Welding Tips and Tricks

Hello,
Came across an old box of tig filler wire and was looking for some help in identifying it and maybe its applications. All that was written on the box was Cert 77, mild. I'm thinking it means CERTANIUM 77. I did Google that but didn't come up with any conclusive information. Any help is appreciated. Thanks in advance. Mike

Here is a fairly decent list of certanium filler. Didn't see 77 though.

http://www.kenteurope.eu/uk/industrial/welding.php

Certanium maintence welding guide lists it as Certanium 701T (formerly 77) 70,000 psi yeild. Edit to add Mild Steel.

Do you have any photos of it? I've never come across a Cert. 77.