What are the disadvantages of duplex stainless steel?

As a stainless steel material with high strength, excellent corrosion resistance and good welding performance, duplex stainless steel has been widely used in many fields. However, it also has some disadvantages, mainly including the following aspects:

Low heat resistance:

Compared with austenitic stainless steel, duplex stainless steel has lower heat resistance and is generally recommended to be used in working environments below 300°C. This limits its application in high temperature environments.

Large cold working hardening effect:

During cold working, the work hardening effect of duplex stainless steel is greater than that of 18-8 type austenitic stainless steel. This means that in the early stage of deformation of pipes and plates, a large stress needs to be applied to produce deformation, and the internal stress generated by stainless steel pipes and plates is also large. This increases the difficulty and cost of processing.

Existence of medium-temperature brittle zone:

Duplex stainless steel may have the problem of increased brittleness within a specific temperature range (i.e., medium-temperature brittle zone). This requires strict control of the process system of heat treatment and welding to avoid the appearance of harmful phases, thereby damaging the performance of the material.

High chromium content duplex stainless steel is difficult to process:

Duplex stainless steel with a chromium content of about 25% is more difficult to process than austenitic stainless steel during hot working. This increases the difficulty of material processing and manufacturing.

Relatively high price:

Due to the high content of alloy elements (such as Cr, Ni, Mo, etc.) in duplex stainless steel, its price is higher than some ordinary stainless steel materials. This increases the cost of use.

Application environment restrictions:

Although duplex stainless steel performs well in corrosion resistance, its corrosion resistance may still be subject to certain restrictions in certain specific media or environments. Therefore, when selecting materials, it is necessary to evaluate according to specific conditions of use.

In summary, duplex stainless steel has many advantages while also having some disadvantages. In practical applications, it is necessary to select suitable materials according to specific conditions and requirements of use, and take corresponding measures to overcome its shortcomings to ensure the normal operation and service life of the equipment.