Quality raw material barstock is at the core of the Swagelok tube fittings' high performance and consistent reliability. Swagelok implements very tight controls on procurement of 316 stainless steel material and the inspection steps used to validate all material.
- Swagelok has multiple restrictive requirements on the purchase of 316 Stainless Steel raw material, including alloy content and certain mechanical properties that are tighter than minimum ASTM specifications. Because full heat quantities are procured, the approved mills are able to adhere to these requirements . This material cannot be purchased “off the shelf” and is unique to Swagelok.
- Two of the more important ingredients in stainless steel are chromium and nickel for corrosion resistance and ductility. Although ASTM requires a chromium level between 16 to 18%, many manufacturers levels trend closer to the 16% minimum. For many years, Swagelok has maintained and controlled chromium content as a minimum of 17%
- ASTM states that nickel levels in stainless steel range between 10 to 14%. Once again, there is an industry trend toward the minimum of 10%, but Swagelok has held its minimum nickel range at 12%.
- Elevated corrosion resistance and uniform manufacturability are obtained when machining Swagelok tube fitting components. The benefit to an abundance of chromium is to provide the necessary corrosion resistance needed in applications where stainless steel products are used. Nickel stabilizes the austenitic structure of stainless steel and helps to provide a more ductile or non-brittle material, especially in a wider range of temperatures and system media.
Generic 316 stainless steel metallurgical performance is not what it used to be. As you can see in this example, high quality raw materials matter.