Influence of steel hardenability on residual stresses in hardening the sleeves of large built-up back-up rolls

Conclusions

• 1. It is recommented that sleeves to be hardened and tempered to reduce residual stresses be produced from steels providing suppression of pearlitic transformations with the quenching method used (steels with specified hardenability). For 1600–2100 mm diameter 230–290 mm thick sleeves of large built-up back-up rolls it is desirable to use a steel with minimum stability of the austenite in the pearlitic area (incubation period 200–220 sec).

• 2. With use of steels with an increased alloy content a decrease in quenching intensity of sleeves in hardening is possible.

• 3. In production of sleeves of steel of a given type it is necessary to determine the maximum possible thickness of sleeves for which through hardenability and the minimum level of residual stresses after hardening are provided. Thicker sleeves must be produced from steels with higher hardenability or be quenched more intensely in hardening.

• 4. In development of heat treat cycles for sleeves of steels with increased hardenability it is necessary to take into consideration the stability of austenite in tempering.