Metlab, Philadelphia, recently heat-treated custom fabricated leaf springs of an antique 1932 Alfa Romeo sports car. The springs were fabricated for a Pennsylvania based automobile restorer. The leaf springs, made from HR-5160 steel, were patterned after the original springs, which were too worn to be reused. 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.
Another recent project included the case hardening of reground lifters from a 1962 Rolls-Royce Silver Cloud engine. The lifters, which exhibited about 0.010-in. wear, were reground to make them all uniform in size. However, the grinding removed the hardened case, hence the lifters had to be recarburized and rehardened. As-measured surface hardness was HRC 62.
In addition, Metlab is often called upon to nitride O.E.M. as well as reground camshafts, crankshafts, and other engine components to restore these parts to original factory specifications. Camshafts are typically manufactured from 4140 or 4340 pre-heat-treated steel. This steel has a hardness of HRC 28 – 32. Nitriding results in a surface hardness of HRC 60+ and a case depth of up to 0.020 in., providing significant wear protection for the cam lobes and gear teeth.
In addition to hardening and surface treatment services, Metlab offers cryogenic processing on automobile engine, transmission, and brake parts for improving their performance extending their useful life.
