Heat treatment can improve the quality of the product. The surface quality of the wear-resistant plate is mainly determined by the pickling process after heat treatment. This article talks about the relationship between the quality of the wear-resistant plate and heat treatment.
(1) If the surface oxide thickness of the wear-resistant 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 is closely related to the base metal at the oxide scale attachment site. The degree of acid erosion is different, so the surface of the wear-resistant plate is uneven. Therefore, during heat treatment and heating, the oxide scale must be formed uniformly. To achieve a certain level, the following conditions must be paid attention to:
If oil is attached to the surface of the workpiece during heating, the thickness and composition of the oxide scale at the oil-attached part will be different from the thickness and composition of the oxide scale at 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 ejected when the heavy oil burner is initially burned will also have a great impact if they adhere to the workpiece. The operator's fingerprints may also have an impact when attached to the workpiece. Therefore, workers should not touch the wear-resistant plates directly with their hands, and do not allow the workpiece to be stained with new oil. If there is lubricating oil attached to the surface of the workpiece during cold processing, it must be fully degreased in trichlorethylene degreasing agent or caustic soda solution. Then rinse with warm water and then heat treat.
(2) If there are debris on the surface of the workpiece, especially organic matter or ash attached to the workpiece, heating will of course have an impact on the oxide scale.
(3) There is a difference in the oxide scale produced on the surface of the wear-resistant plate where the gas or oil flame is in direct contact with the surface where it is not in contact. Therefore, the treatment piece must not be in direct contact with the flame port during heating.
(4) If there is residual oxide scale on a part of the treated part before heat treatment, there will be a difference in the thickness and composition of the oxide scale between the parts with residual oxide scale and the parts without oxide scale after heating, causing the surface to be uneven after pickling. Uniform, so not only the final heat treatment should be paid attention to, but also the intermediate heat treatment and pickling should be paid full attention to.
(5) The influence of different surface finish. If the surface finish is different, even if the same heating is performed, the oxide scale on the rough and fine parts of the surface will be different. For example, the conditions of oxide scale formation are different in places where local defects have been cleaned and in places that have not been cleaned, which causes uneven surface of the workpiece after pickling.
(6) Differences in the atmosphere in the furnace. The atmosphere in the furnace is different in various parts, and the formation of oxide scale will also change. This is also the reason for the unevenness after pickling. Therefore, during heating, the atmosphere in all parts of the furnace must be the same. For this reason, the circulation of the atmosphere must also be considered.
