The key difference between Hastelloy and stainless steel is that Hastelloy shows an outstanding corrosion resistance compared to stainless steel.
Alloys are mixtures of different chemical elements, including metals as the major component and nonmetals as a minor component. Hastelloy and stainless steel are two such alloys which are well known for their excellent corrosion resistance. However, Hastelloy is considered to be more effective for the corrosion resistance than stainless steel due to its specific composition, which has more nickel in it.
CONTENTS
1. Overview and Key Difference
2. What is Hastelloy
3. What is Stainless Steel
4. Side by Side Comparison – Hastelloy vs Stainless Steel in Tabular Form
5. Summary
What is Hastelloy?
Hastelloy is a nickel-based alloy which shows excellent corrosion resistance. We call it a superalloy because it can withstand high temperatures, high stresses, and often highly oxidizing atmospheres. This material is available in the form of plate, sheet, bar, pipe, tube, etc. Some important properties of this alloy are as follows:
Properties of Hastelloy
- High resistance to stress
- Outstanding corrosion resistance
- Excellent stress corrosion cracking resistance
- High resistance to acids
- Ease of welding
- Ease of fabrication
- High resistance to oxidation (at high temperatures)
Figure 01: A Hastelloy Ball Valve
Primarily, this alloy is prepared from nickel, along with small percentages of some other elements such as chromium and molybdenum. The production is a complex process that involves the mixing of basic ingredients with several chemical elements such as tungsten, carbon, titanium, aluminium, manganese, copper, cobalt, chromium etc. The industries that have applications of Hastelloy include chemical processing industry, aerospace, pharmaceutical industry, etc.
What is Stainless Steel?
Stainless steel is an alloy of steel with a high chromium content. Therefore, it has great corrosion resistance. Typically, this alloy contains about 10.5% chromium and 1.2% carbon by weight of the alloy. With increasing chromium content, the corrosion resistance also increases. Moreover, the addition of some molybdenum into this mixture can increase the resistance against acids. Stainless steel is available in the forms of sheets, plates, bars, wires, tubes, etc.
Figure 02: Surgical Tools made of Stainless Steel
The production process of stainless steel has several important steps: melting and casting, forming, heat treatment, descaling, cutting and finishing. Furthermore, the basic raw material for this production are iron ore, chromium, silicon, nickel, carbon, nitrogen, and manganese. By adding varying amounts of these elements, we can obtain different properties as desired. For instance, adding more nitrogen will increase the tensile strength.
What is the Difference Between Hastelloy and Stainless Steel?
Hastelloy is a nickel-based alloy which shows excellent corrosion resistance while stainless steel is an alloy of steel with a high chromium content and consequently a great corrosion resistance. Moreover, the key difference between Hastelloy and stainless steel is that Hastelloy shows an outstanding corrosion resistance in comparison to stainless steel. Moreover, the major components of Hastelloy are nickel, chromium and molybdenum while the major components of stainless steel are iron, chromium and carbon.
When considering the applications of these materials, Hastelloy is used in industries such as chemical processing industry, aerospace, pharmaceutical industry, etc. whereas stainless steel is used in architecture, plumbing, pulp and paper industry, chemical processing industry, food and beverage industry, etc.
Summary – Hastelloy vs Stainless Steel
In brief, Hastelloy and stainless steel are alloy materials. Hastelloy is a superalloy while stainless steel is an alloy of steel. Both these are resistant to corrosion, but the extent of resistance is different from each other. In conclusion, the key difference between Hastelloy and stainless steel is that Hastelloy shows an outstanding corrosion resistance in comparison to stainless steel.