750 cold rolling mill bearing roller bearing abnormal damage analysis

750 cold rolling mill bearing roller bearing abnormal damage analysis - 2018 09 - 22 lei duan strong ( Rolling mill bearing) Foreword: in 750 four high rolling mill bearing roller bearing plant FCDP80112410 rolling element and the corresponding to the outer ring often occurs in a short period of time the damaged craze, to the use of bearing and assembly work to bring inconvenience. Aiming at this problem, the first rolling element and the outer ring of bearing damage inspection analysis, for example: roller, hardness testing according to JB/T8881-1 2011 'rolling bearing parts carburizing heat treatment technical conditions' standard, the roller sample hardness testing, test results are shown in table 1 indicate: roller has been used. 2, non-metallic inclusion examination basis GB3203 - 82 the carburizing bearing steel technical conditions and YB - 68 'chromium bearing steel technical conditions', non-metallic inclusions on roller sample inspection. Test results are shown in table 2. 3, the organization of quenching tempering and carbide test according to JB/T8881 - mesh 2011 'rolling bearing parts carburizing heat treatment technical conditions' standard, the roller sample quenching tempering organization and carbide network test, test results are shown in table 3. 4, rolling body element content in table 4. According to GB/T3203 - 1982 standard for carburizing steel bearing technical conditions, the roller sample test content, test results are shown in table 4. 5, according to JB/T8881 - the inspection results 2011 'rolling bearing parts carburizing heat treatment technical conditions' standard, hardness testing was carried out on the roller sample, sample roller hardness accord with a standard to ask. On the basis of GB3203 - 82 the carburizing bearing steel technical conditions and YB - 68 'chromium bearing steel technical conditions', non-metallic inclusion of roller sample inspection, non-metallic inclusions roller sample qualified. According to JB/T8881 - 2011 'rolling bearing parts carburizing heat treatment technical conditions' standard, the roller sample quenching tempering organization and carbide network test, roller sample microstructure is eligible. So beyond bearing under the premise of their own reasons for the plant's bearing assembly site tracking all the time, and the scene to participate in the installation, disassembly and maintenance work to find the main reason for the damage of bearing abnormal: one, the structure of the roll system assembly two FCDP bearings is separable, assembling way and strong interchangeability of four row cylindrical roller bearings, the outer ring and rolling body installation within the bearing housing, the inner ring interference installed on the roll of the roll diameter, again through the whole bearing precise locating bearing lock on the roll, thus form a bearing box, a combination of roll and bearing assembly, because of its bearing capacity is strong, manufacturing high accuracy, after installation to facilitate rapid and can be removed parts swap features, are often chosen for rolling mill bearing roller bearing, radial load bearing. But because of the rolling element contact with inside and outside the circle to linear linear, it itself does not have bearing performance, so any wrong when bearing is running will cause abnormal hidden danger, to the use of the bearing is required to install precision is higher. Three, bearing damage form as shown in the assembly structure, often occurs near the side of the roll rolling element bearing abnormal face wear and breakage, outer cracking phenomenon. Four comprehensive analysis, damage phenomenon above damage phenomenon, and the damage location, can clear judgment bearing force exists serious phenomenon of partial load, close to the roll list of rolling element bearing edge stress concentration, the more stress. At the same time also leads to the formation of a corresponding outer edge stress. Factors lead to the phenomenon of partial load of the bearings is mainly a cross or tilted in roll system, such as: mill screwdown failure, caused by the difference of roll gap bigger; To drive the roller box at the bottom of the side and operation side bearing arc plate size difference is big, lead to the transmission side and operation side bearing misalignment; Wear and memorial arch bearing clearance, rolling in the scissors, etc. , which will lead to the bearing stress of asymmetry. Five, the corresponding measures bearing assemblies and roll system installation: bearing box size, aperture, taper shape should be in the standard range, such as: bearing box should have enough stiffness requirement, because of the rolling mill bearing outer ring wall thickness is very thin, it must have a valid rigid support to bear the heavy rolling load. Hole deformation of bearing is bearing box strength is not enough or serious will make bearing outer ring early fatigue fracture. Bearing box and frame arch fixed point, with the center line of the bearing seat or symmetry, lest produce moment of couple, load bearing so see chart. Try to reduce the tolerance clearance in bearing box and frame arch to slow the transmission is not smooth or the impact on the bearing steel. Recommended clearance < 0. 45mm。 Adjust good lining board, avoid or reduce the roll axis is not parallel to produce the production of the cross roll Angle, and reduce the axial impact load. Mill balance system is stable and reliable, balance is consistent, otherwise it will produce bearing skewed or reverse, increased bearing load uneven and impact. Bearing itself: through appropriate adjustment bearing radial clearance, slow adjustment of inner ring aperture edge uneven phenomenon, do the bevel, reduce stress circle on the side of the bearing with roller diameter roll system under the condition of bad sealing structure, the bearing roller box under their own add seal, prevent emulsion particles into the bearing inside and the outside world.