W1 steels are capable of hardening to high surface hardness and soft core, which is useful in some shock applications. They are low-cost tool steels with fair to good wear resistance as carbon content increases. As they are water quenched and have poor dimensional stability, their use is limited to fairly uniform sections with a minimum amount of stress risers; in other applications quench cracking can occur. Figure 1 shows an isothermal transformation diagram for a W1 steel.
For more information, click on the link below (subscription required). Then scroll to Figure 1.Rafael Agnelli Mesquita; Reinhold Schneider; Cristiane Sales Gonçalves, *Heat Treating of Cold-Work Tool Steels — Low- and Un-Alloyed Water and Oil Hardening Steels*, ASM International, 2014 [https://doi.org/10.31399/asm.hb.v04d.a0005972](https://doi.org/10.31399/asm.hb.v04d.a0005972)
