Rebuilding of HSM Backup Rolls (M. Engg Project)

By: Material type: TextTextLanguage: English Publication details: Karachi : Institute of Materials Sciences and Research Pakistan Steel, 2001Description: X, 90 p. : illSubject(s): DDC classification:
  • 671.32378242 KAY
Summary: Abstract : At hot strip mills of Pakistan Steel, the roughing and finishing stands are of four-high type having two working rolls and two backup rolls, which reduce undesirable bending of the work rolls and enable the rolls to withstand rolling force for smooth operation. During service, backup rolls are subjected to intense compressive stresses and sub surface yielding occurs if the strength of the roll material is insufficient. In addition to mechanical stress, backup rolls are subjected to wear. Pakistan steels imports HSM backup rolls, but no rebuilding is done here. It is thus required that some attention must be given toward rebuilding of backup rolls. Optimum material selection and method for rebuilding requires a fundamental understanding of the wear mechanisms as well as weld metal microstructure property relationships. Selection of proper rebuilding materials and method, microstructural characterization, mechanical properties, study of the roll wear-mechanisms and determination of the causes of roll wear, are the major areas of the work by which it will be possible that scrap backup rolls can be economically repaired/reclaimed with enhanced life as compared to forged or cast steel rolls with cost not more than 50% of the original cost.
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Abstract :

At hot strip mills of Pakistan Steel, the roughing and finishing stands are of four-high type having two working rolls and two backup rolls, which reduce undesirable bending of the work rolls and enable the rolls to withstand rolling force for smooth operation.

During service, backup rolls are subjected to intense compressive stresses and sub surface yielding occurs if the strength of the roll material is insufficient. In addition to mechanical stress, backup rolls are subjected to wear.

Pakistan steels imports HSM backup rolls, but no rebuilding is done here. It is thus required that some attention must be given toward rebuilding of backup rolls. Optimum material selection and method for rebuilding requires a fundamental understanding of the wear mechanisms as well as weld metal microstructure property relationships.

Selection of proper rebuilding materials and method, microstructural characterization, mechanical properties, study of the roll wear-mechanisms and determination of the causes of roll wear, are the major areas of the work by which it will be possible that scrap backup rolls can be economically repaired/reclaimed with enhanced life as compared to forged or cast steel rolls with cost not more than 50% of the original cost.