Abstract: The roll system and support roll bearing of plate mill in Shaogang are unstable and prone to failure, which seriously affects production. Through on-line temperature and grease lubrication detection, monitoring and control improvement, the fault is eliminated, and the rolling system, support roll bearings and bearing lubrication reliability are improved.

Key words: Bearings; Temperature; Bearing lubrication; On-line monitoring

0 Preface

Baosteel Group Guangdong Shaoguan Iron and Steel Co., LTD. (hereinafter referred to as "Shaosteel") medium plate 2500mm four-high reversing mill rolling speed of ±0 ~ 2.1 ~ 4.1m/sec. In the process of production rolling, the support roller bearing generates a lot of friction heat in the relative operation of high speed and heavy load. Although there is lubricating grease in the bearing seat, the bearing temperature will inevitably rise, and the upper and lower support roller bearings have no temperature and grease lubrication online monitoring device (system). After reaching a certain temperature (80 ~ 90 ℃), the bearing will be stuck and locked, resulting in the scrap of the bearing and support roller seat and the breaking of the work roller and support roller. In the process of production rolling, the same plate difference and different plate difference are caused, and the rolled parts run off in the rolling process, scrape the frame, and collide with the equipment such as the front of the mill, the back push bed and the roller table. As a result, the cost of bearing spare parts is as high as 300,000 to 400,000 yuan /a, which brings serious losses to production. In order to control the bearing temperature, lubrication and rolling parts in the rolling process and eliminate the fault, it is necessary to carry out on-line detection, monitoring and control improvement on the bearing temperature and grease lubrication.

1 Improve methods and measures

The assembly of the upper and lower back-up rolls and the installation positions in the mill yard of the 2500mm four-high reversing mill, as well as the damage of the back-up roll bearing and bearing seat are analyzed as follows:

1) The installation of temperature detection and grease lubrication installation holes can be realized by setting up temperature detection and grease filling installation holes on the tapered bearing end cover and support roll base on the rolling mill and the lower supporting roll, as shown in Figure 1.

2) Select the appropriate position on the end cover of taper bearing and support roller seat on the off-line maintenance mill, drill holes and tap thread teeth according to the specifications and dimensions of the selected temperature detector, oil injection pipe connection and other equipment, and the hole depth must reach the bearing surface and lubrication point. Install temperature detector with pipe thread, oil inlet filling joint, pipeline and waterproof, high temperature protection, protection and treatment devices.

3) By connecting with the production site temperature detection, data display device, monitoring computer, intelligent centralized lubrication system computer networking and intelligent centralized lubrication oil injection system, the upper and lower support roller bearing temperature and oil injection online detection, monitoring, intelligent centralized oil injection control can be realized, as shown in Figure 1.

2 Temperature detection, monitoring, intelligent centralized lubrication system and control principle

1) The monitoring temperature is set at 0 ~ 85℃, and the alarm temperature is set at 55℃. Selection: flameproof platinum thermal resistance /WZPK2-288\L=150\ 0-200℃ type, for the field testing equipment.

2) According to the temperature control technical conditions and field vibration, ambient temperature difference, ambient air and many other factors, choose: intelligent digital display control transmitter /XMB5026S/0-200℃ type monitoring instrument, measurement control period of 10 s.

3) Monitoring system: JGCW-H1 wireless data acquisition management system of Zhongyuan Optoelectronic Measurement and Control Technology Company is selected.

4) Network: internal LAN of the board process.

5) Oil injection system: ZDRH-2000 intelligent centralized lubrication system is selected.

6) Working principle of system control.

The wireless data acquisition management system is composed of field detection instrument, data logger, wireless data concentrator, management center server and user PC.

Through the detection element, the field instrument transmits the collected temperature signal of the support roller bearing to the data recorder with the current signal of 4 ~ 20 m A, and the data recorder sends the data to the wireless data concentrator through the wireless network, and the wireless data concentrator receives the wireless data and sends it to the management center server through serial communication. The management center server will then collect the data for database storage and management. By installing the wireless monitoring client software, the user PC can invoke data from the management center server on the LAN, query the data time curve, and perform comparative analysis. In this way, the device status can be monitored.

In normal operation, the wireless monitoring client software on the PC monitors the running status of the device in real time through graphs and data tables. When the equipment is slightly abnormal, the management center server calculates and judges and sends an alarm or emergency stop signal to the abnormal situation through the monitoring screen. Remind relevant personnel to take measures to carry out on-site detection, inspection, oil replenishment, and deal with anomalies.

When the bearing temperature is abnormal and exceeds the set temperature value (55 ° C), the monitoring screen sends an alarm signal, prompting the spot inspection personnel and operating personnel to carry out spot inspection, inspection, manual refueling, and take corresponding treatment measures to protect the support roller, bearing and bearing seat.

The wireless data monitoring system sends out the overtemperature alarm signal and sends the control signal to the intelligent centralized lubrication system to realize the online automatic filling of lubricating grease for the support roller bearing and reduce the bearing friction heat.

The intelligent centralized lubrication system adopts PLC automatic control, which is realized through the system program setting: during normal operation, the system is started according to the cycle and cycle time set by the "back-up roll bearing seat grease Standard", and each solenoid valve is electrically activated in turn to feed oil point by point, and the amount of oil is controlled at each point by setting the power time of each electromagnetic reversing valve. Under abnormal circumstances, when the intelligent centralized lubrication system receives the support roller bearing request refueling signal, the PLC control program executes the support roller bearing abnormal refueling operation.

3 Check Maintenance

The environment around the bearing seat of the upper and lower support rolls of the rolling mill is harsh, and the joints, pipelines, lines and plugs of temperature detection and grease filling are easy to be eroded and covered by oxygen reconditioning, oil pollution, roll cooling water, high-pressure water in front of the machine, high-temperature water and steam. Peripheral equipment maintenance, daily roll change operation is easy to be damaged by collision, resulting in wrong signals. Therefore, it is necessary to carry out daily spot inspection, cleaning and maintenance of temperature detection, grease filling joints, pipelines, lines and plug parts to ensure that they are intact and normal.

4 Effects

After the improvement, the effect of on-line temperature detection, monitoring, protection and controllability of the upper and lower support roller bearings of the 2500mm four-high reversing mill is achieved, and the on-line intelligent centralized lubrication of support roller bearings is realized. It provides reliable technical support for spot check, inspection, fixed repair, set refueling cycle and filling grease index. Effectively eliminate the equipment failure caused by the lack of lubrication grease caused by the support roller, work roller, support roller bearing seat scrap, to ensure the normal operation of the equipment.