Heat treatment of propylene spheres
Thread Content
One year after operation, an inspection was carried out on the propylene sphere tank in our plant, and multiple defects were found at the welds. After repair, heat treatment needs to be performed again. But I’ve encountered such a situation: it has been raining frequently lately, which will affect heat treatment. I would like to ask everyone, what impact will rain have on the equipment during the heat treatment process?
In rainy weather, if there are no proper measures to protect against rain, the water can soak through the insulation cover, which is equivalent to quenching the tank plates; this increases the surface hardness of the tanks and raises the stress at the joints, thereby failing to achieve the effect of stress-relief heat treatment
Work is generally not carried out in the afternoon. If it really rains, the welded joints are quenched, which results in coarse crystal structures; the material becomes brittle and is prone to failure due to stress concentration
If heat treatment cannot be carried out due to rain, one of the functions of heat treatment is to remove hydrogen; rainy weather increases the hydrogen content, which makes the welds more brittle
The heat treatment carried out upon opening the can is usually local electric heating; overall heat treatment is rare as it is very costly. All forms of local heat treatment can effectively avoid this problem. . . .