Ceramic-Coated Welding Support Block for Copper-Free Pipe Welding
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Solution Overview
Problem
Existing welding support technologies face challenges in preventing copper contamination during pipe welding, especially in sour service conditions, where copper backing shoes risk melting and contaminating the weld pool, and ceramic alternatives suffer from thermal shock and high production costs.
Innovation Solution
A welding support block comprising a steel base with a thin ceramic layer (0.25 mm to 1.5 mm thick) positioned between the steel and the weld pool, providing thermal insulation and protection against copper contamination, allowing for faster production rates and reduced maintenance costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If copper backing shoes are used to support the weld pool, then heat conduction is improved and weld pool cooling is enhanced, but copper contamination of the weld pool occurs leading to weld quality degradation
Solution Approach 1:
The invention uses a composite structure consisting of a copper base material combined with a ceramic coating layer. The copper provides excellent thermal conductivity for weld pool cooling, while the ceramic coating prevents copper contamination of the weld pool. This composite material approach resolves the contradiction by combining materials with complementary properties.
Solution Approach 2:
The ceramic coating acts as an intermediary barrier between the copper backing shoe and the weld pool. It allows thermal energy to pass through for cooling while preventing direct contact and contamination between copper and the weld pool, thus mediating the interaction between these two components.
2Object-affected harmful factors
If ceramic support blocks are used to prevent copper contamination, then weld pool contamination is prevented, but thermal shock resistance is poor leading to material breakdown and spalling
Solution Approach 1:
The composite structure of copper base with ceramic coating combines the contamination-resistant properties of ceramic with the thermal shock resistance of copper. The copper base absorbs thermal shocks while the ceramic coating maintains its protective function, resolving the reliability issue of pure ceramic supports.
Solution Approach 2:
Different parts of the support block have different material properties optimized for their specific functions: the copper base provides thermal shock resistance and heat conduction, while the ceramic coating provides contamination prevention. This local differentiation of material qualities resolves the contradiction.
3Object-affected harmful factors
If ceramic coating layer is made thick to prevent copper exposure, then contamination protection is improved, but heat conduction capability deteriorates
Solution Approach 1:
The invention optimizes the thickness parameter of the ceramic coating to a specific range that balances protection and heat conduction. By controlling the coating thickness within this optimal range, both contamination protection and thermal efficiency are maintained simultaneously.
4Productivity
If copper backing shoes are used for sour service pipelines, then production rate is improved, but weld hardness control and crack susceptibility increase
Solution Approach 1:
The ceramic coating serves as an intermediary barrier that enables the use of copper backing shoes for sour service pipelines by preventing copper contamination. This allows high-speed welding to proceed while maintaining weld integrity and controlling hardness, thus resolving the contradiction between productivity and reliability.
Solution Approach 2:
The composite copper-ceramic structure enables copper backing shoes to be used safely for sour service pipelines. The ceramic layer prevents copper pick-up in the weld while the copper base provides thermal management, allowing high productivity without compromising weld integrity under sour service conditions.
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 ceramic-coated steel support block effectively prevents copper contamination, reduces the need for frequent inspection and replacement, and enhances welding productivity by maintaining weld quality and integrity, even under high-temperature sour service conditions.
Implementation Method 1
The ceramic material has a high degree of resistance to high temperature but also tends to suffer from a low resistance to thermal shock
Implementation Method 2
The use of copper as the main bulk material of the back support pads is because copper has a high thermal conductivity, which is desirable as it reduces the risk of the pad itself being melted during the welding process, since heat is quickly and efficiently conducted away
Implementation Method 3
Welding onto copper backing shoes during the root pass, where there is exposure to the extreme temperatures of a welding arc
Data Source
AI summary
A welding support block supports, from the rear surface of a joint to be welded, a weld pool created during a welding process. The welding support block comprises a block of metal and an outer layer of ceramic material providing a supporting surface. The ceramic material layer has a thickness between 0.25 mm and 1.5 mm. The metal material immediately beneath the ceramic material layer is made of steel. An internal line-up clamp for holding pipes in end-to-end alignment ready for welding may include multiple such welding support blocks. The use of such welding support blocks is particularly useful when laying a sour service carrying pipeline (high H2S content).