Cold-Rolled Steel Plate Heat Spot Resistance
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Solution Overview
Problem
Existing methods for enhancing heat spot resistance and antiwear performance in clutch plates fail to adequately address all defect phenomena, particularly heat spots, and often increase material costs or compromise efficiency, size, and weight reduction.
Innovation Solution
A cold-rolled steel plate with a specific chemical composition and microstructure, including Ti-based carbides, is developed to enhance heat conductivity, suppress austenitization, and maintain strength and antiwear performance, featuring a composition of C, Si, Mn, P, S, Ti, Al, and optional Cr, Ni, Mo, B, Nb, and V, with Ti-based carbides dispersed uniformly to control heat spot formation and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the diameter of the clutch plate is reduced to enhance efficiency, then the efficiency of the multiplate wet clutch is improved, but the temperature increase becomes excessive causing heat spots that cannot be handled with conventional techniques
Solution Approach 1:
The invention changes the chemical composition parameters of the steel plate by precisely controlling the content ranges of C (0.15-0.35%), Si (0.01-1.50%), Mn (0.10-1.00%), Ti (0.01-0.50%), and other elements. This compositional parameter adjustment modifies the material's thermal properties and phase transformation characteristics, enabling the plate to resist heat spot formation even when reduced in size and subjected to higher temperatures from frictional heating.
2Use of energy by moving object
If the number of clutch plates is reduced to enhance efficiency, then the efficiency of the multiplate wet clutch is improved, but the temperature increase becomes excessive causing heat spots that cannot be handled with conventional techniques
Solution Approach 1:
The invention adjusts the chemical composition parameters of the steel plate, specifically controlling C (0.15-0.35%), Si (0.01-1.50%), Mn (0.10-1.00%), Ti (0.01-0.50%), and other elements within specified ranges. These parameter changes modify the material's thermal response and phase transformation behavior, enabling the clutch to operate with fewer plates while resisting heat spot formation despite increased thermal loading.
3Use of energy by moving object
If the coefficient of friction is increased by reducing lubricant and changing friction material to enhance efficiency, then the efficiency of the multiplate wet clutch is improved, but the temperature increase becomes excessive causing heat spots that cannot be handled with conventional techniques
Solution Approach 1:
The invention modifies the chemical composition parameters of the steel plate by controlling C (0.15-0.35%), Si (0.01-1.50%), Mn (0.10-1.00%), Ti (0.01-0.50%), and other elements. These parameter adjustments enable the base material to better withstand the increased frictional heating that results from higher coefficient of friction operations, preventing heat spot formation even when lubricant is reduced and friction material is changed to achieve higher efficiency.
4Reliability
If low-carbon steel is used to increase the temperature of phase transformation from ferrite to austenite, then the occurrence of phase transformation is prevented during clutch engagement, but the heat spot resistance is not sufficient
Solution Approach 1:
The invention creates a composite chemical composition system that combines low-carbon steel (C: 0.15-0.35%) with specific amounts of Si (0.01-1.50%), Mn (0.10-1.00%), Ti (0.01-0.50%), and other alloying elements. This composite material approach prevents austenite formation during frictional heating while Ti and other elements provide precipitation hardening to maintain sufficient material strength, resolving the contradiction between heat spot resistance and strength.
Solution Approach 2:
The invention optimizes the chemical composition parameters by controlling C (0.15-0.35%), Si (0.01-1.50%), Mn (0.10-1.00%), Ti (0.01-0.50%), and other elements within specific ranges. This parameter optimization ensures that the steel remains ferritic during clutch engagement to prevent heat spots, while the combined effect of multiple alloying elements maintains the necessary material strength for clutch plate application.
5Reliability
If the thermal diffusivity is increased by defining alloy element content, then the temperature increase of the plate is suppressed, but the heat spot resistance is not sufficient
Solution Approach 1:
The invention develops a composite steel composition combining multiple alloying elements: C (0.15-0.35%), Si (0.01-1.50%), Mn (0.10-1.00%), Ti (0.01-0.50%), and optional Cr, Ni, Mo, B, Nb, V. This composite material approach suppresses temperature increase through controlled thermal diffusivity while simultaneously preventing austenite formation and providing precipitation hardening, achieving comprehensive heat spot resistance that single-element additions cannot provide.
