Can Steel Sheet Composition for High Strength and Workability
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Solution Overview
Problem
Conventional steel sheets for cans face challenges in achieving both high tensile strength and sufficient elongation, particularly in thin-gauge applications, which are necessary for reducing material thickness and ensuring workability in can manufacturing processes.
Innovation Solution
A steel sheet composition with specific ranges of C, Si, Mn, P, Al, N, Nb, B, and optionally Ti or Mo, combined with a microstructure containing at least 1.0% pearlite, is produced through controlled heating, hot rolling, cold rolling, annealing, and temper rolling to achieve yield stress of 500 MPa or more, tensile strength of 550 MPa or more, and uniform elongation of 10% or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a chromium-containing steel sheet is used to ensure food safety and prevent heavy metal contamination, then the safety of food storage is improved, but the production cost increases due to the need for expensive chromium-containing steel and complex surface treatments
Solution Approach 1:
The invention extracts and removes chromium from the steel composition entirely, replacing it with aluminum and silicon-based oxidation-resistant alloys. This eliminates the need for expensive chromium-containing steel while maintaining food safety and corrosion resistance through alternative mechanisms (aluminum oxide and silicon oxide layers).
Solution Approach 2:
The invention changes the chemical composition parameters of the steel sheet by specifying aluminum content at 0.03-2.00% and silicon content at 0.03-2.00%, replacing the traditional chromium-containing composition. This parameter change maintains oxidation resistance and food safety while reducing production costs by eliminating chromium.
2Reliability
If the steel sheet surface is made smooth to prevent bacterial adhesion and ensure food safety, then hygiene is improved, but the surface treatment process becomes more complex and costly
Solution Approach 1:
The invention incorporates oxidation-resistant elements (aluminum and silicon) directly into the steel composition during manufacturing, creating a protective oxide layer that provides smooth, hygienic surface properties before the can is even formed. This preliminary action eliminates the need for subsequent complex surface treatment processes.
Solution Approach 2:
The steel sheet performs self-protection against oxidation and corrosion through its inherent aluminum and silicon content, which automatically forms protective oxide layers. This self-service mechanism creates a smooth, non-bacterial surface without requiring external surface treatment processes, simplifying manufacturing.
3Duration of action of stationary object
If the steel sheet has high oxidation resistance to prevent rust and extend shelf life, then product durability is improved, but the material composition becomes more complex requiring multiple alloying elements
Solution Approach 1:
The invention optimizes the parameters of aluminum (0.03-2.00%) and silicon (0.03-2.00%) content to achieve high oxidation resistance. By carefully controlling these parameters, the steel sheet forms stable aluminum oxide and silicon oxide layers that prevent rust and extend shelf life without requiring complex multi-element compositions.
Solution Approach 2:
The invention creates a composite protective layer on the steel surface consisting of aluminum oxide and silicon oxide. This composite material structure provides superior oxidation resistance and extends shelf life while maintaining a relatively simple base steel composition without chromium.
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 enables further reduction in steel sheet thickness for cans while maintaining high strength and excellent workability, facilitating resource savings and cost reduction.
Implementation Method 1
contains aluminum and silicon that form an oxidation-resistant alloy
Implementation Method 2
the steel sheet is annealed to ensure that the total linearity is 10% or more
Implementation Method 3
steel sheets are stored in a state where oils or the like are applied thereto in order to prevent oxidation and corrosion
Data Source
AI summary
It is an object to provide a steel sheet for cans having high strength and excellent workability and a method for manufacturing the same. A steel sheet for cans has a chemical composition containing, in mass percent, C: 0.085% to 0.130%, Si: 0.04% or less, Mn: 0.10% to 0.60%, P: 0.02% or less, S: more than 0.010% to 0.020%, Al: 0.02% to 0.10%, N: 0.0005% to 0.0040%, Nb: 0.007% to 0.030%, and B: 0.0010% to 0.0050%, B/N that is the ratio of the content (mass percent) of B to the content (mass percent) of N being 0.80 or more, the remainder being Fe and inevitable impurities, and a ferrite microstructure containing 1.0% or more pearlite in terms of area fraction. The steel sheet for cans has a yield stress of 500 MPa or more, a tensile strength of 550 MPa or more, a uniform elongation of 10% or more, and a yield elongation of 5.0% or less.