Carbide Saw Blade Welding with Two-Stage Tempering
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Solution Overview
Problem
The existing welding methods for carbide saw blades face challenges in controlling temperature and time, leading to inconsistent hardness of the tooth holder, which causes safety issues such as breaking during cutting, and tensile stress cracking between adjacent sawteeth due to incomplete stress elimination during tempering.
Innovation Solution
A method involving heating the carbide tool bit, welding wire, and saw blade base to 760° C.-840° C., followed by tempering in stages to achieve a consistent temperature distribution within a sealed container, using induction coils and specific welding fluxes like h285 or UN285, to stabilize the hardness and reduce stress between sawteeth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual welding or automatic equipment welding is used with conventional tempering, then the welding process can be completed, but the tempering cannot completely eliminate the stress of the base tooth holder and reduce the hardness, resulting in inconsistent hardness and high hardness of the tooth holder
Solution Approach 1:
The patent applies preliminary action by performing a first tempering process immediately after welding when the temperature is below 350°C, followed by a second tempering process 1-3 hours later. This two-stage preliminary tempering approach ensures that stress elimination and hardness reduction occur in a controlled sequence, preventing both tooth holder breaking and ensuring consistent hardness across the blade.
Solution Approach 2:
The patent changes the tempering parameters by specifying different temperature ranges and time durations for two distinct tempering stages. The first tempering occurs at below 350°C for immediate stress relief, while the second tempering occurs at 380-480°C for 3-5 hours to achieve complete stress elimination and uniform hardness reduction, transforming the material properties through controlled parameter variation.
2Reliability
If conventional tempering is used, then the welding process can be completed, but the stress between adjacent sawteeth is not completely eliminated, leading to tensile stress cracking
Solution Approach 1:
The patent applies preliminary action by implementing a second tempering process that occurs 1-3 hours after the first tempering. This delayed second tempering ensures that residual stresses from the welding and first tempering processes are completely eliminated before the blade is put into service, preventing tensile stress cracking while maintaining a reasonable production timeline.
Solution Approach 2:
The patent changes the tempering parameters by extending the total tempering time to 3-5 hours with the second tempering occurring at 380-480°C. This extended time and temperature range ensures complete stress elimination between adjacent sawteeth, transforming the microstructure sufficiently to prevent cracking while balancing production efficiency.
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 stabilizes the hardness of the tooth holder, reduces the risk of breaking, and eliminates tensile stress cracking between sawteeth, enhancing product reliability and safety by ensuring uniform tempering across the carbide saw blade.
Implementation Method 1
to heating, first temper and/or second temper the carbide tool bit, the welding wire, the welding flux and the saw blade base by using an induction coil
Implementation Method 2
spreading the melted welding wire to the gap between the carbide tool bit and the saw blade base by using the wetting action of the welding flux
Implementation Method 3
tempering could not completely eliminate the stress of the base tooth holder and reduce the hardness of the base tooth holder
Data Source
AI summary
A carbide saw blade and the welding method of the carbide saw blade includes: S1, heating the carbide tool bit, the saw blade base (the saw blade base's tooth seat part), the welding wire and the welding flux that well-placed; S2, at temperature 760° C.-840° C., spreading the melted welding wire to the gap between the carbide tool bit and the saw blade base by using the wetting action of the welding flux; S3, cooling to obtain a preliminary welding body, when the temperature of the preliminary welding body is lower than 350° C., the preliminary welding body will be processed to first tempering; S4, within 1-3 hours after first tempering, second tempering the preliminary welding body to obtain carbide saw blade; second tempering process is performed in a sealed container, and in this container the temperature of each spatial location is consistent.