One-Side Butt Welding with Ceramic Backing for Stable Root Pass
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Solution Overview
Problem
Conventional gas-shielded arc welding methods for one-side butt welding of steel plates face challenges in achieving high procedure efficiency and weld quality, particularly in reducing welding heat input while minimizing the risk of incomplete fusion and hot cracking, especially with increasing steel plate thickness.
Innovation Solution
A gas-shielded arc welding method that uses a ceramic-made backing material and specific welding conditions, including a welding current of 200 to 450 A, voltage of 25 to 50 V, and a controlled welding heat input within the range defined by the formula 0.4×G−1 ≤Q≤0.6×G+1, where G is the root gap, to perform a root pass in one pass without a special device, utilizing a welding wire with 0.015 to 0.100% rare earth metal and straight polarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If multi-layer multi-pass welding is used to reduce welding heat input, then welding heat input is reduced, but the number of welding passes increases and procedure efficiency decreases
Solution Approach 1:
The invention changes the parameters of the root pass welding by using a specific welding current range (200-450A) and welding voltage range (25-50V) to achieve optimal penetration and fusion. This parameter optimization allows the root pass to be completed in one pass with reduced heat input, eliminating the need for multiple passes while maintaining procedure efficiency.
2Productivity
If the groove angle or root gap is reduced to reduce the number of welding passes, then the number of welding passes is reduced, but welding defects such as incomplete fusion of the groove walls occur
Solution Approach 1:
The invention uses specific parameter ranges for welding current (200-450A) and welding voltage (25-50V) to ensure complete fusion of the groove walls even when the groove angle is 35° or less. These parameter changes provide sufficient heat input and arc control to prevent incomplete fusion while maintaining a reduced groove geometry that allows one-pass welding.
Solution Approach 2:
The invention incorporates feedback control through monitoring the welding current and voltage to maintain them within the specified ranges. This feedback mechanism ensures that the welding parameters remain optimal throughout the process, preventing welding defects such as incomplete fusion even in narrow groove conditions.
3Ease of manufacture
If conventional welding methods are used for one-side butt welding, then the welding process is simple, but high procedure efficiency and good weld quality cannot be achieved simultaneously
Solution Approach 1:
The invention optimizes the welding parameters by specifying a welding current of 200-450A and welding voltage of 25-50V for the root pass. These parameter changes enable one-pass completion of the root pass with good weld quality, achieving high procedure efficiency while maintaining the simplicity of the welding process and avoiding the need for special devices.
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 method achieves high procedure efficiency and weld quality with reduced welding defects, such as incomplete fusion and hot cracking, by stabilizing the arc and ensuring proper penetration, even at narrow groove angles and small root gaps, thereby enhancing the structural integrity of the welded joints.
Implementation Method 1
gas-shielded arc welding method
Implementation Method 2
gas-shielded arc welding method
Data Source
AI summary
Provided are a gas-shielded arc welding method, a welded joint, and a method for producing the welded joint. In gas-shielded arc welding including one-side butt welding of steel plates in the present invention, a ceramic-made backing material is attached to a bottom surface of a groove, and root pass is performed in one pass using a welding current I of 200 to 450 A and a welding voltage V of 25 to 50 V while a welding heat input Q is controlled within the range defined by formula 1 below.0.4× G−1 ≤Q ≤0.6× G+1 (formula 1)Here, G in formula 1 is a root gap (mm).