Production Process of Stainless Steel Flange
Flanges are a basic necessity in the piping industry. They are plates with holes in their corners. They allow us to connect two pipes firmly without causing any leakage. Stainless steel is a popular material used in making these flanges. However, many people seem to be consulted regarding the production process of stainless steel flanges.
In this article, I will discuss all the steps involved in flange manufacturing. If you’re new to piping or the plumbing field, this article is for you. It will explain everything regarding stainless flanges in the most straightforward words. So, let’s get started!
Why Stainless Steel Flanges are Popular?
Let’s first learn why stainless steel flanges are so popular.
Stainless steel flanges are rust-resistant, durable, and robust. They can easily bear high fluid pressure without showing signs of leakage. Moreover, they are easily available and relatively cheaper. All these factors make stainless steel flanges very trendy in the piping industry.
Remember, this material is an iron-based alloy containing various alloy elements. It also includes 10.5% of chromium, which makes stainless steel very special. This chromium makes a chromium oxide layer when it comes in contact with oxygen. This oxide layer is very robust and prevents rusting of this material.
Therefore, flanges made with stainless material are rust-resistant. That’s why people prefer using stainless flanges. It does not mean that stainless flags are 100% rustproof. However, their performance in moist conditions is better than other materials i.e. carbon steel or aluminum. Another reason behind its popularity is its excellent pressure-bearing capacity.
The flanges generally connect two pipes carrying high-pressure fluid. So, they must be strong to bear the pressure. If they are weak, you’ll see leakage issues on the flanges. However, stainless material bears pressure efficiency. As a result, flanges made of these materials remain secure no matter how high-pressure fluid pipes carry.
Step by Step Production Process of Stainless Steel Flanges
The production of these flanges is not easy. Therefore, I’ve divided this portion into easy-to-understand steps. This will help you better understand how stainless flange production takes place. So, let’s get rolling!
1- Select Right Stainless Steel Type
Stainless steel comes in many types and grades, each varying in terms of properties and price. For example, grade 304 stainless steel offers exceptional corrosion resistance. Conversely, 316 stainless steel provides excellent performance when you need chemical resistance. You should analyze the conditions where your flange will be used before making a final decision. This will help you choose the correct type of stainless steel.
2- Cutting of Stainless Steel to make Raw Flange
The second step is to cut the material that you selected. As you know, flanges are circular with holes on the sides. Right? So, you should also cut the material to get a circular plate. Remember, some manufacturers also offer sheets and plates of stainless steel. You can use that pre-made plate to reduce the hassle.
Different techniques and machines are available for cutting the sheet. Some standard methods include:
- Laser cutting
- Plasma cutting
- Waterjet cutting
Generally, plasma cutters are preferred if you select very thick stainless steel. However, laser and waterjet cutting provide precision. Remember, modern cutting machines also come with CNC features. This means that they are controlled by computer systems, which enhances their precision. This step will give you a raw circular-shaped flange that requires more machining.
3- Heating, Forging and Shaping of Raw Flange
Once the raw flange is cut, it undergoes heating at 950°C to 1250°C. This heating plays a key role in shaping the raw flange. The heating makes the flange malleable and easy to shape. After heating, the softened or malleable stainless steel flanges fit into the mold, which is similar to the desired shape of the flange.
Once the mold is closed, it undergoes pressing. As a result, the malleable material adopts the shape of the mold. So, you get the flange that is precisely similar to your desired shape. This process of heating and then shaping is called forging. This process has two types: open-die forging and closed-die forging.
Open-die forging is generally used when manufacturing a larger flange. On the other hand, closed-die forging uses a mold and is suitable for producing smaller flanges. Modern manufacturing uses forging machines to shape the flange after heating. These machines are more quick and efficient.
4- Rough Machining for Better Quality
The forging process gives the flange a desired shape. However, there are still some uniformity issues, especially from the edges. Therefore, this flange undergoes further machines. Generally, CNC lathes or milling machines are used to produce excellent finishing. These machines remove the unnecessary edges and unwanted material from the flange. After this machining, the flange edges become uniform and smoother.
5- Drilling Bolt Holes
The machining gives the flange a perfect finish and uniformity. The flanges are ready for holes. Remember, creating holes can be a more tricky step in stainless steel flange production. The holes are generally drilled in a circular orientation near the edges of the flange.
Multiple parameters must be considered when drilling. The holes must be of equal sizes in terms of diameter. Moreover, the spacing between holes and their depth must be uniform. Small mistakes in a drilling hole will result in misalignment when you put nuts in these holes. In the past, drilling holes required maximum human attention.
However, things have changed as CNC drilling machines have taken over. Manufacturers program these machines with instructions. As a result, the machines follow the instructions and drill accurate holes. Their accuracy and speed make them a must-have when manufacturing flanges.
6- Heat Treatment for Better Strength
The stainless steel material is very robust. However, flanges made with this material still need some additional heat treatment. This process of heating ensures better mechanical strength of the flange. The heat treatment is done at a controlled temperature. Moreover, there are two ways to do it, which are as follows:
- Annealing
- Quenching & Tempering
The annealing involves heating and cooling the flange slowly. On the other hand, quenching & tempering are done quickly. In this process, the flange undergoes extreme cooling and is then suddenly exposed to high temperatures. These two processes relieve the internal stress and improve the toughness of the flange.
7- Surface Treatment & Polishing
The heating improves the durability and makes it ready to be used. However, manufacturers put this flange under additional surface treatments. For example, they use turning machines to create smoothness of the surface of the flange. Moreover, boring and chamfering are done to check the inner bore of holes.
Some manufacturers apply a coat of paint to the flange to make it resistant to corrosion. However, this coating is not very important. The reason is that the stainless steel material itself is rust-resistant. After this surface treatment, the flange undergoes inspection. During this process, it is tested under real-world conditions. If it fulfills the set standard, it is approved and becomes available for use.
Conclusion
The production of flanges can be tricky, especially if you don’t have the right tools. In this article, I’ve mentioned the use of various tools and machines. Without them, the process becomes challenging. The chances of human errors affect the quality of the stainless flange.
Generally, flanges are manufactured by professionals. I don’t consider this production a DIY project. In this article, I’ve explained the complete manufacturing in easy-to-understand steps. If you have tools, following those steps will help you make flanges. However, if you don’t have tools, I’d suggest not trying this process.