Q345R normalized plate – is normalization required after flame cutting?
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This post was last edited by yxj197612 on 2016-10-16 11:25. Q345R normalized steel plates – is normalization required after flame cutting? Some experts believe that flame cutting destroys its normalized state, so re-normalization is required after flame cutting. Please share your opinions
No need; there will be a final heat treatment after the overall assembly, so it can be done that way
If this expert believes that Q345R normalized steel plates still need to be normalized after flame cutting, then he’s really an expert in nonsense
But I still think the state has been partially damaged
After welding the problematic parts, only stress-relief heat treatment is carried out, not normalizing treatment
It depends on the finishing temperature for shaping or assembly heat treatment; if this finishing temperature is not lower than the minimum normalizing temperature of the material, it essentially constitutes a normalizing heat treatment process.
At the flame cutting area, samples can be taken for performance testing and verification
Yes, generally the final heat treatment is at 620°C; the final heat treatment is not normalizing
Indeed, the mechanical properties of the heat-affected zone change after flame cutting. However, the cut ends of Q345R steel plates usually still require welding, and during the processing (machining or grinding) of the welding grooves, the heat-affected zone from cutting has typically been removed. The subsequent welding process will also alter the mechanical properties of the material, so it is necessary to verify this through welding procedure qualification. During flame cutting, carbon arc gouging, and welding, the temperature in certain areas can exceed the normalizing temperature, but it is not necessary to carry out normalizing treatment as a result.
I agree with what was said on floor 9: if heat treatment is still required after simply using flame cutting in order to maintain the appropriate thermal condition of the cut area, it’s too costly. Moreover, heat treatment processes involve a certain holding time, while the cutting process itself is relatively short-lived; the experts’ approach seems a bit arbitrary!
However, along the cut surface, the metal undergoes heating and cooling processes from room temperature to the weakening temperature; undoubtedly, this portion of the metal cannot retain the normalized state of the raw material