Реферат: Конструкция и усовершенствование технического обслуживания тянущих валков

– application in both top and bottom roll positions (compared with the 4-piece roll which could only be used in top roll positions);

– elimination of inventory for inner and outer certifugally cast sleeves, stub ends, etc, required to construct the 4-piece roll.

– initial cost of high-alloy gun drilled roll is 30% less compared to either the 4-piece or solid grade 8620 rolls.

– maintain roll bearing temperatures at least 250˚F coller than externally cooled solid bottom rolls.

In comparison with the high-alloy gun-drilled roll, the two types of 4-piece rolls represents 80% of the roll failures with only 50% of the cast tonnage.

High reliability has been achieved by adopting a high-alloy, gun-drilled internally water-cooled roll design, special type bearings and a computerized roll tracking system that forms an integral part of a preventive maintenance program.

Adoption of a high-alloy, gun-drilled roll design resulted in an increase in service life from approximately 425,000 cast tons for a 4-piece hollow roll used previously, to more than 1.2 million tons together with a 90% reduction in overall roll failures.

The life of this type bearings is twice as long as that of spherical bearings. In 1988, a bearing failure rate of approximately 36 per million tons cast represents a reduction of 66% over 1981 levels. Additional benefits of this type bearing include a significant reduction in greasing requirements and lower build-up and journal repair costs.

The roll tracking program has led to a reduction in roll inventory, reduced caster downtime and provided a basis for making more efficient roll purchasing decisions as well as establishment of the preventive maintenance program.

Словарь

withdrawal rolls – тянущии валки

bearing seal – роликовая опора качения

withdrawal of section – вытягивание заготовки

high-alloy gun-drilled roll – валок с осевым отверстием из высоколегированного сплава

top roll – верхний валок

bottom roll – нижний валок

4-piece roll – четырёхсоставной валок

4-piece caster roll – четырёхсоставной верхний опорный валок

4-piece hollow roll – четырёхсоставной пустотелый валок

elimination of inventory – сложность инвентаря

stub end -конец без буртика

inner sleeve – внутренний бандаж валка

outer sleeve – внешний бандаж валка

solid caster roll – сплошной верхний опорный валок

gun-drilled caster roll – верхний опорный валок с осевым отверстием

grade 8620 steel – сталь марки 8620

high-alloy – высоколегированный сплав

radiation pyrometer – радиоционный пирометр

finite element analysis – расчёт методом конечных элементов