Key points of production process of brass plates and strips
The key points of the production process of brass plates and strips are as follows:
1. Ingot heating. High-zinc brass is easy to "dezincify" at high temperatures, and some complex brasses have large casting stresses. Therefore, most brasses are not suitable for high-temperature rapid heating. The atmosphere in the furnace should be a slightly oxidizing atmosphere.
2. Hot rolling. Some brasses (such as high-zinc brass, etc.) have brittle β phases in addition to α phase at high temperatures. It is best to avoid the brittle temperature zone during hot rolling to avoid cracks. Low-zinc simple brass (such as H96, H90, etc.) has good plasticity and can be hot-rolled in a large temperature range, while some complex brasses such as lead brass have limited high-temperature plasticity, so the temperature range of hot rolling is narrow. Rapid rolling should be implemented and attention should be paid to cooling.
3. Cold rolling. Simple brass also has quite good plasticity, and the processing rate can reach more than 75%, while most complex brasses have poor plasticity, and some have a processing rate of less than 50%. Therefore, room should be left when designing the total processing rate to avoid cracking and breaking.
4. Annealing. Some brasses (such as HPb59-1, H62, etc.) are sensitive to internal stress and should be annealed within 24 hours after cold working to avoid self-cracking or deformation (such as oil scoop) due to large internal stress. For high-zinc brass, the annealing temperature should be taken to the lower limit to prevent high-temperature dezincification, which will cause "pitted" defects in the product. Because the zinc in brass has a degassing effect during casting, the gas content in the metal is relatively low, so the hydrogen content in the protective gas during annealing can be higher than that during copper annealing.
5. Cleaning and finishing. When pickling brass, the acid concentration should not be too high and the time should not be too long to avoid "dezincification" due to over-pickling. High-zinc brass hard and semi-hard products should not be straightened repeatedly, otherwise stress relief annealing must be carried out in time.
