Lean Alloy Steel Roll Shells for Molten Aluminum Casting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional steel alloys used in casting roll shells for molten aluminum suffer from thermal fatigue, leading to surface cracks (heat checks) that reduce service life and production efficiency, as increasing elevated temperature yield strength often compromises thermal conductivity.
Innovation Solution
A lean alloy steel composition with specific ranges of elements like carbon, chromium, molybdenum, vanadium, manganese, nickel, phosphorus, sulfur, silicon, and niobium, which provides high elevated temperature yield strength and thermal conductivity, reducing heat checking and enhancing casting speed and service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If selected alloying elements are added to increase elevated temperature yield strength, then the roll shell can resist thermal fatigue better, but thermal conductivity decreases which reduces production yield
Solution Approach 1:
The patent optimizes the concentration ranges of alloying elements (C: 0.20-0.60%, Cr: 0.80-1.50%, Mo: 0.80-1.50%, V: 0.15-0.60%, Mn: 0.20-0.60%, Ni: 0.30-0.70%) to achieve a balance between elevated temperature yield strength and thermal conductivity. This parameter optimization allows the steel to maintain high strength at operating temperatures while preserving sufficient thermal conductivity for production efficiency
Solution Approach 2:
The patent creates a composite alloy system combining multiple elements (C, Cr, Mo, V, Mn, Ni) that work synergistically to provide both high temperature strength and thermal conductivity. The specific combination and ratios of these elements create a material that simultaneously satisfies both contradictory requirements
2Duration of action of stationary object
If alloy composition is optimized for high elevated temperature yield strength, then service life of roll shells is extended, but thermal conductivity is reduced which offsets the gain
Solution Approach 1:
The patent carefully controls the concentration parameters of each alloying element within specific ranges rather than maximizing any single element. This parameter control ensures that the steel achieves adequate elevated temperature yield strength for extended service life while maintaining thermal conductivity levels that support high casting speeds and production efficiency
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 lean alloy steel composition significantly increases the resistance to surface heat checking and casting speed while maintaining high thermal conductivity, thereby prolonging the service life and improving production efficiency of roll shells.
Implementation Method 1
The caster shells extract heat, so that the temperature of the aluminum falls below its melting point and becomes slightly solidified
Implementation Method 2
water-cooled, roll caster shells mounted on water-cooled cores
Data Source
AI summary
A lean alloy steel and roll shells made of same are provided. The lean alloy steel has improved properties in imparting high productivity and long service life for roll shells (or roll caster shells) utilized in the direct casting of molten materials (such as molten aluminum) to strips. The lean alloy steel includes iron (Fe) alloyed with carbon (C), chromium (Cr), molybdenum (Mo), vanadium (V), manganese (Mn), nickel (Ni), phosphorus (P), sulfur (S), silicon (Si), and/or niobium (Nb). The roll shells made from the heat treated lean alloy steel have high resistance to surface heat checking due to its very high yield strengths at molten aluminum temperatures (made, e.g., possible with its high carbide content), and have high casting speeds because of its high thermal conductivity (made, e.g., possible with its lean alloy composition).