Acicular softer grades have bainitic matrix, and hardest grades have bainitic-martensitic microstructure. Compared with pearlitic rolls, these rolls are higher alloyed and can reach a higher hardness. We can influence the hardness of acicular rolls by the graphite and carbide contents which we determine by chemical composition and melt inoculation. The intended bainitic – martensitic microstructure is obtained by different tempering processes too.

Because of their lower thermal conductivity and toughness, acicular rolls have a lower resistance against fire cracking compared to pearlitic rolls. Acicular rolls are stronger and more wear resistant compared to pearlitic rolls of the same hardness. The wear resistance increases with the increasing hardness. Heat treatment improves the resistance to fire cracking.

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AcH70CN-Acicular Matrix with Carbides and

Nodular Graphite(x500)

AcH62N-Bainitic Matrix with Carbides and

Nodular Graphite(x100)

Roll Grade Barrels Hardness (ShC) C (%) Si (%) Mn (%) Cr (%) Ni (%) Mo (%) Tensile Strength (N/mm2) Bending Strength (N/mm2)
Ac 42N 42 3.2-3.6 1.2-2.2 0.1-0.4 0-0.3 2.2-3.5 0.2-0.8 500-800 1100-1300
Ac 46N 46 3.2-3.6 1.2-2.2 0.1-0.4 0-0.3 2.2-3.5 0.2-0.8 500-800 1100-1300
Ac 50N 50 3.2-3.6 1.2-2.2 0.1-0.4 0.2-0.5 2.2-3.5 0.2-0.8 400-500 1100-1300
Ac H 54  N 54 3.2-3.6 1.2-2.0 0.1-0.4 0.2-0.8 2.4-3.8 0.2-0.8 400-500 1100-1300
Ac H 58 N 58 3.2-3.6 1.1-1.8 0.2-0.6 0.2-0.8 2.4-3.8 0.2-0.8 400-500 900-1100
Ac H 62 N 62 3.2-3.6 1.1-1.8 0.2-0.6 0.2-0.8 2.6-4.2 0.2-1 400-500 900-1100
Ac H 66 N 66 3.2-3.6 1.1-1.8 0.2-0.8 0.3-1.0 2.6-4.2 0.2-1 400-500 900-1100
Ac H 68 N 68 3.2-3.6 1.1-1.8 0.2-0.8 0.3-1.0 2.6-4.2 0.2-1 300-450 750-950
Ac H 70 N 70 3.2-3.6 1.0-1.8 0.2-0.8 0.4-1.2 0.4-1.2 0.2-1 300-450 750-950
Ac H 72 N 72 3.2-3.6 1.0-1.8 0.2-0.8 0.4-1.2 2.6-4.2 0.2-1 300-450 750-950
Ac H 60 CN 60 3.2-3.6 1.0-1.8 0.2-0.7 0.3-0.9 2.6-4.2 0.2-1 See core Material Info in link1
Ac H 62 CN 62 3.2-3.6 1.0-1.8 0.2-0.7 0.3-0.9 2.6-4.2 0.2-1 See core Material Info in link1
Ac H 64 CN 64 3.2-3.6 1.0-1.8 0.2-0.7 0.3-0.9 2.6-4.2 0.2-1 See core Material Info in link1
Ac H 66 CN 66 3.2-3.6 1.0-1.8 0.2-0.7 0.3-0.9 2.6-4.2 0.2-1 See core Material Info in link1
Ac H 68 CN 68 3.2-3.6 1.0-1.8 0.2-0.7 0.3-0.9 2.6-4.2 0.2-1 See core Material Info in link1
Ac H 70 CN 70 3.2-3.6 1.0-1.8 0.2-0.7 0.3-0.9 2.6-4.2 0.2-1 See core Material Info in link1
Ac H 72 CN 72 3.2-3.6 1.0-1.8 0.2-0.7 0.3-1.1 2.6-4.2 0.2-1 See core Material Info in link1
Ac H 74 CN 74 3.2-3.6 1.0-1.8 0.2-0.7 0.3-1.1 2.6-4.2 0.2-1 See core Material Info in link1
Ac H 76 CN 76 3.2-3.6 1.0-1.8 0.2-0.7 0.4-1.2 2.6-4.2 0.2-1 See core Material Info in link1

Note: On request, other roll grades not specified in the table can be produced. Cores for compound rolls can be produced with Grey, Compact or Nodular cast iron.