HSLA Steel | Fundamentals of High Strength Steel
Monalisa Patel is a Structural Engineer who has earned her Master’s degree (ME) from the L.J College of Engineering and Technology Ahmadabad in 2018. She is an Engineer (Civil) at SDCPL – Gharpedia. Helping people to solve their queries about construction is her passion. Apart from being blogger, she also participates in structural design at SDCPL. She is reachable on LinkedIn, Twitter, Instagram & Facebook.
Steel is basically everywhere. We are surrounded by steel, without even realizing it. When you are not into, let’s say, construction business, you rarely think about the types of steel that is used for this or that. But when you are involved with structural construction, it’s a must to know the types of steel and their advantages.
With the development of new production and welding techniques such as thermo mechanical control process (TMCP) and micro-alloying technology, the high strength steels with higher strength than conventional low carbon mild steels are being manufactured with required weldability and ductility. In recent years, high strength steel which has higher elasticity is used to build the residential houses as well as high rise buildings. The economy with high strength steel structure is obtained by designing it with advanced earthquake-resistant design concepts.
To Know more, read the characteristics of steel structure and advantage of using steel for building.
So first let us know in brief about types of steel.
Types of Steel
Steel can be broadly categorized into four groups based on their chemical compositions
01. Carbon Steel
Carbon steel has traceable amount of carbon as an alloying element. Carbon steel can be further classified into three different groups depending upon their carbon content.
- Low carbon Steels/mild Steels (0.3% Carbon)
- Medium Carbon steels (0.3 to 0.6% Carbon)
- High carbon Steels (more than 0.6% Carbon)
02. Alloy Steel
Alloying elements like manganese, silicon, nickel, titanium, etc. are added into the steel at the time of manufacturing of alloy steel to manipulate its properties. Steel changes its properties like strength, weldability, hardness, corrosion resistance, etc. due to the varying proportion of alloying elements. Alloy steel is majorly used for pipelines, auto parts, electrical generators, transformers, motor, etc. They are also used in various frame construction.
03. Stainless Steel
Stainless steel contains 10 to 20% chromium which is an alloy element and it allows steel to achieve property like high corrosion resistance. Stainless steel can be further classified into three groups based on their crystalline structure.
Austenitic steel (Generally used in food processing equipment, kitchen utensil, piping, etc.)
Ferritic steel: (Generally used in containers, buses, dhishwashers, cooking utensils, etc.)
Martensitic: (Generally used in knives, cutting tools, surgical equipment, etc.)
04. Tool Steel
To increase the heat resistance and durability, tungsten, molybdenum, cobalt and vanadium are added in the tool steel. Tool steel is ideal for cutting and drilling equipment.
Among all the types of steel, high strength steel is probably the most multipurpose alloy steel. So, let’s figure out what is high strength steel, its difference with its carbon counterpart, and its advantages.
What Is High Strength Steel?
High strength steel is produced by adding small amount of microalloying elements, thus it is also well-known as high strength low alloy steel and also referred as HSLA Steel. High strength low alloy steel has low carbon and alloy content which offer good strength and weldability to it. High strength low-alloy steel is a type of steel that have greater resistance to corrosion, and thus has better mechanical properties. This type of steel widely differs from other types of steel.
High strength steel is produced not to meet a specific chemical composition, but rather to meet certain mechanical and chemical properties. While like most of the types of steel, high strength steel is an alloy of iron and carbon. The content of the carbon is limited, ranging mainly between 0.05% and 0.25%. The reduced content of carbon provides high strength steel with formability and weldability. High strength low-alloy steel contains around 2.0% of manganese, and small quantities of alloying elements like nickel, nitrogen, zirconium, etc. Another important additional alloying elements include copper, niobium, titanium, and vanadium, which are added in order to boost the strength of HSLA Steel.
Advantages of High Strength Steel
In construction, high strength steel is widely used for structural purpose. In constructions, using the high strength low-alloy type of steel has certain advantages. First of all, high strength steel provides the significant reduction of mechanical constructions’ masses. The reduction of constructions’ masses increases the energy efficiency of those constructions. Secondly, using high strength steels allows more flexibility in design. Thirdly, the prices of high strength low-alloy steel remain reasonable, when prices for structural steel tend to increase. The affordable prices make high strength steel more attractive to the manufacturers.
High strength steel is used to manufacture vehicles bodies, agricultural machineries, forestry machineries and also used in construction business. The construction machineries like concrete pump, concrete mixer, mobile cranes, utility vehicle, etc. are made up of high strength steel. As per the modern demands, conventional steel is mostly replaced by the high strength steel. From past few years, many high-rise buildings are being constructed with the high strength steel. The high strength, high resistant to corrosion, and high elasticity of high strength steel made possible to reduces the thickness of member under the difficult load conditions. The use of high strength steel provides high level of flexibility in design of mechanical construction. High strength steel improves the safety of the structure and reduce the maintenance cost of the structure. Finally, there is an ecological advantage of high strength steel, as it has lesser negative impact on the environment while being used for mechanical constructions.
After learning all these, one can say that apart from use in heavy industries, high strength low-alloy steel is also a highly demanded construction material. This type of material is slowly replacing the conventional steels as it has superior mechanical properties, good weldability and it is highly resistance to corrosion. It is economical as compare to the conventional steel. It has ecological advantage too. High strength steel has higher lifting and load carrying capacity as compared to the conventional steel. During the manufacturing of high strength, it consumes less power reducing the production cost. It is also low in weight as compared to the conventional steel. High strength steel requires less filler materials and good cutability during the work makes it superior on the construction site.