Today, stainless steel has a wide application – so we have all heard of it. It is steel reinforced with other elements that have special properties, primarily anti-corrosive properties. That is why it is so widespread in the use of modern man. And what is the process of obtaining stainless steel, that is, it’s casting? Here’s what you should know.
Stainless Steel: Properties and Advantages
Stainless steel is a material with quite rewarding properties. Namely, we use it for making various things. We use it almost everywhere, from kitchen utensils and appliances to medical devices – and even jewelry. Its advantage is that in combination with other elements such as chromium, molybdenum, nickel, and others – this material acquires improved anti-corrosive properties.
That makes it ideal for application in many industries. Therefore, it is not surprising that stainless steel is very often used in the construction of large industrial machines, many of which are in contact with water. Namely, this material is known for not keeping any traces of water remaining on it – even though there are cases when it is not entirely water resistant, it all depends on the environment.
Resistance of Material and Scope of Application
Probably the most important of all the advantages of stainless steel is its corrosion resistance. Stainless steel’s resistance to corrosion and stains, easy maintenance, and shine – make it an ideal material for multiple purposes. The alloy is melted into coils, plates, sheets, strips, wires, and pipes.
Today, we are using it in the kitchen, appliances, households, instruments in medicine, large machines, industrial equipment, etc. We also use it as an automotive and aerospace structural alloy and structural material for large buildings. So, we can say it is a multi-purpose and one of the most widely used materials today. Considering the advantages, it is optimal for use even for medical purposes.
Casting Of Stainless Steel: The Procedure
As for the production itself, that is, the stainless steel casting process, it is not one of the cheapest or most affordable procedures. According to dawangcasting.com, the stainless steel casting procedure requires heating the material above its melting point. That also goes for its additional components that will make this alloy the way it should be – solid and stainless. The materials must be introduced into special molds and cut into the desired shape. To better explain this procedure, we need to go step by step. So, here’s what it looks like.
● Preparing the mold
Casting molds for stainless steel will be selected depending on the stainless steel product we are making. Namely, the molds must be pre-designed according to the specific product. That means they are made to the exact shape and desired dimensions. In most cases, molds are divided into upper and lower concave molds – where the cavity follows the shape and dimensions we’ll be casting. Of course, this is preceded by some preparatory work such as turning, milling, etc.
● Tree setup and assembly
In the casting of stainless steel, we often use wax molds. As we have already mentioned, it is an industrial wax injected into a mold made of aluminum alloy. Once removed from the mold, the wax models are ready for inspection. That means that workers can check their precise dimensions, shape, and possible irregularities in places where they shouldn’t be. If they notice any errors, it is necessary to repair them – or completely discard such a mold because it will not be possible to use it in further procedures. If the unevenness or the shape can be repaired and brought into line with the standard – the workers will do it, and then such a model will be attached to the caster. Several wax models will be assembled in a particular order – and it resembles the crown of a tree. That’s why this procedure is called tree assembly.
When the so-called ‘tree’ is made – the models will be coated with industrial glue. Then, the so-called sandblasting procedure starts. It is the process of coating wax models with fine refractory sand – which is very resistant to high temperatures in furnaces. For this purpose, we usually use silicate sand because its grains are small, which makes the covered surface as smooth as possible – and at the same time, it is very resistant. After the sandblasting is finished, we wait for these models to dry naturally, which usually takes several hours. Of course, how long the tree models will dry depends on the shape of the model – that is, the complexity of the future product. After drying, there is another cycle of sandblasting in a slightly larger layer, which must also dry naturally.
We will only mention that, no matter how simple this step seems, it requires a lot of time because it is necessary to do the sandblasting in several cycles. Therefore, this step in the casting procedure takes several days.
Before we put the dried models in the oven, we should first coat them with a mixture of industrial latex. The reason for this step is to additionally harden the sandblasted molds since they continue their journey in the ovens. Given that there is industrial wax inside the cavity, it is clear that its melting temperature is much lower – and reaches somewhere up to 150 degrees Celsius. The melted wax is then extracted through special openings and channels – and this step is called deparaffinization. So, after that, we are left with only an empty sand shell, which is the key to the casting process. To further strengthen such sandblasted shells – it is necessary to additionally bake them at high temperatures of almost a thousand degrees Celsius.
● Stainless steel casting
Molten stainless steel, that is, steel with the addition of chromium or other elements that further strengthen it and make it anti-corrosive – is now poured into the sandblasted shells. After pouring it into molds in a liquid state, we have to wait for it to cool down and harden. After that, the sandblasted shell will be mechanically broken – and the cooled stainless steel takes the shape of the former wax mold. Next is cutting, then polishing, and our stainless steel casting is practically finished.
Only Testing Remains In The End
In the end, we can only test the obtained product on possible shortcomings. That can sometimes be small porous parts or parts with smaller unevennesses that can be aligned. More serious failures will return several castings to the stove to melt them and re-return them to the molds on the re-procedure.