Cr-Ni-Mo Forged
Backup Rolls (CrNiMo BUR) are used where standard Cr-Mo forged backup rolls
approach their limits, especially in hardness support through long campaigns,
while maintaining sufficient load-bearing stability for reliable. Backup roll performance remains governed by load-bearing
stability, internal integrity, and subsurface fatigue resistance.
Cr-Mo Forged
Backup Rolls are the standard solution for most rolling mills, providing a
balanced combination of toughness, load-bearing stability, and tolerance to
instability. Cr-Ni-Mo Forged Backup Rolls are more case-specific and less
tolerant. They
are used when deeper and more stable hardness support is required, provided
that tighter mill and roll-shop control can be maintained.
The primary difference
from standard Cr-Mo backup rolls lies in alloy composition. Nickel,
together with adjusted chromium and molybdenum content, increases hardenability
and promotes a deeper hardening response through the section. The objective is
improved hardness and stable subsurface fatigue performance, while maintaining
sufficient toughness and structural reliability.
Cr-Ni-Mo Forged Backup Rolls are not defined by a fixed grade structure. In practice, they are
produced from alloy steels tailored for roll production under specifications
controlled by the roll-maker. Earlier grades such as 70Cr3NiMo are still
in use, but are gradually being replaced due to their lower hardening depth
capability. More recent grades include 45Cr4NiMoV and 50Cr5NiMoV,
developed for deeper hardening response and higher strength demands. These
references indicate the material type, but they do not define roll performance.
Grade selection must be based on actual rolling
conditions and performance targets, rather than material reference alone.
Cr-Ni-Mo Forged Backup Rolls represent a material range rather than a fixed grade structure,
defined by a deeper hardening response while maintaining sufficient toughness
and structural reliability under actual rolling conditions.
Compared with standard Cr-Mo BURs,
Cr-Ni-Mo Backup Rolls provide a deeper hardening response through the section.
They are less tolerant, and call for a controlled transition with stricter
requirements across roll-making, mill operation, and roll-shop practice. Cr-Ni-Mo Backup Rolls are not suitable for mills with unstable rolling conditions, poor cooling
control, or inconsistent grinding practice.
Common failure mechanisms include
subsurface fatigue damage, spalling, grinding-induced cracking, and premature
loss of usable service life. They typically result from operating conditions
that do not adequately support the material response.
Cr-Ni-Mo Forged Backup Rolls (CrNiMo BUR) belong to the broader family of forged rolling mill rolls used in steel and non-ferrous rolling mills.
Vulcan Metal provides forged rolling mill rolls, including Cr-Ni-Mo Forged Backup Rolls and other forged roll materials, selected according to actual rolling mill conditions and performance requirements.
For additional information, you can also consult our page on
Forged Rolling Mill Rolls.
In addition, you may refer to our dedicated pages covering the main forged roll material families:
