The resistance of the alloy to localized tubing corrosion can be approximated from its chemical composition by calculating the alloy's pitting resistance equal number (PREN). The most often used relationship is: PREN = %Cr + three. Welded tension tubing is used in a wide variety of industries and conclude-use markets http://valvesandfittings53815.educationalimpactblog.com/12034798/not-known-details-about-stainless-teel-tubing