Vibration on a continuous casting roller table, seemingly a subtle dynamic change, can have a cascading impact on the billet forming process. Irregular roller vibrations first disrupt the stability of the billet during conveyance. Billets are relatively soft at high temperatures. When subjected to continuous vibration, they are susceptible to slight displacement or wobble at the contact points with the rollers. This instability is directly reflected in the billet's surface quality, potentially causing unevenness or even microcracks, creating hidden dangers for subsequent processing.
Vibration also has a significant impact on the internal quality of billets cast on a continuous casting roller table. During the continuous casting process, the metal structure within the billet undergoes a critical stage of solidification and crystallization, and its structure is not yet fully stable. Roller vibrations are transmitted to the billet through contact, disrupting the normal growth order of the metal grains, potentially leading to uneven grain distribution and localized porosity or segregation. Although these internal defects may not be directly noticeable, they can severely affect the mechanical properties of the billet, reducing its strength and toughness, making the final product more susceptible to breakage or damage during use.
The dimensional accuracy of ingots cast on a continuous casting roller table can also be affected by roller vibration. Continuous casting production has strict requirements for the cross-sectional dimensions of ingots, requiring precise roller conveying to ensure consistent forming. When the rollers vibrate, their conveying path can exhibit slight deviations, resulting in irregular fluctuations in the width and thickness of the ingot. These dimensional deviations complicate subsequent rolling or processing. Excessive deviations may even require additional trimming of the ingot, wasting raw materials, extending production cycles, and reducing overall efficiency.
Vibration can also exacerbate oxidation and wear on the ingot surface. High-temperature ingots are prone to forming an oxide layer when exposed to air, and roller vibration creates additional friction and collision between the ingot and the rollers. This mechanical action disrupts the relatively uniform oxide layer on the ingot surface, leading to increased localized oxidation and the formation of thicker scales. Furthermore, the friction caused by vibration can cause excessive wear of the metal on the ingot surface, resulting in metal loss and increased production costs. These wear marks can also affect the fit between the rollers and the ingot in subsequent processes.
Roller vibration has a more direct impact on the straightening process of continuous casting roller tables. The straightening process in the later stages of continuous casting requires stable support to adjust the shape of the strand. If the rollers vibrate during this process, the straightening force will fluctuate, making it unevenly applied to the strand. This can cause the strand to bend or twist, failing to meet the required straightness requirements. In severe cases, re-straightening may be necessary, increasing the complexity of the process and potentially further damaging the strand structure due to repeated stress.
The instability caused by vibration also affects the cooling efficiency of the strand. During the continuous casting process, the strand must be uniformly cooled by cooling water to control its solidification rate and internal structure. Roller vibration can cause fluctuations in the residence time of the strand in the cooling zone, resulting in inconsistent cooling rates in different areas and temperature gradients. This uneven cooling can generate internal stress within the strand. When the stress accumulates to a certain level, it can cause deformation or cracking of the strand. This risk is particularly prominent in areas with drastic temperature fluctuations.
From the perspective of production continuity, roller vibration can cause strand transport to become jammed or stagnant. Excessive vibrations can even cause the strands to shift on the rollers, colliding with other equipment components and disrupting production. This unforeseen situation not only impacts the production schedule for that shift but can also cause the strands to cool too quickly due to prolonged retention, necessitating reheating before further processing. This consumes additional energy and increases the risk of equipment failure, impacting the stable operation of the entire production line.
