Subject: Re: Titanium and Tungsten

From: [email-masked] (Dan Nibbelink)
Date: Mon, 29 Jul 1996 18:40:51 -0600

>Dear Dan,
>
>Could you restate this? Sounds like good info, but I can't make heads
>or tails of where the health risks come in. Seems like two sentences
>got spliced or something.
>
>
>> Titanium: the health risks from forging titanium are from the
>> alloying elements, notably chromiun is "beta phase" alloys such as
>> Ti013V-11Cr-3Al. Titanium will change from alpha to beta phase when
>> heated, and back when cooled; this is not a health risk. "Beta"
>> alloys do not change because of the alloying elements. CP
>> (commercially pure) and Ti-6Al-4V (most common Ti alloy) do not pose
>> health risks.
>
>
>--
>Steven O. Smith
>[email-masked]
>
>
Alpha phase is the normal phase of CP titanium at room temperature. When it
is heated it will change to beta phase, and when cooled, revert to alpha
phase. This is similar to the behavior of steel.

Some alloys of titanium stay in the beta phase at room temperature and are
refered to as "beta" alloys. They stay in the beta phase because of the
alloying elements. One of the elements used for this is chromium -- 11% Cr
in Ti13V-11Cr-3Al. It is this chromium which presents the health risk;
apparently it can be released to the atmosphere during heating and/or forging.

Dan Nibbelink