Our shop mainly deals with common steel (S355) and chrome-moly (42CrMo). To this day, I haven't found a realiable method to tell the difference between the two when using hot rolled bars. I have tried toughness testing (hammer-rod etc). and spark testing ,but I simply cannot tell the difference. Taking a chip with the machine seems to be the only way (machined chromoly surface is brighter). Of course the steels should be stored separately, but it simply does not work here.
What's your suggestion?