High-Strength Tin Blackplate for Sealable Bottle Cap Forming

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Solution Overview

Problem

Existing tin blackplates used for lids such as beverage bottle caps lack sufficient workability, pressure resistance characteristics, and shape fixability, leading to potential leakage of contents due to non-uniform wrinkle shapes and insufficient sealing force.

Innovation Solution

A high-strength tin blackplate composition comprising specific alloying elements (C, Mn, Al, Cr, Cu, Ti) and controlled manufacturing processes, including hot-rolling, cold-rolling, and annealing, to achieve yield strengths of 570 to 700 MPa, surface hardness of 74 to 80 Hr30T, and optimized rolling reduction ratios.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional tin blackplates with lower strength are used, then workability and formability are improved, but pressure resistance characteristics deteriorate leading to potential leakage

Engineering Contradiction:
Improvepressure resistanceVSAvoidworkability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent applies parameter changes by precisely controlling the chemical composition parameters (C: 0.03-0.09%, Mn: 0.20-0.40%, Cr: 0.15-0.45%, Cu: 0.05-0.25%, Ti: 0.03-0.08%) and processing parameters (cold rolling reduction ratio: 5-20%, annealing temperature: 550-650°C) to achieve the optimal balance between strength and workability for crown plug applications

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite microstructure consisting of ferrite and bainite phases through controlled composition and processing. The combination of multiple alloying elements (C, Mn, Cr, Cu, Ti) works synergistically to produce a composite material structure that simultaneously provides high strength (570-700 MPa yield strength) and adequate workability

Inventive Principle:
Principle #40Composite materials

2Strength

If high-strength materials are used to improve pressure resistance, then sealing force is improved, but shape fixability and uniformity of wrinkle shape deteriorate

Engineering Contradiction:
Improvesealing forceVSAvoidshape fixability
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent uses parameter changes by controlling the cold rolling reduction ratio to 5-20% and annealing temperature to 550-650°C to achieve a yield strength of 570-700 MPa, which provides sufficient sealing force while maintaining shape fixability through the resulting microstructure

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by creating a specific microstructure distribution with ferrite and bainite phases that provides different properties in different contexts: high strength for sealing force while maintaining adequate ductility for shape fixability during the forming process

Inventive Principle:
Principle #3Local quality

3Quantity of substance

If ultra-thin materials are used to reduce weight, then material efficiency is improved, but workability for drawing processes deteriorates

Engineering Contradiction:
Improvematerial thicknessVSAvoiddrawing workability
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The patent applies parameter changes by precisely controlling the chemical composition (particularly C: 0.03-0.09% and Mn: 0.20-0.40%) to achieve a microstructure that provides adequate workability for drawing processes even in ultra-thin configurations (0.2-0.3 mm), while maintaining the required strength levels

Inventive Principle:
Principle #35Parameter changes

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 enhances workability, pressure resistance, and shape fixability, ensuring secure sealing and reducing processing defects, making it suitable for lids that require high strength and durability.

Implementation Method 1

0.03 to 0.09% of carbon (C); 0.2 to 0.4% of manganese (Mn); 0.01 to 0.06% of aluminum (Al); 0.15 to 0.45% of chromium (Cr); 0.05 to 0.25% of copper (Cu); 0.03 to 0.08% of titanium (Ti)

Methodology Applied
Scientific EffectSolid solution strengthening: Solid Solution Strengthening

Implementation Method 2

0.03 to 0.08% of titanium (Ti)

Methodology Applied
Scientific EffectPrecipitation hardening: Precipitation Hardening

Implementation Method 3

manufacturing a hot-rolled steel plate by hot-rolling the heated slab

Methodology Applied
Scientific EffectHot rolling: Heating

Implementation Method 4

subjecting the annealed cold-rolled steel plate to secondary cold rolling

Methodology Applied
Scientific EffectCold rolling: Compression

Implementation Method 5

annealing the cold-rolled steel plate

Methodology Applied
Scientific EffectAnnealing: Annealing

Data Source

PatentUS12553112B2High-strength blackplate and manufacturing method therefor
Publication Date: 2026.02.17 POHANG IRON & STEEL CO LTD

AI summary

The present invention provides a high-strength tin blackplate and a manufacturing method therefor.The tin blackplate according to an exemplary embodiment of the present invention includes: by wt %, 0.03 to 0.09% of carbon (C); 0.2 to 0.4% of manganese (Mn); 0.01 to 0.06% of aluminum (Al); 0.15 to 0.45% of chromium (Cr); 0.05 to 0.25% of copper (Cu); 0.03 to 0.08% of titanium (Ti); and the balance of iron (Fe) and inevitable impurities, and has a yield strength of 570 to 700 MPa.