Composite Cemented Carbide Roll Structure for Dent-Resistant Cold Rolling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing composite cemented carbide rolls face challenges in achieving sufficient compressive yield strength for cold rolling of steel strips, leading to surface dents and high production costs due to complex assembly and limited size constraints, with existing compositions offering inadequate toughness and hardenability.
Innovation Solution
A composite cemented carbide roll design featuring an outer layer of cemented carbide with 55-90% WC particles and 10-45% Fe-based binder phase, metallurgically bonded to an inner layer of iron-based alloy with 2% or more Cr, Ni, or Mo, and a shaft member with low Cr, Ni, and Mo content, optimized for HIP bonding and welding to achieve high compressive yield strength and reduced residual stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cemented carbide is used for rolls to achieve wear resistance and surface roughening resistance, then rolling quality is improved, but the roll structure becomes complex and costly due to metal shaft insertion and complicated assembling
Solution Approach 1:
The invention merges the metal shaft and cemented carbide sleeve into a single integrated roll structure. The roll is constructed as a solid cemented carbide body with a through-hole for the drive key, eliminating the need for separate shaft and sleeve components. This integration simplifies the assembly structure while maintaining the wear resistance and rolling quality benefits of cemented carbide.
2Reliability
If cemented carbide roll is used to achieve excellent wear resistance, then rolling quality is improved, but production cost increases due to expensive material and difficult forming
Solution Approach 1:
The invention changes the compositional parameters of the cemented carbide by incorporating specific amounts of alloying elements (0.5-5.0 mass% Ni, 0.1-3.0 mass% Cr, 0.1-2.0 mass% Mo, 0.03-1.0 mass% V) into the traditional WC-Co system. These parameter changes improve the material's toughness and hardenability, enabling the production of longer rolls without increasing production cost, while maintaining excellent wear resistance.
3Productivity
If long composite cemented carbide rolls are produced to meet demand for rolling wide strips, then productivity is improved, but residual tensile stress in bonding boundary increases leading to roll breakage
Solution Approach 1:
The invention changes the chemical composition parameters of the cemented carbide by adding specific alloying elements that improve toughness and hardenability. This allows the production of longer rolls (over 2000 mm) while maintaining sufficient bonding boundary strength to prevent breakage from residual tensile stress during cold rolling operations.
4Reliability
If existing cemented carbide composition is used to achieve hardness, then wear resistance is improved, but compressive yield strength is insufficient leading to surface dents in cold rolling
Solution Approach 1:
The invention changes the compositional parameters by incorporating Ni (0.5-5.0 mass%), Cr (0.1-3.0 mass%), Mo (0.1-2.0 mass%), and V (0.03-1.0 mass%) into the cemented carbide matrix. These parameter changes enhance the binder phase's hardenability and compressive strength, enabling the roll to withstand cold rolling pressures without surface dents while maintaining wear resistance.
Solution Approach 2:
The invention creates a composite cemented carbide material by combining WC particles with a modified binder phase containing multiple alloying elements. This composite structure provides both the hardness needed for wear resistance and the enhanced compressive yield strength required to prevent surface dents during cold rolling of steel strips.
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
The solution enables continuous high-quality cold rolling with reduced surface dents and allows for the production of long, cost-effective composite cemented carbide rolls with diameters over 200 mm and lengths over 2000 mm, enhancing mechanical strength and reducing production costs.
Implementation Method 1
the binder phase having a structure comprising 50% or more in total by area of bainite phases and/or martensite phases
Implementation Method 2
conduct hot isostatic pressing (HIP)
Data Source
AI summary
A composite cemented carbide roll comprising an inner layer made of an iron-based alloy, and an outer layer made of cemented carbide which is metallurgically bonded to an outer peripheral surface of the inner layer; the cemented carbide of the outer layer comprising 55-90 parts by mass of WC particles and 10-45 parts by mass of an Fe-based binder phase having a particular composition; a shaft member and a shaft end member being metallurgically bonded to at least one axial end of the inner layer; the inner layer being made of an iron-based alloy containing 2.0% or more in total by mass of at least one selected from the group consisting of Cr, Ni and Mo; and the shaft member and the shaft end member being made of an iron-based alloy containing 1.5% or less in total by mass of at least one selected from the group consisting of Cr, Ni and Mo.