It depends on the type of stainless steel being used for races. Austenitic stainless steels (2** and 3**) won't magnetise, but ferritic stainless steels and martensitic stainless steels (groups 4** and 5**) are magnetic. Precipitation hardening stainless steels and duplex stainless steels need to be considered on a individual case by case and at the operating temperature.
300 series austentics will magnetize when cold worked, not to the level of ferritic stainlesses, but enough to throw off sensetive magnetic sensors. There are 300 series that cold work faster than others however. Nickel alloys will not magnetize but pure nickel is very magnetic. The addition of significant alloy content makes it nearly completely non-magnetic.
