High Surface-Pressure Steel Component for Wear Resistance
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Solution Overview
Problem
Conventional high surface-pressure components, such as CVT pulleys, face wear issues due to high frictional contact, and existing solutions like shot-peening treatments are costly and can contaminate the sliding surface, while previous compositions do not adequately enhance wear resistance without additional treatments.
Innovation Solution
A high surface-pressure resistant component made from steel with specific chemical composition (C: 0.17-0.23%, Si: 0.80-1.00%, Mn: 0.65-1.00%, P: 0.030% or less, S: 0.030% or less, Cu: 0.01-1.00%, Ni: 0.01-3.00%, Cr: 0.80-1.00%, Nb: 0.045-0.065%, Al: 0.030-0.047%, N: 0.015-0.030%) is developed, with a carburized and quenched surface layer having a C concentration of 0.70-0.80%, and a manufacturing method involving hot-forging, machining, and controlled carburizing to satisfy the relationship between effective pinning particle amount and ferrite average grain size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shot-peening treatment is applied to improve surface hardness, then wear resistance is improved, but manufacturing cost increases and sliding surface contamination occurs
Solution Approach 1:
The invention changes the chemical composition parameters of the steel material, specifically setting C: 0.17-0.23%, Si: 0.80-1.00%, Cr: 0.80-1.00%, and other elements within specific ranges. This compositional parameter change enables the steel to achieve high surface hardness (650 Hv or more) through carburizing and quenching treatment alone, eliminating the need for additional shot-peening treatment and thus reducing manufacturing cost while avoiding sliding surface contamination.
Solution Approach 2:
The invention extracts and eliminates the shot-peening treatment step from the manufacturing process by incorporating the hardening function directly into the steel material composition and heat treatment process. The specialized steel composition with controlled C, Si, Cr, and other elements achieves the desired surface hardness through carburizing and quenching alone, removing the need for separate shot-peening operations and their associated costs and contamination issues.
2Reliability
If shot-peening treatment is applied to improve surface hardness, then wear resistance is improved, but sliding surface contamination occurs
Solution Approach 1:
The invention changes the chemical composition parameters of the steel material, specifically setting C: 0.17-0.23%, Si: 0.80-1.00%, Cr: 0.80-1.00%, and other elements within specific ranges. This compositional parameter change enables the steel to achieve high surface hardness (650 Hv or more) through carburizing and quenching treatment alone, eliminating the need for additional shot-peening treatment and thus reducing manufacturing cost while avoiding sliding surface contamination.
3Ease of manufacture
If conventional steel composition is used, then manufacturing cost is reduced, but wear resistance under high surface pressure is insufficient
Solution Approach 1:
The invention changes the chemical composition parameters of the steel material, specifically setting C: 0.17-0.23%, Si: 0.80-1.00%, Cr: 0.80-1.00%, and other elements within specific ranges. This compositional parameter change enables the steel to achieve high surface hardness (650 Hv or more) through carburizing and quenching treatment alone, eliminating the need for additional shot-peening treatment and thus reducing manufacturing cost while avoiding sliding surface contamination.
Solution Approach 2:
The invention uses a composite material approach by combining multiple alloying elements (C, Si, Cr, Mn, Cu, Ni, Nb, Al, N) in specific proportions to create a steel composition that achieves superior wear resistance. The synergistic effect of these elements provides high-temperature tempered hardness and prevents grain coarsening, delivering enhanced performance without requiring additional processing steps.
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 component achieves enhanced wear resistance without shot-peening, maintaining a hardness of 650 Hv or more after tempering at 300°C, effectively prolonging the fatigue lifetime of the sliding surface and preventing coarsening of crystal grains during carburizing.
Implementation Method 1
performing a carburizing treatment, in which the method includes controlling component compositions and/or manufacturing conditions of the workpiece so that a relationship between an effective pinning particle amount X during the carburizing and a ferrite average grain size number Y before the carburizing satisfies the following Equation (1)
Implementation Method 2
a surface layer of a carburized and quenched layer has a C concentration of 0.70% to 0.80% by mass %
Implementation Method 3
maintaining a hardness of 650 Hv or more after tempering at 300°C
Implementation Method 4
the effective pinning particle amount X is a value (ppm) obtained by subtracting precipitation amounts of NbC and AlN after the hot-forging treatment from precipitation amounts of NbC and AlN after the carburizing treatment
Data Source
AI summary
A high surface-pressure resistant component includes a steel having a composition containing, in mass %, 0.17-0.23% of C, 0.80-1.00% of Si, 0.65-1.00% of Mn, 0.030% or less of P, 0.030% or less of S, 0.01-1.00% of Cu, 0.01-3.00% of Ni, and 0.80-1.00% of Cr, with the remainder being Fe and unavoidable impurities, in which the surface layer C concentration of a carburized and quenched layer is 0.70-0.80% in mass %.