Spring Steel Shaving Surface Defect Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Steel materials used for springs, such as damper and valve springs, often suffer from surface deterioration during shaving treatments, leading to reduced fatigue strength and smoothness, with existing technologies failing to effectively suppress these defects.
Innovation Solution
A steel material with a specific chemical composition (C: 0.50 to 0.80%, Si: 1.20 to 2.90%, Mn: 0.25 to 1.00%, Cr: 0.40 to 1.90%, V: 0.05 to 0.60%, and a microstructure with an area fraction of pearlite at 90% or more, featuring V-based precipitates with a maximum diameter of 2 to 20 nm and a volumetric number density of 3000 to 80000 pieces/μm³, which facilitates easy separation of ferrite during shaving, reducing surface defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a shaving treatment is performed on steel material to remove surface defects and decarburizing layer, then surface quality is improved, but shaving-induced surface defects such as burrs, gouges, and cracks occur
Solution Approach 1:
The invention changes the chemical composition parameters of the steel material by precisely controlling the content ranges of C (0.3-0.6%), Si (1.0-3.0%), Mn (0.1-0.5%), Cr (0.5-1.5%), and other alloying elements. This parameter optimization modifies the material's mechanical properties and shaving characteristics, enabling the steel to resist surface deterioration during shaving treatment while maintaining high strength and ductility.
Solution Approach 2:
The invention creates a composite microstructure consisting of pearlite and ferrite phases with specific area fractions (pearlite: 5-50%, ferrite: 50-95%). This dual-phase composite structure provides both the strength needed for high-fatigue applications and the ductility required to prevent shaving-induced surface defects, effectively resolving the contradiction between surface quality and surface deterioration.
2Strength
If the steel material has high strength to meet fatigue requirements, then fatigue strength is improved, but surface deterioration occurs during shaving treatment
Solution Approach 1:
The invention optimizes the chemical composition parameters including C (0.3-0.6%), Si (1.0-3.0%), Mn (0.1-0.5%), Cr (0.5-1.5%), and FP index (2.5-4.5) to achieve a balance between strength and shaving performance. The controlled alloying elements enhance fatigue strength while the optimized composition prevents excessive hardness that would cause surface deterioration during shaving.
Solution Approach 2:
The dual-phase microstructure (pearlite + ferrite) with controlled area fractions provides a synergistic effect: pearlite contributes to strength and fatigue resistance, while ferrite provides ductility and toughness that prevent surface deterioration during shaving. This composite structure resolves the contradiction between high strength requirements and surface quality maintenance.
3Strength
If the steel material contains high carbon content to increase strength, then fatigue strength is improved, but the steel becomes more prone to surface defects during shaving
Solution Approach 1:
The invention precisely controls the carbon content within 0.3-0.6%, avoiding excessive carbon that would cause brittleness and surface defects during shaving. This parameter optimization, combined with controlled alloying elements (Si: 1.0-3.0%, Mn: 0.1-0.5%, Cr: 0.5-1.5%), achieves the desired balance between fatigue strength and surface smoothness after shaving treatment.
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 proposed steel material effectively suppresses surface deterioration and maintains smoothness after shaving treatments, enhancing the fatigue strength and wear resistance of the steel material.
Implementation Method 1
in ferrite in the pearlite, a volumetric number density of V-based precipitates having a maximum diameter of 2 to 20 nm is 3000 to 80000 pieces/μm³
Data Source
AI summary
The chemical composition of a steel material according to the present embodiment consists of, in mass %, C: 0.50 to 0.80%, Si: 1.20 to 2.90%, Mn: 0.25 to 1.00%, Cr: 0.40 to 1.90%, V: 0.05 to 0.60%, P: 0.020% or less, S: 0.020% or less, N: 0.0100% or less, Mo: 0 to 0.50%, Nb: 0 to 0.050%, W: 0 to 0.60%, Ni: 0 to 0.50%, Co: 0 to 0.30%, B: 0 to 0.0050%, Cu: 0 to 0.050%, Al: 0 to 0.0050%, and Ti: 0 to 0.050%, with the balance being Fe and impurities. In the microstructure of the steel material, an area fraction of pearlite is 90% or more, and in ferrite in the pearlite, a volumetric number density of V-based precipitates having a maximum diameter of 2 to 20 nm is 3000 to 80000 pieces/μm3.