5 Things about Steel Processing You Need To Know

Steel ProcessingThe majority of modern demolition projects recycle scrap metal. Why? Because it’s a lucrative salvage material. By removing and recycling or selling scrap, demolition contractors can offset deconstruction costs. Scrap metal demolition requires removal from structures, extraction from concrete, and collection of scrap metal—steps we’ve covered in previous posts. Today we’re going one step further, reviewing five key concepts about steel processing, in which scrap metal is converted into usable steel.

Scrap Metal Demolition: 5 Key Concepts in Steel Processing

1. Steel Production Methods have Improved Greatly Over Time. In the middle ages, steel was only created in small quantities, because the production process was extremely time consuming. Steel could not be used for construction until Henry Bessemer discovered the eponymous Bessemer process in the early 1850s. Prior to that time, there was no quick, cost-effective way to reduce the amount of carbon in pig iron. Pig iron is produced by smelting iron ore with fuel, such as carbon-based coke. Too much carbon makes an iron alloy too brittle and rigid.

Before the Bessemer method, steel was produced over the course of a week using the cementation process. This procedure required huge amounts of coke—3 tons of coke for every ton of steel produced. The cost of coke made steel very expensive—around $6500 for a long ton. Bessemer discovered that exposure to oxygen removed impurities such as carbon, silicon, and manganese; these materials escape as gas, or are separated into a solid slag. Far less coke and time was needed to create steel using the Bessemer method, so the price of steel soon dropped to about $820 per long ton. This drop in price allowed steel to be economical for architectural applications.

2. There are Two Primary Modern Steel Making Methods: BOS and EAF
During Bessemer’s time, steel was made in an open-hearth furnace. Today, however, steel is generally made using Basic Oxygen Steelmaking (BOS) or an Electric Arc Furnace (EAF). The BOS furnace works about ten times faster than an open-hearth furnace. In a BOS furnace, purified oxygen is blown through the molten pig iron. EAF units use electrodes to create extreme heat—so extreme that cold scrap metal may be used. The BOS method uses between 25% and 30% recycled steel; EAF steelmaking can use nearly 100% recycled scrap steel. In general, the BOS technique creates more malleable steel, which is often used to make tin cans, car fenders, and other objects that require cold working. EAF steel is used for items that need little cold working, such as plates, reinforcing bar, and structural beams.

3. Different Metals May be Added to Steel to Generate Unique Properties.
Chemical cleaners called fluxes may be used in partnership with the methods described above to remove impurities such as sulfer, phosphorous, and manganese. Once the steel has been refined in this way, various metals may be added to provide unique characteristics. For instance, stainless steel is created by adding 10-30% chromium. Adding chromium and molybdenum, on the other hand, creates chrome-moly steel, known to be light and strong.

4. Stainless Steel may be Finished with Colors and Textures for Architectural Uses.
Once stainless steel has been created, it may be mill rolled, polished, brushed, or pressed to create patterned finishes. Chemical processes may also be used to add a range of colors. Architects take these options into account when creating long-lasting stainless steel for outdoor applications. Ultimately, steel is one of the most versatile building materials, as it may be used both for structural support and for external protection and beauty.

Steel may also be poured into molds to create any shape required.

5. Processing is Required to Prepare Scrap Metal for Recycling.
Before any of these steel-making processes can occur, scrap metal must be processed. Radioactive materials must be removed, ferrous metals must be separated using magnetic drums, and non-metallic materials must be taken out of the mix.

Humans have been manufacturing steel for thousands of years. Without this strong, versatile material, modern skyscrapers would be impossible. As recycled steel and virgin steel are equally strong, salvaged steel is in high demand for new building projects. By recycling this material, we can not only reduce demolition waste, but also help minimize natural resources required for producing virgin steel. Elder Demolition is one of the largest recyclers of scrap steel on the West Coast. Contact us today to learn more about how our steel recycling program could cut your demolition budget.

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