Working Roll Deep Rolling for Uniform Hardness and Residual Stress
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Solution Overview
Problem
Rolls used in metal rolling processes face challenges with uneven surface hardness and residual stress, leading to rolling defects and the need for frequent reconditioning and reclassification, especially due to material overlaps during the rolling process.
Innovation Solution
A method involving a pressure tool with a pressure element that rotates relative to the roll, applying localized pressure to set surface hardness through cold work hardening and influence near-surface residual stress, ensuring a uniform and reproducible material property change up to 0.2-0.3 mm depth, combined with a feed motion to condition the roll surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If rolls are used in metal rolling processes, then material deformation is achieved, but surface hardness becomes uneven and rolling defects occur
Solution Approach 1:
The patent applies localized pressure through a pressure tool with a pressure element to specific regions of the roll surface, creating non-uniform pressure distribution that induces cold work hardening only in targeted areas. This local treatment approach allows different regions of the roll to have different hardness characteristics, directly resolving the contradiction by making surface hardness uniform through localized modification rather than treating the entire roll uniformly.
Solution Approach 2:
The patent changes the physical and mechanical parameters of the roll surface by applying controlled pressure that induces cold work hardening. The pressure element modifies the surface hardness and residual stress parameters locally, transforming the roll surface properties to achieve uniform hardness distribution and eliminate rolling defects. This parameter change approach directly addresses the technical contradiction by modifying surface properties to prevent defects.
2Manufacturing precision
If rolls are reground to restore surface quality, then surface roughness is improved, but residual stress changes and rolling errors reoccur
Solution Approach 1:
The patent applies preliminary pressure treatment to the roll surface before it is reground. By inducing cold work hardening and establishing favorable residual stress patterns in advance, the treatment prepares the roll surface to maintain its properties even after regrounding. This preliminary action ensures that when the roll is subsequently reground to restore surface roughness, the residual stress and hardness characteristics are preserved, preventing rolling errors from recurring.
3Force
If working rolls are subjected to high stress during rolling, then material deformation is achieved, but roll damage occurs from material overlaps
Solution Approach 1:
The patent strengthens specific high-stress regions of the roll by applying localized pressure treatment. The pressure element targets areas most susceptible to damage from material overlaps, inducing cold work hardening that increases local strength and hardness. This local quality enhancement allows the roll to withstand high rolling forces without damage, directly resolving the contradiction between applying sufficient force and maintaining roll strength.
Solution Approach 2:
The patent applies preliminary pressure treatment to induce compressive residual stress in the roll surface before the roll is subjected to high stress during rolling operations. This preliminary anti-action creates a protective stress state that counteracts the tensile stresses and impacts from material overlaps, preventing roll damage. The pre-induced compressive stress acts as a counterforce to the damaging forces encountered during rolling.
4Reliability
If rolls are frequently checked and reclassified, then quality control is maintained, but handling complexity increases
Solution Approach 1:
The patent permanently modifies the roll surface parameters through cold work hardening, creating consistent and uniform hardness and residual stress characteristics. This parameter change ensures that treated rolls maintain stable properties throughout their service life, eliminating the need for frequent checking and reclassification. The once-and-for-all treatment simplifies roll handling by ensuring consistent quality without requiring complex monitoring and reclassification procedures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method achieves a homogeneous and process-reliable setting of surface hardness and residual stress, reducing rolling errors and extending the life of rolls by making them suitable for various rolling passes, even after regrinding, while maintaining a smooth surface quality.
Implementation Method 1
pressure is applied locally to the roll by means of at least one pressure tool, comprising at least one pressure element, via the at least one pressure element
Data Source
AI summary
The object of providing a method for conditioning a working roll with which the material properties of a working roll can be set in a process-reliable and uniform manner is achieved by a method in which a roll and at least one pressure tool are rotated relative to each other, in which pressure is applied locally to the roll by means of the at least one pressure tool, comprising at least one pressure element, via the at least one pressure element, and in which a deep rolling process is carried out.