Briquette Roller Two-Layer Structure Abrasion Spalling Resistance
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Solution Overview
Problem
Conventional briquetting rolls with single-layer structures of high-speed tool steel or high-chromium cast iron lack sufficient abrasion and spalling resistance, leading to premature degradation and increased manufacturing costs due to limitations in cooling rates and carbide element addition during centrifugal or static casting, and complex manufacturing processes.
Innovation Solution
A two-layer briquetting roll structure featuring a chromium-molybdenum forged steel inner layer and a high-carbon high-speed steel outer layer, formed through a continuous pouring process, providing enhanced mechanical properties and resistance via a metallurgical bond, with homogenization heat treatment and nitrogen cooling in a vacuum furnace to improve toughness and prevent surface deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single-layer structure of high-speed tool steel or high-chromium cast iron is used for the sleeve, then the hardness and abrasion resistance are improved, but the fracture toughness and spalling resistance deteriorate
Solution Approach 1:
The patent applies composite materials by constructing the sleeve with a two-layer structure: an inner layer of chromium-molybdenum forged steel providing toughness and spalling resistance, and an outer layer of high-carbon high-speed steel providing hardness and abrasion resistance. This composite structure resolves the contradiction by combining materials with complementary properties rather than relying on a single material to provide both extremes.
Solution Approach 2:
The patent implements local quality by assigning different material properties to different regions of the sleeve. The inner layer near the shaft center uses tougher chromium-molybdenum forged steel to resist spalling from impact forces, while the outer layer in contact with ironmaking dust uses harder high-carbon high-speed steel to resist abrasion. Each region's material properties are optimized for its specific functional requirements.
2Ease of manufacture
If centrifugal casting or ordinary static casting is used to manufacture the sleeve, then the manufacturing process is simplified, but the cooling rate is limited and segregation of carbide-forming elements occurs, reducing abrasion resistance
Solution Approach 1:
The patent applies parameter changes by fundamentally altering the manufacturing process from casting to continuous pouring. This process change enables precise control of cooling rates and solidification parameters, preventing segregation of carbide-forming elements like V, Mo, and W. The continuous pouring process allows these elements to be distributed uniformly throughout the high-carbon high-speed steel outer layer, achieving the desired abrasion resistance that was unattainable with conventional casting methods.
3Strength
If heat treatment is performed to increase hardness, then abrasion resistance is improved, but the material becomes difficult to machine, requiring electric discharge machining which increases time and cost
Solution Approach 1:
The patent applies preliminary action by performing all mechanical machining operations on the pockets before the final heat treatment that increases hardness to HS 89. The continuous pouring process enables the outer layer to be machined in a softer state using conventional methods, and only after machining is complete is the heat treatment applied to achieve the final hard surface. This sequence reverses the conventional approach of heat treating first, thereby avoiding the need for expensive electric discharge machining.
4Strength
If the entire sleeve is made from high-hardness material to resist abrasion, then abrasion resistance is improved, but spalling occurs due to low toughness, causing the entire unit to become unusable
Solution Approach 1:
The patent resolves this contradiction through composite materials, creating a two-layer sleeve where the inner layer of chromium-molybdenum forged steel provides the toughness necessary to resist spalling, while the outer layer of high-carbon high-speed steel provides the hardness for abrasion resistance. This eliminates the need to choose between hardness and toughness in a single material.
Solution Approach 2:
The patent applies segmentation by dividing the sleeve into functionally distinct layers. The inner layer handles tensile and impact stresses that cause spalling, while the outer layer handles abrasive wear from ironmaking dust. This functional segmentation allows each layer to be optimized for its specific failure mode without compromising the other.
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 two-layer structure offers improved abrasion and spalling resistance, extending the service life and reducing manufacturing time and costs, while allowing for efficient mechanical machining and heat treatment, facilitating easier maintenance and repair by replacing only affected segments.
Implementation Method 1
formed through a continuous pouring process, providing enhanced mechanical properties and resistance via a metallurgical bond
Implementation Method 2
with homogenization heat treatment and nitrogen cooling in a vacuum furnace to improve toughness and prevent surface deformation
Implementation Method 3
with homogenization heat treatment and nitrogen cooling in a vacuum furnace to improve toughness and prevent surface deformation
Implementation Method 4
The two-layer structure offers improved abrasion and spalling resistance
Implementation Method 5
The two-layer structure offers improved abrasion and spalling resistance
Data Source
Figure 1A~2
Figure 3A~3F
Figure 4
AI summary
[Problem to Be Solved] To provide a novel briquetting roll having excellent performance such as providing both abrasion resistance and spalling resistance, which can also be manufactured at low cost and in a short period of time, and a method for manufacturing the same. [Means for Solving the Problem] A briquetting roll 1 integrally has an inner layer material 4 and an outer layer material 5, which comprise mutually different materials and are in contact with each other at the respective exterior and interior thereof, and has pockets 6 formed at the outer circumference of the outer layer material 5. A chromium-molybdenum forged steel material is used for the inner layer material 4 and a high-carbon high-speed steel material is used for the outer layer material 5. The outer layer material 5 may be formed on the outside of the inner layer material 4 by a continuous pouring process.