One stop service for steel industry

Causes of mill rolls breakage

1: Brittle fracture
The fracture shape of this type of roll is relatively flat, and the surface of the roll body around the fracture is relatively neat;

2: Ductile fracture
The fracture shape of such rolls is mostly “mushroom head”, and the roll body near the fracture is crushed. Comparing the two, it is found that the form of roll breakage in this roll breaking accident is ductile fracture.

Both brittle and ductile fractures are caused by roll stress exceeding core strength. The reasons for this are related to the residual stress of the roll itself, the mechanical stress during rolling and the thermal stress of the roll, especially when the temperature difference between the surface and the core of the roll body is large.
This temperature difference can be caused by poor roll cooling, interruptions in cooling, or overheating of the roll surface at the start of a new rolling cycle. This huge temperature difference between the surface and the core of the roll causes large thermal stress, and when the large thermal stress, mechanical stress and residual stress of the roll exceeds the core strength of the roll, it causes the roll to break. For example, when the temperature difference between the surface of the roll and the core is 70°C, the roll will increase the longitudinal thermal stress of 100MPa. The greater the temperature difference, the greater the increased thermal stress. Compared with rolls with brittle fractures, the core material of rolls with ductile fractures has better toughness and is less prone to fracture. There are four types of stresses that cause roll failure:

  1. Residual stress in the manufacturing process;
  2. Mechanical stress during rolling;
  3. The tissue stress of the roll during the rolling process;
  4. Thermal stress caused by the temperature difference between the inside and outside of the roll.

rolling-mill rolls
Facebook
Twitter
LinkedIn
Reddit

As professional one-stop solution provider, LIAONING MINERAL & METALLURGY GROUP CO., LTD(LMM GROUP) Established in 2007, and focus on engineering research & design, production & delivery, technology transfer, installation & commissioning, construction & building, operation & management for iron, steel & metallurgical industries globally. 

Our product  have been supplied to world’s top steel manufacturer Arcelormittal, TATA Steel, EZZ steel etc. We do OEM for Concast and Danieli for a long time.

LMM Main product series

Core technology products:

  • magnesia carbon brick
  • slide gate plate
  • graphite electrode

Core technology products:

  • Hss roller
  • cast steel rolls
  • tungten carbide ring roller

Core technology products:

  • copper mould tube
  • copper mould plate
  • assembly & cooling jackts

Need For Some Help ?

Professional engineers provide solutions and technical drawings

phone

86(411) 84174804

mail

lmme-business@lmmgroup.com.cn

Special product design, please send specific data and drawings to our mailbox or form.

Get A Free Consultation
And Estimate