Shortcomings of duplex stainless steel pipe

Duplex stainless steel pipes offer a combination of high strength and corrosion resistance, making them popular in various industrial applications. However, they do have some shortcomings, understanding these shortcomings is crucial for selecting the appropriate material for specific applications and ensuring the long-term performance and reliability of duplex stainless steel pipes.

Cost:

Duplex stainless steel pipes are generally more expensive than traditional austenitic or ferritic stainless steels due to the complex manufacturing process and the higher cost of alloying elements.

Weldability:

While duplex stainless steels can be welded, the process is more challenging compared to other stainless steels. Special attention is required to control heat input and cooling rates to avoid issues like weld decay or the formation of unwanted phases that can reduce corrosion resistance and mechanical properties.

Susceptibility to Stress Corrosion Cracking (SCC):

Under certain conditions, such as the presence of chlorides and tensile stress, duplex stainless steels can be susceptible to stress corrosion cracking, particularly in hot environments.

Limited Temperature Range:

Duplex stainless steels have a limited temperature range for optimal performance. They are not suitable for very high-temperature applications (above 300°C) as they can undergo embrittlement due to the formation of intermetallic phases.

Complexity in Manufacturing and Quality Control:

The production of duplex stainless steel requires precise control over the composition and heat treatment processes to achieve the desired phase balance (austenite and ferrite). This complexity can lead to higher costs and stringent quality control measures.

Impact Toughness at Low Temperatures:

Although duplex stainless steels generally have good toughness, their impact toughness can decrease significantly at very low temperatures, limiting their use in cryogenic applications.