Temper Bead Welding Criteria for Pressure-Bearing Steel Repairs
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Solution Overview
Problem
There is a lack of research on the applicability of temper bead welding in pressure-bearing special devices, limiting its application, especially in materials and welding methods, without clear criteria for determining suitability.
Innovation Solution
A method to determine a tempering temperature range (ΔTw) by establishing a calculation model, obtaining thermal cycle curves, and adjusting welding parameters to ensure the suitability of temper bead welding, including determining the suitability of materials and processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If temper bead welding is applied to expand application to pressure-bearing special devices, then versatility is improved, but reliability is worsened due to lack of clear applicability criteria
Solution Approach 1:
The patent establishes specific parameter ranges including tempering temperature (Ac1-50℃ to Ac1-10℃), welding heat input (3.5-6.5 kJ/mm), and bead geometry parameters to define applicable conditions for temper bead welding in pressure-bearing special devices, transforming the vague applicability into quantifiable criteria
2Strength
If post-weld heat treatment is applied to improve performance, then strength is improved, but device complexity is worsened due to additional process steps
Solution Approach 1:
The patent merges the welding process with the heat treatment process by using the welding bead itself as the heat source for tempering the heat-affected zone. The welding parameters are optimized to simultaneously achieve sound welds and appropriate tempering effects, eliminating the need for separate post-weld heat treatment equipment and processes
Solution Approach 2:
The welding process itself provides the thermal energy needed for heat treatment. The welding bead geometry and heat input are designed to automatically create the necessary thermal cycle for tempering the heat-affected zone, making the system self-sufficient without external heat treatment intervention
3Reliability
If welding repair is applied to eliminate damage, then reliability is improved, but residual stress increases worsening the structural integrity
Solution Approach 1:
The patent converts the harmful welding thermal cycle that causes residual stress and hardening into a beneficial tempering process. By carefully controlling bead geometry and heat input, the subsequent welding passes or the same pass creates a thermal cycle that tempers the heat-affected zone, transforming the harmful thermal effect into a stress-relieving and microstructure-improving process
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 method provides a method to determine a tempering temperature range (ΔTw) by establishing a calculation model, obtaining thermal cycle curves, and adjusting welding parameters to ensure the suitability of temper bead welding, thereby expanding its application to pressure-bearing special devices.
Implementation Method 1
the welding bead is melted at a specific position or a weld surface in order to affect the metallurgical performances of the heat-affected region or previously melted weld metal
Implementation Method 2
affect the metallurgical performances of the heat-affected region
Implementation Method 3
Post-weld heat treatment is usually required to improve the performance
Data Source
AI summary
An obtaining method of the tempering temperature range includes following operations: determining a determination criterion of a tempering weld bead effect of a steel obtained after a welding of; determining an Ac1 temperature at which the steel begins to form or transform into austenite during a welding heating process; obtaining a temperature field distribution during a welding process, and determining a thermal cycle curve and a size distribution of the temperature field in different temperature ranges; using different peak tempering temperatures to simulate the thermal cycle curve and test performances on a microstructure of a weld coarse grained region, and determining a lowest peak temperature Tw and a highest peak temperature Tp meeting the determination criterion; and obtaining the tempering temperature range ΔTw according to the highest peak temperature Tp and the lowest peak temperature Tw of the steel, wherein Tp=Ac1 for some steel.