No you will probably have to make every other leaf in some thing softer like Tufnol phosphor bronze or beryllium copper this will keep the strength down to a useable level and keep the number of leafs scale. You are being affected by the cube rule. Several of my wagons have two steel leafs and five Tufnol. One of the benefits of leaf springs is the friction between the leafs acts as a mild shock absorber so not such a bouncy ride as coils!