Continuous casting roll

Through examination of roll surfaces, throughout the life cycle of clad rolls, revealed that the mechanism of crack initiation is usually the result of the presence of corrosion pits and crevices, particularly in the reheated/overlap zones of weld beads. these areas are sensitized by the welding thermal cycle, and are prone to Cr depletion and corrosion.

Kinds of defects for continuous casting roll
- Stress corrosion cracking
- Pitting
- Thermal and thermomechanical fatigue
- Severe stress corrosion cracking
- High compressive stress
- Surface roughness

Our 400N series for open arc welding alloys has been developed to overcome the conventional problems associated with the ferritic/martensitic alloys which have limited corrosion resistance, particularly in the area of bead overlap, caused by chromium carbide precipitation. The solution presented consists of a substitution of carbon for nitrogen to ensure that no areas depleted of chrome arise. Evidence of carbide formation, in high carbon materials, caused by re-heating weld deposits and the consequential pitting corrosion and preferential cracking is presented.
Rolls used in steel continuous casting lines have been found to display extended life expectancy if clad, by welding, with a surface simultaneously resistant to the contact with hot slab and the harsh environment within a caster. Over the years that casters have been in operation, a number of roll surfaces for this application have been tried, and more recently industry world-wide has standardized around a 400N series 12% Cr alloy.


400N series of Welding Alloy for continuous casting line

- Maximum tempering resistance (roll surface reaches 600°C)
- Resistance to thermal and thermodynamically fatigue
- High thermal conductivity
- Low thermal expansion
- High temperature oxidation resistance
- Resistance to pitting and corrosion
- Maximum resistance to stress corrosion cracking and
corrosion fatigue
- Good weldability
- Easy machineability
- M f temperature above room temperature
- No post-weld heat treatment
- Reasonably cheap
- High hardness, good abrasion and adhesion resistance