From the perspective of steel companies, steel rolling occupies a very important position. At present, the quality of products has been continuously improved, and it has gradually become more automated, and the control accuracy has also been greatly improved. This has further established the important position of technology in steel rolling hydraulic equipment. Steel rolling equipment contains hydraulic systems, which mainly have the following characteristics:
(1) The distribution of hydraulic pump stations is relatively concentrated, while the distribution of control valves is relatively scattered, operating through complex actuators.
(2) The pressure in the system is high and the flow rate is relatively large.
(3) High operating frequency and short response time.
(4) uses many high-precision control valves.
(5) The structure is complex and has many parts.
(6) The working environment is greatly affected by the outside world and the conditions are very harsh.
(7) Hydraulic systems can operate for long periods of time.
Based on the above characteristics, we found that failures in hydraulic systems are common, and these failures are generally difficult to find and troubleshoot. Although these faults are difficult to eliminate, their existence will inevitably hinder the normal operation of the hydraulic system, and will also cause certain harm to the environment, resulting in an unreasonable increase in rolling costs. It can be seen that for steel rolling equipment, certain measures must be taken to effectively prevent the occurrence of hydraulic leakage problems.
Analysis of the causes of 1 leakage
Looking at the entire hydraulic system, the hydraulic oil first comes out of the tank and is then used through various links. Therefore, there is a possibility of system leakage in every link. For a steel rolling equipment, there are many reasons that can lead to leakage of the hydraulic system. In summary, the main reasons are as follows.
(1) Movement and impact. The transmission power of the hydraulic system is relatively large, and the response speed is relatively fast, which may bring a large impact force and cause parts to become loose, which will lead to leakage problems in the hydraulic system.
(2) The seal is damaged. Unreasonable selection and assembly of seals, coupled with inappropriate groove dimensions, will cause certain damage to the seals and cause leakage in the hydraulic system. In addition, if the seals are aged or worn due to prolonged use, they may cause system leakage.
(3) High temperature. Hot-rolling equipment inevitably experiences radiant heat and generates substantial heat during operation, causing system temperature to rise. High-temperature leakage mainly occurs in two ways: ① excessive temperature lowers hydraulic-oil viscosity, allowing leakage through clearances; ② heat progressively ages nonmetallic seals, damaging the sealing structure and causing leakage.
③ Hydraulic oil deteriorates due to excessive temperature and gradually loses its lubrication performance, which leads to the appearance of wear sites and further causes leakage problems. ④ Hydraulic components expand excessively due to excessive temperature, which blocks the normal operation of the valve core and causes leakage problems.
(4) The gap becomes larger. The joint surface is generally sealed, but if the gap is worn, it will gradually become larger, eventually leading to leakage problems.
(5) Impurity contamination. Impurities can also cause wear problems and may affect the normal operation of the valve core. These are the main reasons for leakage problems.
2 Main measures to control leakage
Overall, there is a long way to go to effectively prevent hydraulic system leakage, and it is very systematic and needs to be ensured from all aspects of design, structure, and debugging. Among them, in terms of equipment use and maintenance, the leakage problem can be solved through the following measures: (1) Reduce the frequency of vibration and impact. Vibration and shock are common during the operation of equipment, and the harm to the equipment is relatively large, so it is necessary to take reasonable measures to reduce this damage.
The main methods are: ① Install the hydraulic pump properly to reduce the impact force as much as possible. ②Install a damping device to reduce the destructive force of reversing impact as much as possible. ③Install equipment to absorb impact and reduce damage. ④ Increase the utilization rate of pipe clamps to greatly enhance the vibration resistance of the hydraulic system. ⑤ Reduce the occurrence of resonance phenomena as much as possible.
(2) Select reasonable sealing components and create a perfect sealing structure. Mainly choose from the following aspects: ① It has interference and automatic compensation functions. ② It is wear-resistant, corrosion-resistant and can withstand high temperatures, and is not easily aged. ③The mechanism is easy to install and use, and its integrity is ensured as much as possible.
(3) Reasonably control the working oil temperature. For hydraulic systems, mineral oil is generally used as the working medium, so it is generally controlled between 35 ℃ ~ 45 ℃. The working effect at this time is the best. In addition, it is necessary to control not only the oil temperature but also the oil rise. This can be achieved through the following methods: ① Control the heat sources, coordinate the pressures between them, and reduce the probability of overflow and heat loss. ②Use bypass circulation to reduce oil temperature.
(4) Choose hydraulic oil with good quality. When selecting hydraulic oil, mainly consider the following aspects: ① Have good viscosity and viscosity-temperature properties. ②Good lubrication performance and high oil film strength. ③Good chemical stability. ④Outstanding rust resistance. ⑤Does not affect the use of sealing materials. ⑥The ignition point is relatively high.
(5) ensures that the system is not contaminated and the cleanliness meets certain requirements. ① When replacing components, be sure to avoid contamination from the external environment. ②Continuously expand the filtration area and use a combination of multiple filtration methods to process the filtrate. ③ Filter the new oil several times to make it meet certain standards before adding it to the tank. ④Promptly and effectively handle worn components.
(6) Do a good job in maintaining the hydraulic system: ① Regularly check the connection of the firmware to avoid loosening problems. ②Replace seals according to a certain period. ③Replace the filter element according to a certain period, and effectively check the quality of the oil to ensure the good quality of the oil.
(7) Comprehensively improve the comprehensive quality of management and maintenance personnel. Ensure that the quality of maintenance and overhaul meets requirements: ① Cultivate specialized engineering and technical personnel and manage equipment through them. ② Strengthen the professional and technical literacy of staff and use them to maintain the hydraulic system. ③Continuously strengthen training and education to comprehensively improve the ability of maintenance personnel to prevent and handle accidents. ④ Strengthen daily training work and enhance their business capabilities.
3 Conclusion
Hydraulic-system leakage is currently very common and difficult to control. It is particularly challenging for steel rolling enterprises because their hydraulic systems are highly complex and technical personnel may lack sufficient specialized knowledge and skills to resolve leakage problems. Nevertheless, enterprises must give the issue adequate attention and develop reasonable, effective solutions to limit the progression of leakage as far as possible, creating the conditions for a thorough and effective resolution.
(Source: Steel Rolling Home)