Notes for heat treatment of bs1387 high quality cold form square and rectangular steel tube:
1. If the bs1387 high quality cold form square and rectangular steel tube adheres to the surface of the workpiece during heating, the thickness and composition of the oxide skin at the oil-attached part will be different from the thickness and composition of the oxide skin at other parts, and carburization will occur. The carburized part of the base metal under the oxide scale will be severely attacked by the acid. The oil droplets ejected by the heavy oil burner when it first burns will have a great impact if it adheres to the workpiece. It also affects when the operator's fingerprint is attached to the workpiece. Therefore, the bath maker should not directly touch the stainless steel parts with his hands, and do not make the workpieces stained with new oil. Clean gloves must be worn.
2. If there is lubricating oil attached to the surface of the workpiece during cold working, it must be fully degreased in trichloroethylene degreasing agent and caustic soda solution, then washed with warm water, and then heat treated.
If the bricks, asbestos, etc., which constitute the bench used for heating the workpiece, contain moisture, the moisture will evaporate during heating, and the atmosphere of the part that directly contacts the water vapor will be different from that of other parts, and the formation of oxide scale will of course be different. Therefore, objects in direct contact with the heated workpiece must be fully dried before they can be used. However, if it is placed at room temperature after drying, the moisture will still condense on the surface of the workpiece under the condition of high humidity. Therefore, it is better to dry before use.
3. If there is residual oxide scale on the part of the treated part before heat treatment, and there is residual oxide scale and no scale after heating, the thickness and composition of the scale will appear. The difference in the pickling caused the uneven surface after pickling, so not only should pay attention to the final heat treatment, but also pay full attention to the intermediate heat treatment and pickling.
4. There is a difference in the oxide scale produced on the stainless steel surface that is in direct contact with the flame of gas or oil and where it is not in contact. Therefore, it is necessary to prevent the treatment member from directly contacting the flame port during heating.
5. The surface cleanliness is different, even if the same heating, the oxide scale on the rough and fine parts of the surface is different. For example, in the places where the local defects have been cleaned and the places where they have not been cleaned, the conditions of the formation of oxide scale are different, so the surface of the workpiece after pickling is uneven.
6. If there are sundries on the surface of bs1387 high quality cold form square and rectangular steel tube, especially when organic matter or ash is attached to the workpiece, heating will certainly affect the oxide skin.
7. Differences in atmosphere in bs1387 high quality cold form square and rectangular steel tube furnace The atmosphere in the furnace is different in each part, and the formation of oxide scale will also change, which is also the reason for the unevenness after pickling. Therefore, when heating, the atmosphere of each part of the furnace must be the same. For this reason, the circulation of the atmosphere must also be considered.