I’ve been googling, and found the curvy things are “Rail Anchors”, of a type called “Unit 5” or “Unit V”, made by several manufacturers. They are definately “spring steel”, for example, might be made of this type of steel: 60Si2MnA of hardness HRC 42-50 which can be raised into mid 50s hardness by careful heat treat normalizing.
A lovely post on iforgeiron.com says they are pure 1060 steel. They might be called “creepers”. They forge well at orange to yellow yeat, and can become tools if properly heat treated. They can make long tanto blades. Maybe crossbow limbs. Further posting about these said to normalize and temper according to this recipe:
Forge to shape without much regard for forging temp
Normalize in heat treat oven at 1550, 1525 and 1500 for each step and allow to air cool
Heat to 1500, soak for 10 minutes and quench in parks 50 oil
Temper 2 times at 425 for two hours each
In a cake pan with water, keep the lower 1/3 of the blade in the water and heat the spine with a regular propane torch as hot as you can get it evenly(it is hard for me to get it much past blue due to the heat sink of the water but I do rock the 1/3 in and out of the water to get it hotter)
Make a thin flat grind and then covex the edge on a slack belt.