Checking ASM's Worldwide Guide to Equivalent Irons and Steels, 3rd Ed., shows that X17CrNi16-2 falls into the UNS S43100, AISI 431, and EN10088-3 categories. Check with your suppliers to see if they can supply their S43100/AISI 431 material to meet your specific requirements of X17CrNi16-2.
X17CrNi16-2 is an Italian specification. A quick internet search provided 2 good references for equivalents:
The one thing that you will need to double check is the carbon level. This alloy is made with a number of different carbon levels for different applications.