The Typical Application of Calcium Sulfonate Complex Greases in Steel Mills By: Li Jiwei, Cheng Shutian, Zhao Wei, Wu Baojie Tianjin Branch, SINOPEC Lubricant CO., LTD.
Abstract The production process in steel mills is pretty long with numerous equipment exposed to a variety of working conditions that require different greases. For example, some equipment exposed to large amounts of water for extended periods of time require grease with excellent water resistance properties. In the areas of high ambient temperature and long re-lubricating intervals, the grease requires thermal and oxidative stability. In alkaline environments, the grease needs excellent protective properties. Calcium sulfonate complex grease (CSCG), with its comprehensive and excellent properties, is increasingly popular in the steel mill industry. Certain properties of CSCG can be further improved by formulation and process design to meet requirements of grease on different equipment in steel industries. Typical data for several CSCGs will be presented in this paper. In addition, their application performance in the equipment in wet, rusty, high temperature, alkaline environments and open gears will also be discussed. Introduction Machines and equipment in the steel industry are generally operated in the conditions of high temperature, high load, vast water spraying and continuous working. The typical working conditions are • High temperature - The temperature at the of bottom of an iron-making blast furnace is 1300-1500 °C, and at its top the temperature is 400-600 °C. The temperature of a secondary cooling area of continuous casting is 800-900 °C, and the billet temperature during hot rolling is 850-1000 °C. The high temperature radiates and conducts heat to lubricated parts. • Water spraying - A large amount of water spray occurs on billet steel on roller bearings, rollers and bearings of hot rolling, on pinch rolls and guided rolls in secondary cooling areas of continuous casting. High pressure water is used to remove phosphorus from other equipment. • Dust – There are great amounts of dust, mainly the smoke,
iron slag, steel slag and iron scale generated due to fuel burning. • Loads - Heavy loading and impact loads are applied during the working process to working roll bearings of rolling mills, shearing machines, rocking shear of continuous casting equipment, bearings of coiling machines, exposed gears and other equipment. • Operations - Continuous operations at steel enterprises are common. Production equipment can be operated stably for long periods of time. In order to meet the requirement for high reliability of metallurgical equipment, grease must withstand the test of these working conditions. In recent years, CSCG started to attract the attention of the grease industry by its comprehensive, excellent performance such as excellent high temperature performance, mechanical stability, colloidal stability, extreme pressure and anti-wear performance, water resistance and excellent corrosion resistance. There are a number of reports showing applications in industrial facilities under severe lubricating conditions at steel mills1-3. Certain properties of CSCG can be further improved by formulation and process design to meet requirements for grease on different equipment in the steel industry. Typical data of several CSCGs will be presented in this paper. Application of CSCG in the Presence of Water Rolling mills and continuous casters equipment consume large amounts of grease in the steel industry, under wet working conditions. Refer to Table 1 for typical data for CSCG for wet applications. A hot rolling mill is the key equipment in a hot rolling plant, and bearings in rolling mills are just like joints in humans. Today, the steel industry is committed to continuous production. If the rolling mill bearings burn, it will cause a huge economic loss or downtime. Therefore, it is very important to monitor the performance of grease used in a rolling mill’s bearings. Performance and trends of grease can be learned through the analysis and tests of samples.
- 32 VOLUME 82, NUMBER 1
