Alloy-Steel Bearing Raceway Coating for Hardness Without Cracking
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Solution Overview
Problem
Existing bearing components made of steel suffer from limited surface hardness enhancement methods, leading to issues like brittleness and increased risk of crack formation due to hydrogen embrittlement, while conventional methods are costly and inefficient in achieving desired mechanical properties.
Innovation Solution
A bearing component with a metallic base body, such as non-alloyed steel or cast iron, is coated with an alloy steel containing carbide-forming transition metals like niobium, tantalum, or zirconium, using deposition welding to create a high-density, finely distributed carbides, carbonitrides, or nitrides, enhancing surface hardness and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the surface of a steel component is hardened by conventional methods (case hardening, carbonitriding, inductive hardening), then surface hardness is improved, but the edge layer becomes more brittle and prone to crack formation
Solution Approach 1:
The patent changes the chemical composition parameters of the surface layer by introducing specific alloying elements (boron, titanium, niobium, vanadium, zirconium) in controlled amounts. This creates a surface layer with optimized chemical properties that achieves high hardness while maintaining ductility and resistance to hydrogen embrittlement, resolving the contradiction between hardness and brittleness
Solution Approach 2:
The patent creates a composite structure with a base steel material and a surface layer with different chemical composition and properties. The surface layer acts as a protective composite that provides hardness and wear resistance while the specific alloying elements prevent hydrogen embrittlement, thus reducing crack formation risk while maintaining surface strength
2Strength
If alloying elements are added to improve surface properties, then mechanical properties are enhanced, but manufacturing cost increases
Solution Approach 1:
The patent optimizes the concentration ranges of alloying elements to achieve the desired surface properties at minimal effective doses. By precisely controlling the amounts of boron (0.0005-0.005 wt%), titanium (0.01-0.1 wt%), niobium (0.01-0.1 wt%), vanadium (0.01-0.1 wt%), and zirconium (0.01-0.1 wt%), the patent achieves high surface hardness and improved mechanical properties while minimizing material costs associated with expensive alloying elements
3Strength
If the base body is made from high-performance bearing steel, then mechanical properties are improved, but manufacturing cost increases significantly
Solution Approach 1:
The patent applies local quality enhancement by creating a surface layer with specific alloying elements only where needed (in the surface region), while the base body can be made from more cost-effective steel. This localized treatment provides the high-performance properties at the surface where they are most needed, while using economical materials for the bulk material, thus reducing overall manufacturing cost while maintaining mechanical properties
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 method provides a cost-effective solution with improved surface hardness, reduced hydrogen embrittlement, and extended service life by uniformly distributing small carbide particles, thereby enhancing mechanical properties and wear resistance.
Implementation Method 1
The coating is applied onto the base body by deposition welding (cladding)
Implementation Method 2
high-density, finely distributed carbides, carbonitrides, or nitrides
Data Source
AI summary
A bearing component such as a bearing ring includes a metallic base body and at least one alloy steel coating on the base body, the coating being applied to the base body by deposition welding. The base body is preferably non-alloy steel or cast iron, and the alloy includes at least one carbide-forming transition metal such as niobium, tantalum, zirconium, titanium, hafnium, tungsten, molybdenum, vanadium, or manganese. The coating can form a raceway of the bearing component or a structural element such as a flange. Also a method of forming such a bearing component is provided.