Composition and properties

AISI 317L (1.4438) stainless steel is a low-carbon austenitic alloy, with high chromium (up to 18%) and nickel (up to 13%) content. The percentage of carbon in steel does not exceed 0,03%, and it is completely bound by iron, representing a solid solution of cementite in the base metal matrix. Steel differs from similar grades by the increased (up to 3%) content of molybdenum.

The chemical composition of the alloy determines its following features:

• Increased resistance to corrosion, including high-temperature corrosion.
• High acid resistance.
• The strength at elevated temperatures up to 1300...¹⁸⁰⁰⁰ С for long-term operation of products.
• Strength under prolonged loads not exceeding the tensile strength limit.
• Satisfactory weldability.

When melting in vacuum furnaces the alloy is additionally saturated with nitrogen, which is further bound in high-strength chromium carbides. The presence of molybdenum promotes the formation of intermetallic compounds, which further enhances heat resistance.

Application

Pipe made of steel AISI 317L (1.4438) is widely used in the manufacture of pipelines, which are systematically pumped liquid aggressive media, including at elevated temperatures. In this case, the growth and development of pitting corrosion sources is slowed down, resulting in increased service life of pipelines. Consumers are the gas and oil refining industry, as well as the production of various chemical reagents - plant protection products, pharmaceutical semi-finished products , etc.

Circle of this alloy (domestic substitute - steel 03Х19Н13М3, produced under special TU) is used in the manufacture of high-strength valves. At the same time the technology of cold and hot volumetric stamping is implemented.

Wire made of AISI 317L (1.4438) steel is used in high-precision measuring devices and apparatuses which carry out continuous control over the functioning of steelmaking complexes.