Tensile properties in W-containing high Co–Ni steels

The effect of the addition of Cr on tensile properties in high Co–Ni secondary hardening steels containing W has been seen in as-quenched and aged conditions. Two kinds of Co–Ni steels, containing only W (W steel), and W and Cr (WCr steel), were severely multipass-rolled in the unrecrystallized region, followed by direct quenching. Both steels showed secondary hardening peaks with precipitation of fine M2C carbides during aging. The secondary hardening reaction was promoted by the Cr addition although there was some decrease in tensile strength. In terms of tensile behavior, it is pointed out that both yield strength and yield ratio (YS/UTS) were considerably decreased by the Cr addition. In addition, the tensile strength to hardness ratio is larger in the as-quenched condition compared with the aged condition.