What Is The Difference Between Surgical Steel & Stainless Steel?

What Is The Difference Between Surgical Steel & Stainless Steel?

What is Surgical Steel?

Surgical steel is a grade of stainless steel that is used in biomedical applications. It is an iron-based alloy that contains chromium, molybdenum, nickel, and small quantities of carbon. This alloy is generally made by vacuum melting technique, due to this an alloy with smaller grain size and fewer impurities is produced. Carbide accumulation within the grain boundaries, formed due to carbon in surgical grade stainless steel weakens the material and due to this carbon content is strictly limited in the alloy. Chromium content in the alloy creates a protective oxidation layer on the implant that resists perforation by corroding ions. Surgical stainless steel is widely used in orthopedic implants. Stainless steel grade 304 is widely used in medical applications. Normally surgical steels are those that have an excellent amount of corrosion resistance. Among all the stainless steel, surgical steel is considered the most expensive grade of steel.

What is Stainless Steel?

While all the surgical steels are a grade of stainless steel, not all the stainless steels are surgical steels. Primarily, stainless steel is made from iron and carbon with the addition of chromium, nickel, and other elements depending on the grade of steel. Once chromium is added to steel, it forms a protective layer of chromium oxide that improves the corrosion resistance properties of the steel.

Stainless steel is normally classified into four categories such as.

  1. Austenitic steel: austenitic is considered the most widely used type of stainless steel, that has excellent resistance to corrosion along with great mechanical properties over a wide range of temperatures. Normally austenitic steels have applications in architectural facades, construction, industrial piping and vessel, houseware, etc.
  2. Ferritic steel: ferritic stainless steel has properties that are similar to mild steel, but have better resistance to cracking, heat, and corrosion. This steel is commonly used in indoor architectures, boilers, washing machines, etc.
  3. Martensitic steel: martensitic steel is considered as very hard and strong steel, but lesser resistant to corrosion if compared to austenitic steel or ferritic steel grades. This grade of steel generally contains 13% of chromium and is used to make turbine blades and knives. 
  4. Duplex steel: duplex stainless steel is normally a composite of ferritic steel and austenitic steel that makes it both flexible and strong. Duplex steel is commonly used in petrochemical industries, shipbuilding, pulp, and paper industries.

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