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Technical Article

The selection of support roller material shall be considered with the following factors

（1）The roll body has a large diameter (2300/2100mm), a large length (4900mm), and a high rolling force (max 10000KN). The roll is required to have high fracture resistance, and the roll body and neck have high Strength.

(2) The material of the working layer of the roll has good contact fatigue resistance to prevent small peeling of the roll surface caused by local excessive contact during use, or fatigue cracks under the hardened layer due to contact work hardening, causing peeling.

(3) The roll should have sufficient wear resistance to avoid premature uneven wear during use, that is, the middle of the roll has large wear, the edge wear is small, and the rolling force is concentrated on the edge of the roll, causing the edge to peel off.

At present, the main selection of support rolls for medium and heavy plate rolling mills are forged steel, composite cast steel and combined support rolls with sleeves. The first two are used more frequently. The support rolls of the 5m wide and heavy plate rolling mill can choose Cr2, Cr3, Cr4, Cr5 series composite cast steel support rolls. At present, chromium-molybdenum forged steel is selected for 5m wide and heavy plates.

Its chemical composition: C: 0.7—1.0, Si: Max0.50, Mn: Max1.60, Cr: 0.9—1.60, Mo: 0.3—0.60, S and P not more than 0.025

Roll body hardness: 40-50HSC, roll neck hardness: 37-47HSC, working layer thickness: ≥95mm, basic size: 2300/2110×4900×10930mm.

Typical component range of the composite cast steel support roll：%