Bainitic Steel Threaded Spindle Cold Forming
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Solution Overview
Problem
The existing production methods for threaded spindles require high energy for heating and quenching processes during hardening, leading to complex cleaning and potential dimensional inaccuracies, while also requiring specialized equipment for forming bainitic steels with higher initial strength.
Innovation Solution
A threaded spindle is produced using bainitic steel with a bainitic structure, where the material is formed through cold forming processes without subsequent heat treatment, resulting in a core shell with high hardness and a thread that is more ductile than the core shell, allowing for improved force dissipation and dimensional accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If transformation hardening or vacuum hardening is performed to achieve necessary final hardness, then material strength is improved, but energy consumption increases and dimensional accuracy deteriorates
Solution Approach 1:
The patent changes the material parameters by selecting specific steel grades (1.5519, 1.5520, 1.5521, 1.5522, 1.5523, 1.5524, 1.5525, 1.5526, 1.5527, 1.5528, 1.5529, 1.5530, 1.5531, 1.5532, 1.5533, 1.5534, 1.5535, 1.5536, 1.5537, 1.5538, 1.5539, 1.5540, 1.5541, 1.5542, 1.5543, 1.5544, 1.5545, 1.5546, 1.5547, 1.5548, 1.5549, 1.5550, 1.5551, 1.5552, 1.5553, 1.5554, 1.5555, 1.5556, 1.5557, 1.5558, 1.5559, 1.5560, 1.5561, 1.5562, 1.5563, 1.5564, 1.5565, 1.5566, 1.5567, 1.5568, 1.5569, 1.5570, 1.5571, 1.5572, 1.5573, 1.5574, 1.5575, 1.5576, 1.5577, 1.5578, 1.5579, 1.5580, 1.5581, 1.5582, 1.5583, 1.5584, 1.5585, 1.5586, 1.5587, 1.5588, 1.5589, 1.5590, 1.5591, 1.5592, 1.5593, 1.5594, 1.5595, 1.5596, 1.5597, 1.5598, 1.5599, 1.5600) with inherent high strength properties that eliminate the need for post-forming heat treatment. The material's initial strength Rm is at least 800 MPa, and after cold forming achieves 1000 MPa or higher without additional hardening processes, thereby avoiding energy consumption and dimensional changes associated with heat treatment.
2Strength
If transformation hardening or vacuum hardening is performed to achieve necessary final hardness, then material strength is improved, but manufacturing complexity increases
Solution Approach 1:
The patent changes the material parameters by selecting specific steel grades (1.5519, 1.5520, 1.5521, 1.5522, 1.5523, 1.5524, 1.5525, 1.5526, 1.5527, 1.5528, 1.5529, 1.5530, 1.5531, 1.5532, 1.5533, 1.5534, 1.5535, 1.5536, 1.5537, 1.5538, 1.5539, 1.5540, 1.5541, 1.5542, 1.5543, 1.5544, 1.5545, 1.5546, 1.5547, 1.5548, 1.5549, 1.5550, 1.5551, 1.5552, 1.5553, 1.5554, 1.5555, 1.5556, 1.5557, 1.5558, 1.5559, 1.5560, 1.5561, 1.5562, 1.5563, 1.5564, 1.5565, 1.5566, 1.5567, 1.5568, 1.5569, 1.5570, 1.5571, 1.5572, 1.5573, 1.5574, 1.5575, 1.5576, 1.5577, 1.5578, 1.5579, 1.5580, 1.5581, 1.5582, 1.5583, 1.5584, 1.5585, 1.5586, 1.5587, 1.5588, 1.5589, 1.5590, 1.5591, 1.5592, 1.5593, 1.5594, 1.5595, 1.5596, 1.5597, 1.5598, 1.5599, 1.5600) with inherent high strength properties that eliminate the need for post-forming heat treatment. The material's initial strength Rm is at least 800 MPa, and after cold forming achieves 1000 MPa or higher without additional hardening processes, thereby eliminating complex heat treatment equipment and vacuum hardening facilities from the manufacturing system.
3Strength
If bainitic steel with higher initial strength is used, then final strength is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent changes the material parameters by selecting specific bainitic steel grades with optimized composition and microstructure. These steels have an initial strength Rm of at least 800 MPa in the drawn state, yet maintain sufficient formability for cold forming operations. The key is the specific chemical composition and bainitic microstructure that provides a balance between initial strength and formability, allowing cold forming without subsequent heat treatment while achieving final strength of 1000 MPa or higher.
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
This approach simplifies the production process, maintains high final strength, and ensures better force absorption and elasticity compared to classically manufactured spindles, with the core shell dissipating forces and the thread being more ductile, thus enhancing operational performance.
Implementation Method 1
the work hardening that occurs during cold forming increases the material strength again
Data Source
Figure 1~3
Figure 4
AI summary
A threaded spindle (20, 30), with at least one substantially cylindrical, thread-bearing first section (24), is manufactured from a blank of bainitic steel. After exclusively cold forming processes without subsequent hardening processes, the hardness of the threaded spindle in the flank region (36) is lower than the hardness of the threaded spindle in a core shell (34), despite a higher degree of deformation. The threaded spindle therefore offers advantages in terms of strength and elasticity.