Introduction
Cr13Ni8Mo2Al is a ferrite stainless steel, also known as X5Cr13Ni8Mo2Al or PH13-8Mo, which belongs to the ferrite-austenitic dual-phase stainless steel family. This grade of stainless steel exhibits excellent high temperature strength and oxidation resistance properties which makes it ideal for use in a variety of industrial and consumer products.
Composition
PH13-8Mo consists of approximately 13.0% chromium, 8.0% nickel, 2.0% molybdenum, and 1.0% aluminum. These components account for the balanced overall composition of the material and are the primary source of its strength and corrosion resistance properties. This grade falls in within the unified numbering system (UNS) and is represented as either S13050 or S13008, depending on higher concentrations of aluminum and other elements.
Properties
PH13-8Mo has a relatively low yield strength but exhibits an excellent combination of high tensile strength, corrosion resistance, and thermal stability. The property combination is well suited for applications where a lightweight and corrosion resistant material is preferred. The corrosion resistance is a result of the combined presence of chromium, nickel, and molybdenum which form an oxide layer that protects against hostile environments such as chlorine, sulfuric, and hydrochloric acids. The thermal stability of this grade allows it to tolerate higher operating temperatures such as those found in chemical and industrial process settings up to a maximum of 760°C (1400°F).
Forming/Machinability
Due to its relatively low yield strength and hardness, PH13-8Mo is relatively easy to form and work with compared to other steels. There are a few methods that can be utilized during the forming process such as rolling, bending, extruding, and cold drawing. When it comes to machinability, the material rates in the average range among stainless steels, making it relatively easy to machine compared to other grades.
Weldability
The desired weldability of the material is expected to be low due to its higher carbon and chromium content, but this can be improved through the use of weld rods and other alloys. Welding PH13-8Mo can be done through manual, semi-automatic, and automatic welding processes. It is important to preheat and post-weld heat treat all joints to relieve residual stresses and ensure the integrity of the weld.
Applications
PH13-8Mo is a versatile grade of stainless steel that is well-suited for use in many industrial applications. It is commonly used for fabrication and construction of chemical process vessels, industrial process piping, steam turbine components and petrochemical piping. Other applications include machinery components, fasteners, and architectural fixtures.
Conclusion
Cr13Ni8Mo2Al (PH13-8Mo) is a ferrite stainless steel that exhibits excellent high temperature strength, thermal stability, and corrosion resistance. The material is relatively easy to form and machine and can be used in a variety of industrial applications such as chemical process vessels, industrial process piping, and steam turbine components. It is important to preheat and post-weld heat treat all joints in order to ensure the structural integrity of the weld and relieve residual stresses.
