Stainless steel is used in a wide range of applications due to its versatility. The fact that stainless steel is highly resistant to tensile stress, corrosion, and rust makes it an important part of rapid prototyping. To work with stainless steel, it is important to understand all of its properties. Therefore, there is a need for a stainless steel material selection guide that describes the different types of stainless steel, their grades, qualities and uses.
To make things easier, this article will help you choose the right stainless steel material. It details the different grades of stainless steel, how stainless steel works, and the different types of stainless steel you can use for your project. It will also give you an idea of how to choose the right grade of stainless steel for quick prototyping.
Table of Contents
What Is Stainless Steel?
Properties of Stainless Steel Materials
The metal elements that make up stainless steel play an important role in its chemical and mechanical properties. Because of this, it is an important material in rapid prototyping manufacturing methods such as CNC machining and sheet metal fabrication. The qualities of stainless steel depend on the grade of stainless steel you want to use. However, the following are some general properties of stainless steel that apply to all grades of steel you may use.
Corrosion Resistance
Stainless steel contains chromium, which makes it highly resistant to corrosion. This is one of the most important properties of steel, and it makes stainless steel useful in many rapid prototyping processes such as CNC machining. Stainless steel can also withstand harsh chemical and atmospheric conditions due to the way the elements are mixed.
High Tensile Strength
Another important feature of stainless steel is its high tensile strength. Because of this, stainless steel is an excellent material for making items that can withstand pressure and weight.
Strength and Toughness
Stainless steel can withstand friction and impact even in harsh environments. Stainless steel can also withstand energy and will not crack or break when subjected to pressure.
Ductility
Stainless steel is highly ductile and therefore can withstand the stresses of the manufacturing process without deformation. In addition, stainless steel metal is hard and loses heat quickly. It is therefore difficult to cut or shape without the right tools. If rework is required, it can lead to damage and waste of parts.
Advantages of Stainless Steel
Stainless steel is used in many applications because of its many useful properties. Some of the reasons why stainless steel is used in different industries are listed below.
- Corrosion Resistance. Since stainless steel is an alloy, chromium makes it rust-resistant. Therefore, stainless steel can be used to make items that are resistant to chlorine, alkalis, and acidic environments without rusting. Different grades of stainless steel such as 416, 316, 440, 2205, etc. have excellent corrosion resistance.
- Tensile Strength. Stainless steels such as Grade 416 and Grade 431 have higher tensile strength than other metals. This is because it can withstand greater weight and stress even at very high or low temperatures.
- Ease of Maintenance. Stainless steel is easy to maintain after it is made, so its long-term value is higher than its initial cost.
- Heat Resistant. Stainless steel grades such as 2205 and 416 are resistant to scaling caused by high temperatures. Therefore, it is more suitable for making items that are exposed to extreme temperatures.
Disadvantages of Stainless Steel
However, there are some problems with stainless steel, even though its properties make it useful in many situations. Here are some of the disadvantages of using stainless steel in your next job.
- Expensive. Stainless steel contains additional alloying elements such as nickel and chromium. This makes it more expensive than other types of steel. These elements are the key to stainless steel’s resistance to rust. Because of the way stainless steel is processed, its surface treatment and polishing are also costly.
- Easy to Get Dirty. Stainless steel products get dirty easily, which reduces their attractiveness.
- Difficult to Fabricate. Fabrication can be very difficult depending on the type of stainless steel used. Therefore, you need to know about the different grades of stainless steel before choosing the right one.
Different Types of Stainless Steel
Before selecting the grade of stainless steel for your project, you need to understand the different types of stainless steel. Each type of stainless steel has different properties. Therefore, they are good choices in some cases. Below are the main types of stainless steel and the grades to which they belong.
Ferritic Stainless Steel
Ferritic stainless steels are commonly used in construction projects because they are stronger than other types of steel. They have the same body-centered cubic crystal structure (BCC) as pure iron or carbon steel and contain more iron and chromium, as well as small amounts of other metals.
Because of their structure, ferritic stainless steel cannot be hardened by heating. Ferritic stainless steel is also less expensive. When appearance is not important, ferritic stainless steel is a good choice.
