China's metallurgical industry, construction steel to meet the increasing demand in recent years were introduced from abroad dozens of high-speed wire rod production line, the discharge port speeds ranging from 63 ~ 100m / s, annual, mostly in 60 × 104 ~ 100 × between 104t. Due to the special nature of the work of high speed wire rod mill, equipped with a bearing on the proposed more stringent requirements. In this paper, high-speed wire rod mill bearings (hereinafter referred to as high-speed wire rod mill bearings) operating characteristics, structure, design and manufacture of critical points, etc. for a brief introduction.
1. Performance requirements
1.1 high reliability
High-speed wire rod production line most notable feature is the continuous rolling mill high reliability. Due to the high yields of high-speed wire rod production line requirements within the prescribed inspection period, as a key element of the rolling bearing have higher reliability than the average mill bearings. If the result of bearing failure will lead to the entire production line shutdown, which is the manufacturer tolerated. So in the design, manufacture of high speed wire rod mill bearings, should ensure the reliability of its continuous work under high speed conditions.
1.2 wear
High-speed wire rod mill bearing wear degree stronger, able to adapt to high-speed rotation of the workplace. Example: A high-speed wire rod production line, the outlet line speed 63m / s, exit rolling mill working diameter of 330mm, the bearing operating speed of 3650r / min, long-term operation at high speed, heavy load bearing wear will It is a severe test. This requires that for bearing must have wear-resistant requirements.
1.3 long fatigue life
High-speed wire rod mill bearing fatigue life longer. Under normal circumstances, the use of high-speed wire rod mill bearings provided from abroad for three years (half the time due to unloading the roll assembly and maintenance, refurbishment, the actual working time is one and a half), so the user requirements made bearings can be used at least two years.
1.4 Impact toughness is better
High-speed wire rod mill bearing impact toughness is better, especially roughing mill bearings used, the billets rolled into the bar of the process, a large impact load. Therefore, high speed wire rod mill bearings operate at high speed, high impact status should not rupture occurred.
In summary, the operating characteristics of high-speed wire rod mill bearing is stable and reliable work continuously at high speed, high impact status, and have a longer fatigue life.
2 forms bearing structure
High-speed wire rod mill bearings, four-row tapered roller bearings and double row cylindrical roller bearings two son. In general, coarse, medium mill using four-row tapered roller bearings, finishing mill double row cylindrical roller bearings, horizontal mill and hammer mill using the same type of lead bearing.
Whether four-row tapered roller bearings or double row cylindrical roller bearings, the basic structure is similar to this traditional mill bearing, but various parts of the design fully consider the lubrication and cooling issues, namely the inner ring, an outer ring, separated ring (for four tapered roller bearings concerned), cage, rollers (for double row cylindrical roller bearings concerned) has opened a lot of slots, holes and so on. Thus, slots, holes are formed lubrication, cooling channels and bearing, roll on the channel to form a reliable lubrication and cooling systems, coupled with a good seal, so that the bearing can be stabilized at high pressure state to run.
Although various vendors provide high-speed wire rod mill bearing design style is different, but all have one thing in common, that is, the wall thickness of the inner ring relative to the same specifications of the ordinary bearing little thick, the outer ring is relatively thinner.
3. Bearing Design Method
First, according to the functioning of the respective lines bearing service life, failure status and user requirements, appropriate adjustments to the main parameters, allowing designers to achieve more satisfactory results.
Secondly, reasonably determine the technical conditions, based on the measured results of similar products and consider the bearing of the specific working conditions, reasonable technical requirements.