Using the four species of alloy tool steels, which were presumed to be representative for steels for manufacture of block gauges, some standard block gauges of Johansson type with a length of 25mm were experimentally made and subject to various heat treatments. Deformations accompanied with these different heat treatments were measured and the dimensional change owing to room temperature aging after hardening treatment was observed for a period of more than 3 years.
It was confirmed from the experimental results that the practically effective way of stabilization of the dimension consisted either in a method of repeated temperings after various quenchings or in the so-called cyclic treatment which had been composed of subzero treatment and tempering after various ways of quenching. Steels subject to such heat treatments presented a dimensional change of less than about 0.05μ after being kept untouched for about 3 years. And furthermore various conditions of the heat treatments of dimensional stabilization were determined and the interpretation concerned was made clear.