A lot has been said about the versatile properties of steel that make it the perfect fit for various industrial applications. Steel’s chemical properties have a lot to do with steel being a widely used metal. Using different grades of steel, steel producers create various types of steel products. The selection of the right grade of steel used can do wonders, that is why knowing how to select the right steel grade is vital in the steel production process.
Be it any grade, steel can be recycled but steel scrap prices vary from one variant to the other. Mild steel scrap price will be different as compared to any other grade. With that being said, if you don’t know much about how to opt for the right grade and you still get confused, worry not. We have got you covered.
We present a guide for you that makes you crystal clear about different grades so that you can confidently know which steel grade is used for which product.
Understanding The Meaning
The steel grade is defined as steel’s composition and quality. Steel is an alloy of carbon and iron, loaded with other elements such as silicon, manganese etc. There can be times when traces of chromium, vanadium, and nickel can be found in the steel. The composition of different elements in steel and the processing methods used can have a significant impact on various properties of the steel, such as hardness, ductility, strength, and corrosion resistance.Typically, represented by an alphanumeric/ number code, steel grades indicate the composition as well as steel properties. For instance, the most used steel grade is 304. Since it is an austenitic stainless steel type, it contains 8% nickel and 18% chromium. It is well-known for its corrosion resistance and high-temperature strength.
Types Of Steel Grades
As steel has different types, different steel types have different grades. Consider steel as a category, steel type is a sub-category, and steel grade is another category of the sub-category.
Let’s explore different types of steel along with their most popular steel grades available in the market:
1. Mild Steel: It’s relatively less costly as compared to other steel types. The same is reflected in mild steel prices per kg. Apart from prices, its other key characteristics are its excellent strength and ease of fabrication. These amazing features make mild steel a preferred choice for various be it railway tracks, bridges, fencing etc.
The commonly used mild steel grades are listed below:
· A36: It comes with pretty good mechanical properties, including but not limited to a high STW (strength-to-weight) ratio.
Apart from A36, JIS G3101, S275JR, SS400, and AISI 1018 are the most used mild steel grades as well. Keep in mind that mild steel scrap price will vary from one variant to another.
2. Carbon Steel: Generally ranging from.05%-2.0%, this steel type of steel has carbon as the primary alloying element.
Here are some of the variants of carbon steel grade:
· ASTM A36: It is used in structural applications like bridges, building frames, & machinery parts as it provides good strength & formability. Apart from this grade, grade AISI 1045 is preferred for applications requiring medium carbon steel and AISI 1018 and ASTM A572 is used for applications requiring low carbon steel.
3. Alloy Steel: Apart from carbon, this steel type contains other elements in varying proportions so that its basic properties can be altered.
Here are some of the variants of alloy steel grade:
· AISI 4130: Containing molybdenum and chromium, it is a low-alloy steel grade. It offers toughness and strength, which is why it is suitable for use in structural tubing, and aircraft components.
Additionally, AISI 4140, ASTM A387 Grade 11 and AISI 4340 are used for applications like shafts, boilers and gears.
4. Stainless steel: It is one-of-a-kind steel that at least has 10.5% chromium, which loads stainless steel with corrosion-resisting properties. The commonly used grades of stainless steel are:
· AISI 304: It comprises 8% nickel and 18% chromium, no wonder it is also referred to as 18/8 SS. Generally, it is used for food processing, kitchen equipment, and architectural applications.
In addition to that, grades AISI 430, AISI 410 and AISI 316 are used for making kitchen appliances, medical devices, and marine equipment.
Points To Keep In Mind
When it comes to choosing the right steel grade, be mindful of the following:
1. Heat Compatibility: Some steel grades are compatible with heat treatment. To upgrade the hardness, strength, or other properties, they can be treated with heat if need be. If the desired application exposes steel to heat treatment, it’s a pre-requisite to opt for a grade that offers heat treatment compatibility. Steel grades like 4340 and 4140 are the perfect fit for such applications.
2. Strength: By default, it is important to keep steel’s strength in mind when it comes to zeroing down a steel grade. Typically, steel’s strength is measured by its yield strength. Simply put, the amount of stress it can be exposed to before it starts deforming determines steel’s strength. If the yield strength is on the higher side, its strength is on the higher side as well.
Be aware of the strength level needed for your usage first and then select a steel grade. In case you want to build a bridge, it is bound to be subjected to heavy load. In that scenario, you need a high-strength grade such as ASTM A992 or ASTM A709.
3. Machinability: It offers the ease with enables a grade to be either machined or cut into a specific shape. There are a few steel grades which are relatively higher machinable as compared to the other steel grades. The extent of machinability needed for a specific application depends totally on the complexity of the shapes that need to be created. Grades such as 1215 and 12L14 etc. are the most preferred choices for high-machinability oriented applications.
- Weldability: The ability to weld steel gives it an extra edge for various applications as some steel grades offer better weldability. Keep in mind that the welding type can also impact the steel’s weldability. For welding-oriented applications, grades like A572 or A36 are your safest options.
5. Non-Corrosion: When it comes to steel usage, corrosion can offer major setbacks for many applications. Exposure to harsh environments such as acidic chemicals or saltwater can make steel rusty in no time.
Stainless steel grades such as 304L or 316L are ideal choices for corrosion-oriented applications, all thanks to their non-corrosion properties that keep corrosion and rust at bay.
6. Formability: Steel grades can form a specified shape keeping its shape intact without breaking or cracking. Specific steel grades offer better formable features than the others. The extent of formability needed for an application entirely depends on the complexity of the desired shape that needs to be created.
Grades such as A606 or A1011 are preferred choices for applications needing a high level of formability.
But we have just scratched the surface
The points covered in the article can be your guiding light when it comes to opting for the best steel grade based on different applications. While being familiar with the factors will be helpful, that is not all. When selecting the best steel grade evaluation, a wide range of factors come into play such as the kind of steel to use, the product’s end-use, tensile strength, the operating environment’s type etc.