unmatched by other materials for strength and other manufacturability characteristics. Alloyed in various ways, steel can be made harder and stiffer or more bendable and malleable while maintaining very high tensile strength. It can also be made extremely corrosion resistant (“stainless”) for marine, severe weather and other harsh environment uses. We should also mention that steel can be finished and polished to sparkle and shine or even reflect like a mirror.
Make steel conform to your desired aesthetic look.
The right choice of material for your job makes all the difference in how successful the final outcome will be. A prime example is knowing when to use either hot rolled or cold rolled steel and it depends on a few factors including the finished look you want.
Are you looking for either an industrial or a rustic look? Hot rolled steel is generally a better choice with it’s rougher finish. If you want a more modern look with more crisp and precise edges or finer finishes, cold rolled steel will work best.
You also need to know the differences in finishing techniques for hot and cold rolled steel. Hot rolled material often needs to be sandblasted before finishing, while cold rolled material may be sanded only or sandblasted. This choice can make a big difference when powder coating, electrostatic plating, electroplating, or applying a patina finish.
Very often, different building components are manufactured from bars and plate from different sources that must be mated and have the same look and finish. As you can see, understanding how to “dress” the different steel parts to aesthetically match is critically important in architectural, miscellaneous and ornamental metal work.
Now let’s take a close look at the major differences between hot and cold rolled steel.
Rolling the steel at a high temperature (typically over 1,700° F), which is above the steel’s recrystallization temperature, allows it to be formed and shaped more readily and the parts can be made in much larger sizes. The surface may have pitting from the rolling process with a rougher finish. Hot rolled steel takes less time to produce and is typically cheaper than cold rolled steel. Consider hot rolled steel for:
- Structural elements and large components
- The industrial, rustic or “railroad track” look & finish
- Situations that don’t require high fabrication tolerances
Cold rolled steel is processed further in reduction mills where the metal is cooled at approximately room temperature. This is followed by what’s called annealing or “tempers rolling” which produces steel with tighter dimensional tolerances and broader options for surface finishes. For aesthetics and precision, cold rolled materials offer several advantages.
- The products boast a finer surface finish.
- Cold rolled metal is superior in precision tolerances, concentricity and straightness.
- Use cold rolled for areas where tight tolerances, polished surfaces and fine edges are required.
To sum up our thoughts on working with architectural steel, we offer this. Think about why steel has only increased in use over the centuries as the choice material in industry, from railroad tracks and I-beams to precision motion devices and tiny spring mechanisms. Then use your imagination to use steel in diversified ways to help strengthen and distinguish your most inspired designs.