Low-Alloy Disc Spring Composition for Strength Without Embrittlement
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Solution Overview
Problem
Existing flat form springs face a trade-off between strength and toughness, where increased strength leads to higher load capacity but also reduces service life due to embrittlement in conventional factory processes.
Innovation Solution
A flat form spring made of low-alloy steel with specific proportions of manganese, chromium, vanadium, molybdenum, and nickel, combined with residual compressive stresses introduced through shot peening or deep rolling, to enhance strength without compromising toughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the strength of flat form springs is increased through conventional quenching and tempering processes, then the load capacity is improved, but the service life is reduced due to embrittlement
Solution Approach 1:
The patent applies parameter changes by precisely controlling the chemical composition parameters of the steel (carbon content 0.35-0.75%, manganese 0.3-0.9%, chromium 0.3-1.5%, molybdenum 0.1-0.6%, nickel 0.4-8%) to achieve optimal balance between strength and toughness. This compositional parameter optimization enables the steel to attain high strength (up to 2100 MPa) while maintaining adequate toughness and service life, resolving the contradiction between load capacity and reliability.
2Strength
If higher strength steel is used to increase load capacity, then the spring can bear greater loads, but the embrittlement from conventional factory processes reduces dynamic service life
Solution Approach 1:
The patent employs composite material principles by creating a low-alloy steel composition that integrates multiple alloying elements (carbon, manganese, chromium, molybdenum, nickel) in specific proportions. This composite steel structure combines the beneficial effects of each element: carbon provides strength, manganese enhances hardenability, chromium improves corrosion resistance, molybdenum increases high-temperature strength, and nickel enhances toughness. The synergistic combination allows the material to achieve high load capacity while maintaining dynamic service life through improved ductility and resistance to embrittlement.
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 significantly improves fatigue strength, service life, relaxation resistance, and load-bearing capacity, enabling the production of flat springs with a strength of up to 2100 MPa while maintaining toughness.
Implementation Method 1
In the flat form spring according to an aspect of the disclosure, its spring properties can be positively influenced by introducing suitable residual compressive stresses by shot peening, smooth rolling, or deep rolling.
Implementation Method 2
the springs can be quenched and tempered with greater strength
Implementation Method 3
After the forming process, the springs are tempered to produce the desired spring elastic properties.
Data Source
AI summary
A flat form spring, in particular a disc spring or corrugated spring, includes a spring body made of a low-alloy steel which has a carbon content of more than 0.35% by weight and at most 0.75% by weight. The steel contains between 0.3 wt. % and 0.9 wt. % manganese (Mn) as an alloying element. The steel also contains chromium (Cr) as an alloying element with a weight proportion of between 0.3 wt. % and 1.5 wt. %. The steel further contains between 0.1% and 0.6% by weight of molybdenum (Mo) as an alloying element. In addition, the steel contains more than 0.4 wt. % and up to 8 wt. % nickel (Ni) as an alloying element. A flatform spring made in this way has an improved strength compared to conventional flatform springs without a loss of toughness compared to a spring made of conventional spring steels.