In the different types of ferritic steel, you can find metal elements such as nickel, manganese, silicon, phosphorus, sulfur, and titanium. Below is a list of common stainless steel grades made from ferritic steels:
- Grade 409. This stainless steel does not rust at extreme temperatures and has good mechanical properties. It is mainly used in automobile exhaust pipes and in buildings exposed to high temperatures, etc.
- Grade 416. This type of ferritic steel is best suited for machining. It is therefore used in the manufacture of threaded machined parts, nuts, pump and motor shafts, valves, and gears.
- Grade 430. Grade 430 ferritic stainless steel is less prone to rust. It is also heat and oxidation-resistant. Therefore, this grade of stainless steel is commonly used in the manufacture of food industry and household products.
Austenitic Stainless Steels
One of the best-known steel grades in the market is austenitic stainless steel, such as 316 stainless steel. They have a face-centered cubic (FCC) crystal structure and contain high amounts of nickel and chromium. As a result, they have excellent corrosion resistance and are non-magnetic, especially after annealing.
Due to the high amount of nickel and the fact that they become stronger after cold working, austenitic stainless steels work well at low temperatures. In addition, austenitic stainless steel can be used in the food and production industries. The following are three commonly used austenitic stainless steels and their uses.
- Grade 316. Grade 316 is available in two types: 316 and 316 L. Both types are easy to work with. As such, they can be used in the food industry and power generation industry to manufacture products through rapid prototyping techniques.
- Grade 304. You are likely to come across this type of stainless steel. Its non-ferrous materials are nickel and chromium. Because of this, it is used to make items that can be used in saltwater environments. It is used to make items such as fasteners, pipes, and freezers used in the food industry.
- Grade 310. This stainless steel can be very resistant to high temperatures. They are used as cryogenic materials in combustion tanks because they are very resistant to heat and scaling. Based on this feature, they have other uses.
We have provided a 4140 vs 4130 Steel comparison, please check out the!
Martensitic Stainless Steels
Martensitic stainless steels contain high amounts of carbon (0.1% to 0.12%) and chromium (10.5% to 18%) and are magnetic. Because of their high carbon content, these stainless steels require heating and cooling to harden.
As a result, they can be used in applications where the strength, resistance, and machinability of stainless steel are required. There are many types of martensitic stainless steel. The following are some of the most commonly used in rapid prototyping.
- Grade 431. Of the martensitic stainless steels we discuss here, Grade 431 is the least susceptible to rust. After heat treatment such as tempering, it becomes hard and very resistant to corrosion. For this reason, it is often used to make parts for use in freshwater.
- Grade 440. Grade 440 steel is available in three variants: 440a, 440b, and 440c. They are made from hard, high-carbon steel that has been heat-treated to make it strong and wear-resistant. In addition, they are not harmed by acids, alkalis, or water. Therefore, they can be used in scenarios involving such conditions.
- Grade 416. If you want to machine stainless steel, grade 416 is one of the best types (about 85% machinability). It is, therefore, an important material for the manufacture of motor shafts, screws, nuts, bolts, gears and valves.
Duplex Stainless Steel
Duplex stainless steel is a new type of stainless steel consisting mainly of equal amounts of ferrite and austenite elements. This mixture has very high strength and corrosion resistance, especially to chloride corrosion.
They are also resistant to stress because they contain high levels of chromium and molybdenum and low levels of nickel. This makes them twice as strong as other types of steel. Duplex steels are cost-effective and are commonly used in offshore, building, and construction applications. Duplex steels are available in two different grades, which are:
- Grade 2304. People like 2304-grade stainless steel because it does not rust and is very strong. They are better than grade 316 stainless steel because they do not contain molybdenum. They are a popular material for making items for the food and beverage industry.
- Grade 2205. Grade 2205 stainless steel has the properties of both ferritic and austenitic stainless steel. It is highly resistant to rust due to its high content of molybdenum and chromium.
Precipitation Hardened Stainless Steel
Stainless steels that are hardened by precipitation are austenitic or martensitic stainless steels. It can also be heat-treated to make it easy to work, magnetize, and become very strong. Grades of stainless steel can be differentiated based on nickel and chromium content. The following are a few common grades of stainless steel that are hardened by precipitation.
