Steel in Medical Technology

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Here in Germany, Goethe's "Götz von Berlichingen" was part of the standard school literature for quite some time. In adulthood, most people probably only remember two things: On the one hand, of course, the famous quote about licking an unsavory human body part and, on the other hand, perhaps the fact that the protagonist was also called the knight with the iron hand.

In fact, both the literary and historical Götz wore a prosthetic arm made of metal - a true masterpiece of medieval blacksmithing, equipped with lockable fingers that spring back into their original position at the push of a button. This Iron Fist can still be admired today in the Jagsthausen Museum.

Since then, however, a lot of water has flowed down the Lenne. Prostheses are no longer made of iron, but of modern high-performance materials. Doctors are able to replace entire joints and bones with implants. And the operation is no longer done with a rusty saw and a good sip of brandy, but with the help of precision instruments that can work with nanometer precision.

We owe this progress to a lot of clever minds, of course. However, not only from medicine, but also from metallurgy. Because numerous processes and treatment techniques were only made possible by a material with which we are very familiar: steel.


In this article we will tell you what is important
when it comes to medical steel,
why surgeons cannot do without their steel scalpels
and why a hip prosthesis made of iron would be
a really bad idea.


Medical steels: specialists for our health

We've said it before, but we're happy to repeat ourselves: not all steel is the same. Each individual alloy has different mechanical and chemical properties that predestine it for use in a specific area. It should come as no surprise to anyone that this principle applies particularly to a highly complex discipline like medicine.

That is why we fundamentally distinguish between two categories of medical steel: materials for instruments and materials for prostheses. Let's take a closer look at these two different steel families:

Stainless and shatterproof: steel for medical instruments

Steel for medical devices, colloquially also called surgical steel or simply medical steel, is predominantly a martensitic stainless steel. Its main alloying element is usually chromium, and its composition often contains larger amounts of nickel and molybdenum.

Hardness: The martensitic transformation of the steel creates a material of excellent hardness and strength. So if things get rough during an operation or the doctor hits a bone with the scalpel, his instrument will not break off and may endanger the patient's life.

Stiffness: Thanks to surgical steel, blades become stiff and their grind stays sharp for a long time. Only in this way is it possible for surgeons to carry out longer incisions precisely or to make the smallest scratches, as we know them from minimally invasive operations.

Heat and acid resistance: After, before and sometimes even during an operation, all instruments are thoroughly cleaned. Not only great heat is used, but also aggressive substances based on organic acids, which quickly turn an average butter knife into an unsightly heap of scrap metal. Tools made of medical steel, on the other hand, withstand numerous sterilizations thanks to their heat and acid resistance and work precisely and reliably for a long time.

Corrosion protection: The human body is also a veritable wet biotope - as a reminder: We consist of up to 80 percent water, our blood plasma even up to 91 percent. Medical devices are therefore exposed to high levels of moisture during work; Not to mention the subsequent cleaning. So it's a good thing that stainless steel doesn't rust.

Scratch-resistant surface: Chrome also gives medical instruments a scratch-resistant surface. This is important because even the smallest groove in a tool can become a breeding ground for bacteria that are quite safe from sterilization deep in the material. And nobody wants to get a hospital germ because they have had a varicose vein removed.

Hygiene: Speaking of bacteria - the little creeps hardly stand a chance on the surface of surgical steel, because the alloy has an antibacterial effect.

Bonus tip: If you are now thinking about a surgical steel piercing because of its numerous positive properties, we strongly advise against it. Many people have an intolerance to the nickel content in many stainless steel alloys. Please always choose jewelry made of horn or plastic for your first piercing!

Any steel can therefore by no means be considered for medical instruments, only special steels that meet the high requirements of medical technology. You will find these materials in our portfolio under the material numbers 1.4057, 1.4545 and 1.4310.

Biocompatible and bioadhesive: implant steel

Although stainless steels are also used for numerous implants and prostheses, unlike surgical steel, they go through an austenitic manufacturing process, for example the electroslag remelting process. These materials are less hard and therefore easier to form than martensitic steels, which makes them ideal for use as individually adapted implants.


They also have the following advantages:

Strength: Strength describes the resistance to mechanical stress. A new shoulder joint should therefore have good strength values, because it is almost constantly exposed to movement. Prosthetic steel meets this requirement and is therefore particularly durable.

Protection against corrosion: You remember, our body is quite humid. Implant steel therefore always has excellent corrosion properties. After all, nobody wants the new hip to have to be replaced after six months because of rust damage.

Acid resistance: Acids are formed in many parts of our body, not just in the digestive process. They also arise, for example, as a waste product of cellular energy production and especially when proteins are broken down. Although these acids are quickly neutralized by bases, contact with the implant can never be completely ruled out.
Furthermore, in modern medicine, implants are covered with a fine layer of anti-inflammatory substances in order to curb the body's immune response. This includes hyaluronic acid. Acid resistance is therefore an essential property of implant steel.

Biocompatibility: Biocompatible means that our body does not fight and reject the foreign substance. For example, if you stick a splinter of wood in your finger, your immune system will respond with inflammation. However, since prosthetic steel is highly biocompatible, the erythrocytes keep their membranes still and do not attack the new body part.

Bioadhesion: Bioadhesion, in turn, means how well the human body can incorporate a prosthesis into the natural tissue. Unfortunately, stainless steels only have moderately good adhesion properties and therefore usually have to be fixed with cement. However, there are even more modern, albeit more expensive, titanium-based materials that have such high bioadhesion that they can be completely incorporated into the natural bone structure after a short time and without any cement.

Implant steels are just as specialists in their field as surgical steels and need their very own properties to be suitable for use in the human body. That is why they also have their own standard, namely ISO-5832. In our materials database you will find suitable stainless steels under the material numbers 1.4441 and 1.4472.

Medical steels: You can't do without them

We hope that we have brought you a little closer to the importance of special steels for our modern medicine. Without the knowledge of metalworking that has been accumulated over centuries, the chances of survival after an operation would be significantly worse and many people would have to spend their lives with severe restrictions.

Steel not only keeps the industry running, but also you and us. A more versatile material is hard to find. Finally, as always, we would like to point out: If you have any questions or want to place your order for our special medical steel, we look forward to hearing from you!