Overview of forged roll materials and their heat treatment

Rolls are different from general structural components, working conditions are complex and varied, rolling process roll body to withstand high stress, mainly bending stress and friction, etc., the main drive rolls also have to withstand a huge torque. The surface of the roll body should be subjected to friction, wear and tear, impact, contact stress and fatigue phenomenon caused by heat and cold for a long time. Therefore, in addition to the conventional mechanical properties, a variety of rolling mills on the use of roll performance put forward a series of special requirements different from other products.

1. Fracture resistance. Roll body and roll neck to withstand the working stress without transverse fracture ability. For specific conditions of use, mainly should have sufficient strength and toughness, and there is no manufacturing defects that may lead to fracture.
2. Wear resistance. Roller body working parts in the rolling process to resist weight loss or size reduction ability. It should be noted that the rolls in the hot state of wear resistance and wear resistance in the cold state is not necessarily equivalent. A roll in the cold state using the relative wear resistance is not equal to the relative wear resistance in the hot state or vice versa. Work roll wear mechanism are a variety of types of coexistence, rolling friction, rolling material plastic change caused by sliding friction and oxide skin abrasive wear.
3. Spalling resistance. Rolls in the contact stress for a long time without the ability to produce the phenomenon of the roll body off the block.

4. Resistance to thermal cracking. Hot rolling with the work rolls from the rolling material and coolant cooling and thermal fatigue produced by the role of thermal fatigue, resistance to this effect without producing net cracking or make the net crack refinement shallow ability.
5. Thermal shock resistance. Work roll in the bite into the hot billet roll surface local rapid heating or meet the card steel and other accidents due to friction so that the roll surface intense heating, resistance to this thermal shock and does not produce cracks and flaking ability is called thermal shock resistance, is an important measure of the performance of the work rollers.
In addition, there is resistance to roughness, bite into the sex. For a specific mill specific rolls, its performance requirements will focus on, and sometimes require a combination of several properties.

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