Percentage of carbon in stainless steel to avoid brittleness What is the maximum percentage of carbon allowed in stainless steel 202 so that it does not cause brittleness?
All  standardised grades of alloys have definite limits of composition. 
If its common, then a quick search will find it. 0.15% is the specified limit for SS202. 

http://www.azom.com/article.aspx?ArticleID=8209

Whether its brittle or not depends on what you mean by brittle and its thermal processing. Its a martensitic stainless steel so note the details in azom and that it will be more brittle when hardened as described.