Verification of duplex steels by its nitrogen content

SPECTROTEST, the flagship mobile metal analyzer from SPECTRO Analytical Instruments, is the ideal instrument for onsite quality control. It helps prevent grade mix-ups of incoming materials on the production floor, at the shipping dock, or in the welding shop.

A critical task: onsite identification of duplex steels – but not for SPECTROTEST.

SPECTROTESTSPECTROTEST has the ability to accurately identify duplex steel grades onsite, to differentiate them from other stainless steels and to verify the grade specifications — by measuring their content of alloyed nitrogen. That’s something that handheld instruments, or even other portable and mobile spectrometers just can’t do.

Based on advantages such as an optical system with high stability, plus the widest wavelength range in its class (174 nanometers to 670 nanometers), SPECTROTEST performs this difficult identification with ease: in just 10 s . It also offers shortest measuring times starting at 2 seconds in arc mode, and 5 seconds in spark mode with argon atmosphere. This high-productivity throughput is critical when large numbers of samples must be tested.

Duplex steels must be accurately verified to ensure the right application match, to assess weldability, or to prevent damage to processing tools such as saws or shears. Prized for their mix of excellent corrosion resistance with high strength, these steels combine austenitic and ferritic grades structure to achieve their desired toughness and processing characteristics. (Although their high strength means more difficult formability and machinability plus comparatively lower ductility (than pure austenitic grades), limiting use in applications where these requirements are paramount.) Nitrogen is added as a stabilizing alloy element for its low cost compared to nickel, and for alloys’ weldability and their quality of requiring less thickness and weight to realize the same strength. Typical nitrogen content in duplex/ super duplex steels ranges from 0.08% to 0.40%; 0.30 – 0.60% for hyper duplex steels.

These steels are widely used in applications including pharmaceuticals and biotechnology; oil and gas, petrochemicals, and chemicals; offshore, marine, and other corrosive environments; pressure vessels and structural components; and large constructions such as bridges, storage tanks, and wind turbines. SPECTROTEST can provide fast, reliable identification of duplex steel grades for all these purposes and more.

High stability and a wide spectral range: recent testing shows that field-proven SPECTROTEST technology provides reliable results when measuring nitrogen in duplex steels. Measurement time is 10 s for each single measurement in spark mode.

Download the SPECTROTEST product bulletin here.

  • Capabilities that other mobile instruments can’t match
  • Precise identification of duplex steels
  • Easy, accurate measurement of the key grade differentiator: nitrogen content
  • Unequaled analytical stability and range in a mobile analyzer