Solution Approach 2:
The invention adjusts the chemical composition parameters by controlling the content ranges of multiple elements: C (0.15-0.35%), Si (0.01-1.50%), Mn (0.10-1.00%), Ti (0.01-0.50%), and others. These parameter changes collectively suppress temperature increase, prevent phase transformation, and maintain strength, providing sufficient heat spot resistance that cannot be achieved by defining alloy element content for a single property alone.
6Reliability
If austenitic stainless steel is used to prevent phase transformation, then the occurrence of heat spots is suppressed, but the material cost increases significantly
Solution Approach 1:
The invention replaces expensive austenitic stainless steel with a more economical low-carbon steel composition (C: 0.15-0.35%) that achieves heat spot resistance through controlled ferritic structure and precipitation hardening from Ti and other alloying elements. This substitution maintains the necessary heat spot resistance while significantly reducing material cost, making the clutch plate more economically viable without sacrificing performance.
Solution Approach 2:
The invention creates a cost-effective composite steel composition combining low-carbon steel with specific amounts of Si, Mn, Ti, and other alloying elements. This composite material provides heat spot resistance comparable to austenitic stainless steel but at a fraction of the cost, by preventing austenite formation through controlled chemistry and providing strength through precipitation hardening, thereby resolving the contradiction between heat spot resistance and material cost.
7Reliability
If Ti precipitate or Nb precipitate is used to suppress heat spot occurrence, then the heat spot resistance is improved, but the antiwear performance of the spline part is not sufficient
Solution Approach 1:
The invention applies local quality by controlling the distribution and size of Ti-based carbide precipitates (average diameter 20-100 nm) within the steel matrix. These fine, uniformly distributed precipitates provide precipitation hardening that enhances both heat spot resistance and antiwear performance of the spline part. The local refinement of microstructure through controlled precipitate formation simultaneously improves thermal and mechanical properties, resolving the contradiction between heat spot resistance and wear resistance.
Solution Approach 2:
The invention develops a composite steel composition containing Ti (0.01-0.50%) and optional Nb, combined with C, Si, Mn, and other elements. The Ti-based carbide precipitates formed from this composite chemistry provide dual functionality: suppressing heat spot occurrence through controlled phase transformation and enhancing antiwear performance through precipitation hardening. This composite material approach simultaneously achieves both heat spot resistance and sufficient spline part wear resistance.
8Reliability
If the content of alloying elements is increased to enhance heat spot resistance, then the heat spot resistance is improved, but the material cost increases
Solution Approach 1:
The invention optimizes the chemical composition parameters by controlling the content ranges of multiple alloying elements: C (0.15-0.35%), Si (0.01-1.50%), Mn (0.10-1.00%), Ti (0.01-0.50%), and others. This parameter optimization achieves heat spot resistance through the synergistic effect of controlled ferritic structure and precipitation hardening, without requiring excessive alloying element content. The balanced composition provides necessary performance while controlling material cost, resolving the contradiction between heat spot resistance and manufacturing cost.
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 effectively suppresses heat spot formation and enhances antiwear performance, achieving balanced heat spot resistance and antiwear characteristics while maintaining material strength and reducing material costs, thus improving clutch efficiency and durability.
Implementation Method 1
enhance heat conductivity, suppress austenitization, and maintain strength and antiwear performance
Implementation Method 2
suppress austenitization
Implementation Method 3
frictional heat rapidly enters a surface of the separator plate to become a sliding portion, thereby increasing the temperature of the surface of the separator plate
Data Source
AI summary
A cold-rolled steel plate having favorable heat spot resistance and favorable antiwear performance is provided.The cold-rolled steel plate has a chemical composition containing C from 0.03 to 0.12%, Si from 0 to 1.0% (including a case where Si is not added), Mn from 0.2 to 0.8%, P at 0.03% or less (excluding a case where P is not added), S at 0.03% or less (excluding a case where S is not added), Ti from 0.04 to 0.3%, and Al at 0.05% or less (excluding a case where Al is not added). A residue is formed of Fe and unavoidable impurities. Each element satisfies a relationship of 5*C %−Si %+Mn %−1.5*Al %<1 within the aforementioned range of the corresponding content. An average diameter of particles of a Ti-based carbide is from 20 to 100 nm. In this way, the Ti-based carbide is dispersed finely and uniformly, thereby enhancing heat spot resistance and antiwear performance.