I am aware of only two suppliers of this type of wire, which is basically music wire (patented 1% carbon steel)with higher levels of manganese and silicon for additional strength. One is in the U.S. and one is in Germany. There are no consensus standards that cover the requirements for this type of material. I would use ASTM A 228 and DIN 10270-1 as a starting point, and then discuss additional requirements with the supplier. The following is the contact information for Mount Joy Wire in the U.S. (I'll have to look at my records for the German supplier):
Mount Joy Wire Corp.
1000 East Main Street
Mount Joy
Pennsylvania
17552-0505
USA
Phone: 717-653-1461
Toll-free: 800-321-2305
Fax: 717-653-6144