Ch. 75 Metallic Instruments and Implants Flashcards
the suffix letters A, B, or C define an increasing carbon range for a given alloy (420C > 420B > 420A) and the chromium range increases as the three-digit 4XX number increases (440 > 431 > 420).
For a given alloy, the hardness typically decreases as the tempering temperature increases.
Precipitation hardenable (PH) stainless steels contain substantial amounts of chromium, nickel, and copper, plus controlled levels of secondary elements
PH stainless steels are used for a variety of noncutting instruments that require a moderate hardness level.
The PH grades do not contain a high carbon content, so edge retention and wear resistance are inferior when compared with the 400 series martensitic compositions.
For multi-component devices, such as plates and screws, it is not advisable to mix stainless steel and titanium implants because an accelerated form of corrosion, known as galvanic corrosion, can occur.
