12 oktober 2020
Stainless steel has long been crucial for many applications where strength, durability, and resistance to corrosion are essential. That is why it is often chosen for process equipment used in harsh environments such as chemical and petrochemical plants, refineries, and power stations. Unluckily, from a metalworking perspective, the same qualities that make it perfect for heavy industries also mean that it can be a challenge to work with. Here we look at three issues stainless steel presents to material removal applications and share tips on how to overcome them.
Compared to steel and other iron-based materials, stainless steel has a significantly lower heat conductivity. This means that it gets hotter locally when worked on, making many material-removal tasks, such as weld seam removal, difficult.
The most effective way to minimize the risk of overheating is to select a low-speed tool. Tools running at less than 4000 rpm are a good choice, as the relatively low speed will not allow the material to heat up, enabling the work to continue undisturbed as long as needed. It is also important to pay attention to how the tool is handled and avoid pushing it against the metal too hard, as it can contribute to overheating and, in the worst case, melt the metal onto the abrasive.
The parts being worked on are often very thin, and the material removal tasks run a high risk of damaging the product. To avoid this, the work needs to be carried out extremely carefully, which is time-consuming, and some tasks, like grinding, can slow down the entire production flow.
First of all, it is crucial to accept that with stainless steel, some tasks will take longer and take this into account when planning the work schedule. Selecting the right abrasive can also help speed up the process and contribute towards the best possible finish.
As stainless steel can be a demanding material to work with, achieving a good quality finish for painting is often a challenge, especially in an operating environment where other materials are being worked on simultaneously.
There are no shortcuts to a quality finish, and that is why it is essential to use the correct tools and inserts and eliminate any risk of damage from cross-contamination. The abrasive must be changed between using it on carbon steel and stainless steel, or the remains of the carbon steel will ultimately damage the stainless steel product. It is also useful to compare the options available and select the best possible insert for each task, as their features – and results – differ. For example, flap discs with finer grit can deliver a better finish in softer operations but make the process inefficient in other applications.
Aluminum’s thermal connectivity is around four and half times higher than stainless steel, and it is also cheaper. However, stainless steel tends to be the favored material for heat exchangers, because it is strong, durable, corrosion-resistant, and, ultimately, better value in the long run.