Stainless steel materials have numerous variations and are widely used in projects and applications. All types of stainless steel include various properties such as corrosion resistance, oxidation resistance, tensile strength, melting point, etc.
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Sree Metaliks Ltd. (SML) is one of the leading steel manufacturers known for producing high-quality TMT bars for over two decades. The company has established a state-of-the-art manufacturing unit with a top-notch quality control facility in Odisha State.
Here is a comprehensive guide prepared by Sree Metaliks to help you understand the usual stainless steel types and grades.
What is Stainless Steel?
Stainless steel is a metallic alloy manufactured using a combination of different base metals, eventually forming a new product that is more robust and durable. Sree Metalliks' stainless steel products are green, making them conveniently recyclable. These steel materials provide longevity and are environmentally friendly, catering to sustainable construction commitments.
Different Ingredients Needed for Stainless Steel Production
We at Sree Metaliks use an extensive range of alloys for stainless steel manufacturing to deliver different outputs. These ingredients are:
- Nickel: Nickel is the main component of stainless steel manufacturing. It is an assured alloy that improves the steel’s weldability, ductility, and formability. It is also corrosion-resistant.
- Carbon: Stainless steel materials with the highest carbon content have the most phenomenal longevity and durability compared to other alloys. These steels are the raw materials for cooking appliances and food-grade utensils.
- Chromium: Chromium in stainless steel products has different features, such as perfect resistance to stains, corrosion, and tarnishing. It also has comprehensive applications in outdoor installations.
Types of Stainless Steel
There are five major types of stainless steel in the domestic market. These are as follows:
1. Austenitic
The most popular stainless steel grades are 304 and 316. These stainless steel types and grades comprise 16 to 26% chromium and 35% nickel content. The austenitic steel category has the maximum corrosion resistance capacity and does not harden despite heat treatment. This stainless steel family is robust, malleable, and nonmagnetic.
Types of stainless steel 304 have the most widespread application. This austenitic variety is also called 18/8, comprising 18% chromium and 8% nickel, and is commonly used in aerospace and food processing units. The physical properties of austenitic stainless steel are similar to ferritic or martensitic steel. However, the chemical composition varies completely.
2. Ferritic
Ferritic stainless steel has a low carbon content (less than 0.2%), allowing it to remain soft during heat treatment. However, this type of steel can be moderately hardened by cooling treatment. Accordingly, it has lower anti-corrosion elements than austenitic steels. Conventional ferritic stainless steels contain 10.5 to 27% chromium alloy and are entirely devoid of nickel. The different grades of stainless steel of a ferritic nature include 409, 430, 439, and 441. This variety has a standard application in architecture and auto trim.
3. Martensitic
The different types of stainless steel also include martensitic steels, which contain 11.5 to 18% chromium and 1.2% carbon content, and nickel. These steel types are hardenable by heat treatment. They are magnetic and have moderate corrosion resistance. They frequently come with 400-level grades. Besides, these steels are popular as raw materials for wrenches, cutlery, surgical instruments, and turbines.
4. Duplex or Austenitic-Ferritic
Duplex steels have equal proportions of austenitic and ferritic components. This steel comprises 21 to 27% chromium, 1.35 to 8% nickel, 0.05 to 3% copper, and 0.05 to 5% molybdenum. The ideal combination of elements makes this stainless steel category more robust and durable than austenitic or ferritic steel. Duplex steels have typical applications in chemical processing plants and the manufacture of chemical storage containers.
5. Precipitation-Hardening Stainless Steel
Stainless steel types and grades also include precipitation-hardening steel, which has remarkable strength. It contains 15 to 17.5% chromium and 3 to 5% nickel. It also has a moderate shade of other alloys, such as copper, aluminium, and niobium. These three alloys have less than 0.5% existence of the total mass of the subject steel. The corrosion resistance of precipitation-hardening steel is similar to that of austenitic steel. You can harden this steel type with an ageing treatment at a relatively low temperature. Metallurgical units nationwide use this steel category for making long shafts for valve spindles and pumps.
Stainless Steel Grades: A Brief Explanation
As you have observed, there are five different types of stainless steel. You may term these classifications families, which are further subdivided into grades. Then, you should know the distinction between a family and a grade of stainless steel. The stainless steel family is the ratio of the metals that create the alloy. Conversely, steel grades reveal the properties of the steel family, like strength, corrosion resistance, magnetism, etc.
Several reputable steel manufacturing companies, like Sree Metaliks, have researched and developed captive units for grading stainless steel. When our metallurgists and rolling mill technicians mention 304 and 316, they indicate the AISI model of stainless steel grades.
Determination of Perfect Stainless Steel Material for Industrial Use
Selecting the type of stainless steel as raw materials for your upcoming construction project may be difficult. We at Sree Metaliks have tried to make it easier for you to choose the correct category. It will help if you take note of the following factors before making a final decision:
- Environment: The working environment at the construction site or factory shop floor might influence the application of stainless steel as an input. The onus lies in choosing a steel grade with strength, durability, and resilience to defy temperatures, stressors, pH, and corrosion that may hinder your work progress. For instance, a marine environment may go well with an alloy comprising molybdenum that mitigates chloride ions.
- Weldability or Formability: If the job requirement is foolproof formability, stakeholders' preference for construction work should be austenitic or ferric stainless steel 304 or 430, respectively. If you use martensitic steel like grade 410, your building may collapse during construction. Further, you should consider the weldability element if your project layout demands welding stainless steel sections with another metal.
- The Pertinent Element of Corrosion Resistance: An adequate level of chromium alloy in types of austenitic stainless steel is a decent alternative when the construction site experiences consistent harsh weather. The austenitic steel family's grade 316 offers the optimum corrosion resistance. If you are low on budget, we recommend using martensitic or ferritic stainless steel materials, which are cost-effective and most helpful in corrosive settings.
- Strength, Durability and Ductility: What should be the weightage of your application? How will it operate without loss of strength? Different grades of stainless steels comprising chromium and nickel provide the most trustworthy combination of strength, ductility, and resilience.
- Availability and Cost of Procurement: We have found that austenitic stainless steel is generally the most expensive preference. With this in mind, the experts always recommend these types of stainless steel because buyers and construction supervisors may be delighted that they have saved money on repairs and maintenance of the structures in the long run.
- The Essence of Magnetic Response: A few popular types of stainless steel tend to have a higher propensity for magnetism than others. The addition of chromium in a separate alloy makes it more magnetic. However, mixing nickel with the stainless steel material may eliminate the prevalence of alloy. Different grades of stainless steel, like 316 and 310, are invariably nonmagnetic, while stainless steel types and grades in the 400 series are highly magnetic.
Eventually, you will have to select the best among equals! It depends on the nature of your work, your job preferences, and environmental factors. An experienced entity in the domestic market, Sree Metaliks always strives to produce the most suitable stainless steel products for various construction works in our country.
Conclusion
These facts substantiate that stainless steel has revolutionised the Indian construction domain, whether large or small, by facilitating the essential elements that make the indigenous market a force to reckon with. Sree Metaliks is making a notable contribution to this industry by manufacturing quality stainless steel products. Our manufacturing process, regular shop floor maintenance and revamping, and adherence to prescribed standards have paved the way for reinforced concrete structures' structural integrity and safety.