The surface quality of 304 stainless steel plate is mainly determined by the
pickling process after heat treatment. If the surface oxide scale formed by the
previous heat treatment process is thick or the structure is uneven, pickling
will not improve the surface finish and uniformity. Therefore, we must pay full
attention to the heating of the heat treatment or the surface cleaning before
the heat treatment.
If the thickness of the surface oxide scale of the stainless steel plate is
uneven, the surface finish of the base metal under the thick and thin areas is
also different, and the dissolution of the surface oxide scale during pickling
and the degree of corrosion of the base metal at the attachment site of the
oxide scale by acid Different, so the surface of the steel plate is not uniform.
Therefore, during the heat treatment heating, it is necessary to uniformly form
oxide scales. To meet this requirement, we must pay attention to the following
issues:
If oil is attached to the surface of the stainless steel plate during
heating, the thickness of the oxide scale at the oil-attached part will be
different from the thickness and composition of the oxide scale on other parts,
and carburization will occur. The carburized part of the base metal under the
oxide skin will be severely corroded by acid. The oil droplets sprayed by the
heavy oil burner during the initial combustion will have a great influence if it
adheres to the workpiece. The fingerprint of the operator may also be affected
when it is attached to the workpiece. Therefore, do not touch the stainless
steel parts directly with your hands, and do not make the work pieces stained
with new oil. Must wear clean gloves to operate.
If there is lubricating oil attached to the surface of 304 stainless steel
plate during cold working, it must be fully degreased in trichloroethylene
degreasing agent and caustic soda solution, then cleaned with warm water, and
then heat treated.
If there are debris on the surface of the stainless steel plate, especially
when organic matter or ash adheres to the workpiece, heating will certainly
affect the oxide scale.