- 17-4PH (17% chromium, 4% nickel). This stainless steel contains 17% chromium and 4% nickel. Because of its high corrosion resistance, it can be used in many food-related applications. It is also used for larger CNC machining applications, such as the manufacture of aircraft engine blades or other mechanical parts.
- 15-5 PH (15% chromium, 5% nickel). 15% chromium and 5% nickel make up this type of stainless steel, which has the same stainless steel properties as these two materials. It can be used to make many things such as airplane parts, valves, gears, shafts, oil well parts, and nuclear reactor parts.
How to Pick the Right Grade of Stainless Steel
There are different types of stainless steel. Because of this, it has a variety of starter options. Nonetheless, it can be difficult to pick the correct grade of stainless steel for your project. Therefore, this section will serve as a guide to selecting stainless steel materials, outlining the different factors that will help you decide which grade of stainless steel to use.
Consider the Welding Process
Austenitic stainless steels are suitable for any process that needs to be made from stainless steel that can be welded well. This is because they don’t have much carbon.
You can also weld ferritic stainless steels such as 409 and 430. Martensitic steel, on the other hand, is not suitable for welding because it is weak, breaks easily, and cracks frequently.
Consider Formability
Austenitic steels such as 316 and 304 and ferritic steels such as 430 and 409 are good choices for processes that require stainless steels that are easy to form. Martensitic stainless steels are less brittle and difficult to form.
Corrosion Resistance
Among the different types of stainless steel, austenitic stainless steel is highly resistant to corrosion. This is because it contains high amounts of chromium and molybdenum. It can be used outdoors as stainless steel is not affected by weather and other factors. Ferritic and martensitic are cheaper than austenitic as far as corrosion resistance is concerned.
Heat Treatability
Heat treatment is an important consideration when looking for the right grade of stainless steel for a project.17-4 PH, martensite can be heat treated. However, austenitic and ferritic steels cannot withstand the high temperatures associated with heat treatment.
Mechanical Properties
The mechanical properties of stainless steel are of course very important when selecting the right steel. You should consider factors such as temperature, strength, toughness, ductility, and extensibility before making your choice.
Cost-effectiveness and Availability
Quality is very important when choosing the right grade. You can choose a grade that is easy to find, less prone to corrosion, less expensive, and of good quality. Austenitic steel is a good choice as far as quality is concerned, but it is harder to find because it is more expensive than other types of steel.
Common Uses and Applications of Stainless Steel
Many different types of industries use stainless steel in different ways. Here are some of the ways stainless steel is used in rapid prototyping products.
Food Industry
Kitchenware such as sinks, cutlery, plates, and platters are made from stainless steel. It can be used in this area because it does not rust or corrode and does not allow microorganisms to grow on it.
Medical Field
The medical field is an important area where stainless steel is used. In this case, stainless steel can be used to make surgical tools. For example, it can be used in surgical implants for fixing broken bones and implanting tools.
Aerospace and Automotive Industries
Parts of airplanes and automobiles are made from stainless steel, an important material. Stainless steel can be used in these areas as long as it is manufactured correctly and accurately.
Other Industries
Stainless steel can also be used in other ways, such as making cookware and lighting products. As you can see, stainless steel is very versatile, which is important for rapid prototyping fabrication such as CNC machining.
Conclusion
Stainless steel materials are very important in manufacturing. Which stainless steel to use depends on many factors, such as the grade and properties of the stainless steel. This article will help you fully understand this by telling you how to choose the right stainless steel material. It talks about the different types of stainless steel, their grades, and their features. It also provides guidance on how to pick the right steel for you.
FAQ
Why Does Stainless Steel Not Rust?
The rust-resistant properties of stainless steel come from the properties of the constituent metals. Due to the presence of elements such as chromium, stainless steel has excellent corrosion resistance.
Which Stainless Steel Is Best?
Depending on your needs and location, Grade 316 stainless steel is highly resistant to corrosion and is the best choice for exposure to chlorine, chemicals, and the environment.
How Long Does Stainless Steel Last?
The service life of stainless steel is relative, as it depends on how and where it is used and the elements that make it up. Normally, the service life of stainless steel ranges from 20 years to over 1,000 years.