What Are Advanced High-Strength Steels?
In many of the world’s languages, there’s a common expression “as strong as iron.” Metals and iron are the first of them and have for centuries been synonymous with hardness and inflexibility. This stable image is quite understandable to us, although it would have been more accurate to say “as hard as steel”— a tough, wear-resistant alloy that copes well with the processing of other metals and abrasive rocks.
How Is Advanced High-Strength Steel Made?
High strength steel is steel with a tensile strength of at least 1800÷2000 MPa. Trustworthy companies, like Metinvest holding, include the following alloying elements in high-strength steels: chromium, nickel, and molybdenum. These elements significantly increase resistance to brittle fracture. In addition, high-strength steels contain silicon. Silicon considerably delays martensite decomposition and carbide coagulation at low tempering.
Silicon alloying makes it possible to obtain high-strength steels by applying higher temperatures and reducing internal stresses. Silicon-containing steels have slightly higher strength at the same temperature, which reduces the carbon content of the steel; that, in turn, improves weldability and increases resistance to brittle fracture. Silicon delays the breakdown of martensite under the influence of plastic deformation. As a result, silicon significantly enhances the mechanical properties of high-strength steels subjected to hardening and low tempering.
Types of High Strength Steels
Essential characteristics of high-strength steels, in addition to high tensile strength and yield strength, are crack resistance and retention at an acceptable ductility level. Weldability is also an important consideration.
The high-strength steels are of the following types:
- Medium-alloyed low-temperature steels
- Martensitic steels
- TRIP steels
Advantages of High Strength Steels
When it comes to loading, shredding, compacting, and further processing scrap metal, wear and tear on the production equipment is an inevitable part of every stage of the process. Grapples, hydraulic shears, shredders—all these mechanisms, combining directly with the recycled material, need quality wear parts in the first place.
Wear-resistant steels have a well-balanced chemical composition and, as a result, are resistant to cracks and dents. Advanced high-strength steels protect equipment and increase its productivity as a whole. Modern machine tools allow the processing of steel at all stages of the production process: cutting, bending, machining, and welding. In this case, it’s possible to repair and restore ready assemblies and equipment and order new ones according to drawings.
Proper selection of steel grades, machining with well-established technological production schemes will ensure that the steel will withstand the heaviest loads and last even in the most adverse conditions.
Prospects for High-Strength Steels
Specialists link the possibilities of further increasing the strength of steels primarily with nanocrystalline materials and materials with highly dispersed nanoscale separations. It has long been known that a reduction in grain size leads to an increase in the strength of metals, but there’s also a decrease in flexibility. However, recent studies have shown that forming a nanocrystalline structure in some metals can significantly increase strength while maintaining high ductility.
