Metlab, a Philadelphia, Pa.-based commercial heat treater, recently heat treated the custom-fabricated leaf springs of an antique Alfa Romeo sports car. The leaf springs – made from HR-5160 steel – were patterned after the original springs, which were too worn to be reused during the car’s restoration. The steel was cut to length, and then eyes were hot formed on the springs. The replacement springs were hardened and press quenched into the shape of the spring using a pencil-drawn template made from the originals. Then they were tempered to a final hardness of HRC 28-32, duplicating the hardness as measured on the samples.