I've not heard of one.
Why would you want a steel charging handle? Given the dimensions, I can't imagine it would be stronger by any useful amount.... but I have been wrong before.
Would steel cause any wear issues within the reciever? That would be my biggest concern. I've been shopping around for a gas buster or a gunfighter model and haven't seen anything steel mentioned.
All content of this site is copyright 2003 - 2017 AR-10(T)™, AR-10™, are trademarks of ArmaLite, Inc.® AR10T.com is NOT endorsed or affiliated with ArmaLite, Inc.®
About AR10T.com
AR-10(T) is a community focused on rifles, optics, scopes, gear, accessories, and components used by the professional operator and skilled marksman. Enthusiasts, shooters, and gunsmiths alike contribute to our gallery, articles, and reviews Thank you for visiting!