Seamless Tube Thickness Deviation Control
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Solution Overview
Problem
Existing methods for manufacturing seamless tubes, particularly for air bag inflators, struggle to effectively suppress thickness deviations, especially in thin-walled tubes with a wall thickness of at most 4 mm, which limits the ability to reduce wall thickness without exceeding tolerance ranges.
Innovation Solution
Optimizing the soaking times in heating and reheating furnaces, with specific time ranges for billet and mother tube soaking, combined with cold drawing to reduce wall thickness deviations, allowing for a significant reduction in wall thickness tolerance to approximately 10% of the target value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the wall thickness of seamless tubes for air bag inflators is reduced to decrease weight, then weight reduction is achieved, but thickness deviation increases making it difficult to meet tolerance requirements
Solution Approach 1:
The patent applies parameter changes by optimizing the soaking time in the heating furnace based on the billet diameter (specific ranges provided in claims) to control the temperature distribution and phase transformation during piercing and elongation. This ensures uniform microstructure and minimizes thickness deviation even in thin-walled tubes, enabling weight reduction while maintaining precision
Solution Approach 2:
The patent implements preliminary action by performing controlled soaking of the billet in the heating furnace before piercing and elongation. This preliminary thermal treatment ensures uniform austenite formation and grain structure, preventing thickness deviation during subsequent forming operations and enabling production of thin-walled tubes with tight tolerances
2Device complexity
If conventional soaking times are used in heating and reheating furnaces, then manufacturing process is simple, but thickness deviation occurs in thin-walled tubes
Solution Approach 1:
The patent specifies precise soaking time parameters: in the heating furnace, soaking time is 0.05 to 0.20 minutes per mm of billet diameter, and in the reheating furnace, soaking time is 0.10 to 0.40 minutes per mm of mother tube outer diameter. These quantified parameter changes optimize thermal diffusion and phase transformation, suppressing thickness deviation while maintaining process simplicity through clear numerical guidelines
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 process effectively suppresses thickness deviations in seamless tubes for air bag inflators, enabling a substantial reduction in wall thickness while maintaining minimal tolerance, thus improving manufacturing efficiency and quality control.
Implementation Method 1
a billet which has been soaked in a heating furnace at a predetermined temperature for a predetermined length of time
Implementation Method 2
after soaking the mother tube in a reheating furnace at a predetermined temperature for a predetermined length of time
Data Source
AI summary
A process for manufacturing a seamless tube which can effectively suppress thickness deviations which are apt to occur in thin-walled seamless tubes is provided. A billet which has been soaked in a heating furnace at a given temperature for a given length of time is subjected to piercing and elongation rolling to form a mother tube, which is then soaked in a reheating furnace at a given temperature for a given length of time and then subjected to sizing to produce a seamless tube with a wall thickness of at most 4 mm. The wall thickness of the tube after sizing is at most 4 mm, the soaking time at the given temperature in the heating furnace is in the range of [billet diameter (mm)×(from 0.14-0.35 )] minutes, and the soaking time at the given temperature in the reheating furnace is in the range of [mother tube wall thickness (mm)×(from 3.0-10.0)] minutes.