17-7 PH Stainless Steel Tubing
17-7 stainless steel tube includes aluminum in the composition and has good corrosion resistance with excellent strength and hardness characteristics. It is otherwise known as 17-7 PH, UNS S17700, or AISI 631. 17-7 tubing has minimal distortion and maintains its properties at high temperatures.
Perhaps its best-known quality is the ability to increase hardness and tensile strength via post-cold working heat treating (17-7 is also known as 17-7PH, which stands for precipitation hardening), which can increase mechanical strength characteristics of the tubing beyond 300 series stainless, and to levels unachievable by cold working alone. The precipitation hardening nature of 17-7 tubing offers an ideal combination of characteristics of both martensitic and austenitic stainless steels: excellent corrosion resistance with high cold worked strength that can be increased via heat treatment. The practical impact is that 17-7 tubing permits products to be designed with thinner walls and lighter overall weights without sacrificing mechanical qualities.
17-7 stainless tubing can be offered in several temper options, including annealed (Condition A), drawn hard temper (condition C), or heat-treated (Condition CH-900). CH-900 heat treatment occurs after the tube reaches condition C, and preferably this treatment at 900 degrees Fahrenheit is performed in a vacuum furnace to reduce any discoloration on the tube surface. With good machinability characteristics, 17-7 tubing can be fabricated into products using typical subtractive manufacturing processes like grinding, milling, turning as well as other methods like EDM, ECM or laser.
17-7 SS Tubing Features & Applications
Standards often referenced include ASTM F899 or AMS 5568. With high strength, good formability, and excellent fatigue resistance, 17-7 PH stainless steel tubing is often used in the following applications:
- Orthopedic/sports medicine applications
- Endoscope products
- Surgical instruments including cutting tools
- Robotic medical instruments
- Bone biopsy needles
- Aerospace applications
17-7 SS tubing is welded from strip stock, plug drawn in coil form, annealed as needed in order to meet customer temper requirements, and offered in straight lengths or coil form. CH-900 heat treated 17-7 tube is limited in terms of lengths available in straight length form due to vacuum furnace dimensional constraints.
VIEW STAINLESS STEEL SIZES
Learn more about the most popular and widely used dimensions in the industry.