We had 5,000 pcs of these custom 4037 alloy steel flat socket head screws produced in the USA for our aerospace customer.  ASTM A574 4037 material was used for the production and the cadmium plating was dome per AMS-QQ-P-416A TYpe II, with thickness at 0.0005-.0008".  Heat treat was performed to get the hardness of the parts to Rc 41-45.  The socket drive was cold formed and the thread rolled, both at the same facility.  Full certs were provided with the parts per our customer's requirements.