New medical grade heat treat process for bright 17-7 PH stainless steel

August 19, 2014

Using advanced gas cooling technology, Solar Atmospheres, Souderton, PA, USA, has developed a unique three-step heat treat process to austenite condition, in situ cool, and bright age harden 17-7 precipitation hardenable (PH) stainless steel in a vacuum furnace without breaking vacuum.

This, states Solar, is highly desirable because it is difficult to keep 17-7 bright during the PH treatment after breaking vacuum and exposing parts to ambient atmosphere required for adequate cooling where it can discolour due to oxidation.

Working with the medical industry, a new in situ process was developed where desirable mechanical properties could be consistently obtained. With this new process, a new medical device design could be based on the established set of mechanical properties and the medical company would reap the benefit of reduced costs owing to reduced pricing associated with the new in situ, three-step process.

17-7 PH is classified as a semi-austenitic stainless steel that has expansive use in aerospace and growing new applications in the medical industry. The reason for this is 17-7 PH’s attractive combination of properties including very high, spring-like strength, good ductility, and excellent corrosion resistance due to its high alloy content. In order to obtain these properties, however, 17-7 must be heat treated in a more controlled manner than many other alloys.

Solar Atmospheres performed a recent study that showed its vacuum heat treatment technology offers a unique processing advantage to achieving these highly desirable properties. As a baseline, the new set of mechanical properties and microstructure characteristics were compared to standard Condition TH 1050, the most common condition specified in industry for 17-7 PH.

A three-step austenite conditioning, in situ cooling and precipitation hardening process resulted in a new condition of 17-7 that Solar Atmospheres has coined SH 950. Compared to 17-7 Condition TH 1050, Condition SH 950 showed comparable yield strength, higher tensile strength, and on average twice the ductility.

These tensile properties were obtained with two different heats of steel with three tensile specimens tested for both heats and conditions resulting in 12 separate tensile test results. The findings are both consistent and inspiring. The microstructure of SH 950 also appeared superior with respect to lower delta ferrite stringers being present.

The results associated with Solar’s Condition SH 950 for 17-7 stainless steel indicates that a new medical device design could be based on the newly established range of mechanical properties. This new vacuum heat treatment technology offers a unique processing advantage for achieving desirable properties while cost effectively producing bright, non-discoloured parts.

www.solaratm.com     


Powder Metallurgy Review magazine:

Your email address:


Useful links: Download PM Review magazine | News headlines | Browse articles 


Powder Metallurgy Review magazine cover

In the latest issue of PM Review…

Download PDF

Extensive Powder Metallurgy industry news coverage, and the following exclusive deep-dive articles and reports:

  • Hot Isostatic Pressing for the production of large, near-net shape components
  • Safeguarding PM part usage in a new automotive industry
  • How to make metal powders., Part 3
  • Company profile: Jiangxi Yuean Advanced Materials

The latest news from the world of metal powders, delivered to your inbox

Don't miss any new issue of PM Review, and get the latest industry news. Sign up to our weekly newsletter.

Sign up

From the industry…

Discover our magazine archive…

The free-to-access PM Review magazine archive offers unparalleled insight into the world of Powder Metallurgy from a commercial and technological perspective through:

  • Reports on visits to leading PM part manufacturers, metal powder manufacturers and industry suppliers
  • Articles on technology and application trends
  • Information on materials developments
  • Reviews of key technical presentations from the international conference circuit
  • International industry news

All past issues are available to download as free PDFs or view in your browser.

 

Browse the archive

 

Looking for PM production equipment, metal powders, R&D support and more?

Discover suppliers of these and more in our
advertisers’ index and buyer’s guide, available in the back of PM Review magazine.

  • Powders & materials
  • Powder process, classification & analysis
  • PM products
  • Atomisers & powder production technology
  • Compaction presses, tooling & ancillaries
  • Sintering equipment & ancillaries
  • Post-processing
  • Consulting & toll sintering
Download PDF
Share via
Copy link