Analysis of five common failures in steel rolling
- Card steel
Card steel refers to a fault phenomenon in which the rolling stock is stuck on the rolling line due to the influence of the surrounding environment during normal operation, and cannot be rolled in the downstream direction. The main reasons for this are: the size of the incoming rolling stock is too large, the shape is distorted; the amount of this passage is too large; the inlet guide is not correct, too tight, too loose or the rolling body is lost; the exit guide is skewed or inside the guide Foreign objects are left; the temperature of the rolled parts is low; the mechanical and electrical equipment is faulty.
- Rolling roller
The winding roller refers to a rolling failure phenomenon in which the rolled piece is wound on the roll in an unexpected and irregular manner in the circumferential direction of the rolling. The main reason for the occurrence is that the roller diameter difference between the upper and lower rollers is large, resulting in a large upper or lower pressure; the gap between the contact guide device and the roller contact portion is too large; the inlet and outlet guide devices are misplaced; the rolling stock is accidentally entered. The hole type of the outlet guide is not installed.
Slipping generally means that the head of the rolling stock has contacted the roll and sometimes even partially entered the deformation zone, but the rolling piece is ultimately unable to be bitten into the rolling mill to form a normal rolling phenomenon. The main causes are: the material is too large, causing the actual bite angle to exceed the allowable bite angle; in the case of a large bite angle, the cross section of the rolled piece is small, and the pitch of the rolling mill is large, resulting in no reduction of the rolled piece. The rolling line is not correct, and there is resistance to the running of the rolling stock.
- Pull steel
Pulling steel means that during the continuous rolling process, the metal second flow rate of the downstream frame is significantly larger than the metal second flow of the adjacent adjacent frame, and a large tensile stress is generated on the rolled piece, so that the central portion of the rolled piece is reduced or even pulled. A fault phenomenon that breaks.
- Pile steel
Stacking steel means that during the continuous rolling process, the metal second flow rate of the downstream frame is significantly smaller than the metal second flow of the adjacent adjacent frame, and a large amount of metal accumulation occurs between the two frames, which causes the stability of the rolling stock to be destroyed or even caused A failure phenomenon of rolling waste. The reasons for pulling steel and stacking steel are basically the same, mainly in the following aspects: the rolling speed is set incorrectly; the speed does not match the rolling section; the electrical system has fluctuations; the temperature difference of the rolling stock is too large.
For the above processing of rolling faults, it is first necessary to analyze the specific causes of the faults and take targeted measures. Sometimes a fault occurs, which may be affected by several factors at the same time. It is necessary to pay attention to comprehensive analysis, and avoid unilateral and subjective judgment.
The torsion of the rolling stock of the non-twisted turning steel pass during the rolling process should be avoided as it is an unstable factor and has an adverse effect on the rolling process and product quality. The main reasons for this phenomenon are: the wrong roller causes the upper and lower rolling grooves to be unaligned, so that the rolling parts naturally generate force couples; when the rolling stock of the last turning steel pass enters the frame rolling mill, the torsion turning angle is too large or too small. The guide is not properly installed, such as the inclination of the beam installation, the non-parallel to the axis of the roll, and the misalignment of the rolling guide; the fullness of the rolled piece in the hole type is insufficient or overfilled; .