Hot Rolled Steel: How it is Made

Hot Rolled Steel SheetHave you ever wondered how different things are created? How a semi-truck is produced or what your water heater is made out of? If you are anything like me, this is a daily occurrence. The likely answer is that it started in a rolling steel mill in the form of a slab of unfinished metal and was worked into a hot rolled coil.

How Hot Rolled Steel is Made

Hot rolled steel is the most basic carbon steel product mills produce. It is used to manufacture products in which the surface finish is not critical, including automotive, truck frames, water heaters, agriculture equipment, compressor shells, guard rails and the list goes on.

The Heating Process

The process in which hot rolled is produced begins with heating slabs of steel to approximately 2,300 degrees Fahrenheit. The amount of heat directly affects the properties of the steel. Meaning, if the temperature is not high enough it can cause defects in the material. This is likely due to carbides (compound of carbon) and nitrates (polyatomic ion-an even more complex term) not fully dissolving.

When the hot material is being transferred from the furnace it reacts with the oxygen in the air. This reaction forms a mill scale or a flaky surface of iron oxides. The mill scale can affect the surface quality of the hot rolled steel if left alone. To remove the iron oxides the material is then sent through a mill scale cleanse. It is sprayed with high pressure water (much higher than your power washer at home).

Rolling Mill and Stands

The cleansed material is then sent through a rolling mill and is rolled from a thickness of roughly nine inches to an inch. The process consists of a series of four to five stands (set of rollers) that decrease the thickness and increase the length by horizontal rolls. The material is also squeezed vertically to control the width.

At this stage the material’s ends are sheared to create a transfer bar. The transfer bar is sent through another series of stands to further reduce the thickness to the desired sheet gauge.

The Cooling Stage

The flat-rolled steel is delivered across a runout table that consists of cooling sprays. The cooling rate may be modified for each strip to create the desired properties of the coiled end product.

After the material is cooled it enters coilers. Once coiled, the product is ready to be delivered to service centers, like OFR Metals, for further processing. It may also be delivered straight to fabricators.

The hot rolled material can also endure additional processes, including pickle and oiling, cold rolling, and other coatings.

The process of creating hot rolled steel sheets is much more interesting with visuals. Check out this great video to learn more about the hot rolling process.

New Outside Sales Representative for Kansas

The O’Neal Flat Rolled Metals (OFR Metals) New Century, Kan., branch recently welcomed Evan Skinner as the new outside sales representative.

Skinner comes to OFR Metals with both inside and outside sales experience as well as experience in fabrication sales. He is a graduate from the University of Kansas.

“We look forward to working with Evan,” said Mike Severin, general manager for the OFR Metals Midwest Region. “I’m confident he will be a valued contributor to our growth strategy in the Midwest.”

June ONI Insight: Market Indicators

The U.S. economy was negative for the first quarter of 2015. Leading the decline was gross domestic product which fell 0.7% in May. As we recently saw, the strong U.S. dollar is most likely to blame, along with cold weather and the West Coast port strike.

There is an upside, however. The U.S. economy is showing signs of growth. Housing starts increased by 20.2% in April, its best monthly gain since 1991. The U.S. also added 280,000 new jobs in May, up from the revised April number of 221,000.

The U.S. steel industry is showing confidence that there would be support in the House of Representatives to pass trade remedy improvements. The American Trade Enforcement Effectiveness Act would include provisions to strengthen current trade remedies, including anti-dumping and countervailing duty measures. However, we are still seeing excess steel capacity worldwide particularly in China.

For more information on what is happening in the metal market view the ONI Insight June 2015 below.