Ultrasonic Weld Seam Stress Control for Thick Steel Joints
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Solution Overview
Problem
Welding residual stress at the seam of thicker steel parts, such as doors and windows, leads to stress concentration and potential deformation, affecting the firmness of the weld.
Innovation Solution
A control device and method using ultrasonic transducers with conical horn transmitting portions arranged on both sides of the welding seam, emitting continuous ultrasonic waves during welding to reduce stress concentration, improve grain distribution, and enhance the welding joint's performance by generating a plastic deformation layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welding is performed on thicker steel parts, then the structural strength and rigidity are improved, but welding residual stress and stress concentration at the seam increase
Solution Approach 1:
The patent applies ultrasonic vibration to the welding seam area during or after welding. The ultrasonic transducer generates high-frequency mechanical vibrations that are transmitted through the horn to the weld zone, creating a plastic deformation layer that redistributes stress and reduces residual stress concentration in thick steel structures.
Solution Approach 2:
The patent changes the physical state of the welding seam by applying ultrasonic vibration, which alters the material's mechanical properties in the affected zone. This creates a plastic deformation layer with modified density and crystalline structure, effectively reducing stress concentration while maintaining the structural strength gained from welding thick parts.
2Stability of the object's composition
If welding is performed on thicker steel parts, then the structural rigidity is improved, but stress concentration at the welding seam increases
Solution Approach 1:
Ultrasonic vibration is applied to the welding seam to generate mechanical vibrations that create a plastic deformation layer. This layer redistributes the stress concentration that naturally occurs at weld seams in rigid thick structures, reducing the harmful stress concentration while preserving the structural rigidity provided by the thick steel parts.
Solution Approach 2:
The patent converts the harmful stress concentration at the welding seam into a beneficial plastic deformation layer through ultrasonic vibration. The previously harmful stress concentration zone becomes a strengthened region with improved stress distribution, transforming the defect into an advantage while maintaining structural rigidity.
3Stress or pressure
If ultrasonic transducers are applied during welding, then welding residual stress is reduced and grain distribution is improved, but the device complexity increases
Solution Approach 1:
The ultrasonic treatment device is segmented into modular components: ultrasonic transducers, horns, and a control system. Multiple transducers can be arranged in arrays along the welding seam, allowing the system to handle different weld lengths and configurations. This modular segmentation makes the complex ultrasonic treatment process manageable and adaptable to various welding applications.
Solution Approach 2:
The patent replaces traditional mechanical stress relief methods (such as hammering or rolling) with an ultrasonic vibration system. This substitution reduces the need for complex mechanical equipment while achieving effective stress reduction and grain structure improvement through acoustic energy.
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 effectively reduces welding residual stress, improves the transition region between the seam and the base material, strengthens the metal near the seam, and ensures firm welding by uniformly distributing solutes and reducing segregation.
Implementation Method 1
continuous ultrasonic waves are continuously input during welding by controlling the plurality of ultrasonic transducers, and are radiated into a molten pool. Mechanical vibrations of the ultrasonic waves are transmitted to the welding seam of the welded parts in the process from a molten state to solidification of a weld toe
Data Source
AI summary
A control device for reducing and homogenizing welding residual stress by acoustic waves, comprising: a fixing tool having two rows of through holes; a plurality of ultrasonic transducers each having a body and a conical horn transmitting portion at a lower end of the body, wherein lower ends of the horn transmitting portions are fixedly connected with flanges, the horn transmitting portions of the ultrasonic transducers extend into respective through holes of the fixing tool to be in contact with welded parts below the fixing tool, the flanges are fixed to the fixing tool by bolts, and the two rows of through holes are arranged both sides of a welding seam of the welded parts; and a driving device for driving the ultrasonic transducers to operate. A corresponding control method is also provided. The control device can be used to control residual stress at the welding seam of steels.