Low Density Medium Alloyed Steel with Aluminum and Manganese
Solution Overview
Problem
Medium alloyed steels used in industrial and transport sectors face challenges due to high costs and scarcity of alloying elements like Cr, Mo, Ni, and V, which also result in high density and limited hardenability, leading to increased energy consumption and susceptibility to deformations and cracks.
Innovation Solution
Development of low-density medium alloyed steels using abundant manganese and aluminum, avoiding costly elements, with a specific chemical composition and heat treatment process that includes vacuum melting, normalizing, and tempering to enhance mechanical properties and reduce density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If costly alloying elements (Cr, Mo, Ni, V) are used to improve mechanical properties, then strength and hardenability are improved, but production cost and density increase
Solution Approach 1:
The patent changes the chemical composition parameters by replacing scarce alloying elements (Cr, Mo, Ni, V) with abundant elements (Mn, Al, Si) and optimizes their content ranges. Specifically, it uses Mn (1.50-4.00 wt.%), Al (0.50-2.00 wt.%), and Si (0.10-1.00 wt.%) to achieve the desired mechanical properties without relying on expensive elements, thereby resolving the contradiction between strength improvement and cost reduction
Solution Approach 2:
The patent substitutes expensive, scarce alloying elements with cheap, abundant elements. By using Mn, Al, and Si which are readily available and low-cost, the invention replaces the function of costly Cr, Mo, Ni, and V, achieving similar or better mechanical properties at significantly lower material cost
2Strength
If traditional medium alloyed steels are used to achieve mechanical strength, then strength is improved, but density increases leading to higher energy consumption
Solution Approach 1:
The patent modifies the compositional parameters by eliminating dense alloying elements and using lighter alternatives. The specified composition with Mn (1.50-4.00 wt.%), Al (0.50-2.00 wt.%), and Si (0.10-1.00 wt.%) creates a steel alloy with reduced density while maintaining mechanical strength, directly addressing the weight-strength contradiction
3Quantity of substance
If limited hardenability steel is used to reduce alloying, then cost is reduced, but susceptibility to deformations and cracks increases
Solution Approach 1:
The patent optimizes the compositional parameters to achieve adequate hardenability without excessive alloying. The specific ranges of Mn (1.50-4.00 wt.%), Al (0.50-2.00 wt.%), and Si (0.10-1.00 wt.%) are designed to provide sufficient hardenability for the steel to resist deformations and cracks during heat treatment, while keeping the overall alloying content moderate and cost-effective
Solution Approach 2:
The patent uses Al and Si as intermediary elements that enhance the hardenability and mechanical properties of the Mn-based steel system. These elements act as mediators that improve the steel's resistance to deformations and cracks without requiring the addition of expensive alloying elements, thus resolving the contradiction between limited alloying and improved reliability
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 new alloyed steels achieve balanced mechanical properties with reduced density, lower production costs, and improved hardenability, allowing for energy savings and reduced deformation risks, while maintaining or exceeding the performance of traditional alloys like G42CrMo4 and G26CrMo4.
Implementation Method 1
The present invention provides new low density medium alloyed steels; the steels of the present invention comprise aluminium and manganese, which are alloying elements abundant in nature
Implementation Method 2
different conventional quenching and tempering heat treatments were used in their preparation of such steels
Implementation Method 3
in steel making processes, using arc furnaces, ladle furnaces and a vacuum degassing step
Implementation Method 4
The alloys according to the present invention are free of at least one of Cr, Mo, Ni and V, preferably free of Cr, Mo, Ni and V
Implementation Method 5
different conventional quenching and tempering heat treatments were used in their preparation of such steels
Data Source
Figure 1~2
Figure 3~4b
Figure 5a~6b
AI summary
Medium alloyed steels comprising aluminum, manganese, carbon, silicon and iron, with low density and balanced mechanical properties. The alloys may be manufactured by a process including a normalizing and a tempering heat treatment, and machinery parts, such as machine shafts, industrial machines and vehicles cogwheels, spanners, cardan forks, crankshafts, camshafts, steering box forks, body and white components and engine mounts, may be manufactured with said alloys.