Common Quality Objections And Solutions For H Beam Products

1. Bending defects of section steel of h beam

1. Bending up and down

Causes: (1) During the rolling process, the extension of the web and flange does not match; (2) The cooling of the upper and lower webs is uneven; (3) The straightening reduction is small, resulting in unstraightening of the bend; (4) ) The straightening temperature is high, and the upper web is bent back due to the sawing cooling water during sawing.

Control measures: (1) Strengthen process training, increase the adjustment level of employees, and enhance employees' quality awareness; (2) Use downtime to calibrate the zero position of the straightening machine to achieve precise adjustment. (3) Reasonably control the straightening temperature, and straighten at ≤100°C; (4) Use the reduction reasonably.

2. Side bending of h beam

Causes: (1) During the rolling process, the extension of the flanges on both sides does not match (that is, the side bending of the straightened incoming material is large); (2) The thickness of the profiled billet itself is inconsistent; (3) The straightening axial reduction is small.

Control measures: (1) Reasonably control the reduction of the vertical roll to match the flanges on both sides; (2) Increase the axial force of the straightening machine as much as possible to straighten the side bending of the section steel; (3) Ensure straightening of the vertical roll normal use.

3. Web bending of h beam

Causes: (1) Due to high final rolling temperature and too much water used during hot saw cutting, the web is bent and appears at the kerf of the hot saw; (2) Web and flange Mismatched extensions, mostly on rolled heads.

Control measures: (1) Use a reasonable rolling chart according to different materials to ensure that the web flange extension matches; (2) Reduce the final rolling temperature and reasonably control the cooling water volume of the hot saw.

2. Center deviation of h beam

Causes: (1) The billet is out of square or the pass pattern of the billet is unreasonable, and the cutting is not centered, resulting in the difference in the amount of metal on the flanges on both sides; (2) The axial misalignment of the billet or tandem; The height of the bridge and the rolling mill is not suitable (that is, the rolling line is not in a straight line); (4) The rolling mill, archway, and bearing housing are severely worn, resulting in uneven rolls.

Control measures: 1. Arrange box-shaped holes in billet rolling as far as possible to eliminate the influence of billet off-square; 2. When rolling starts or there is downtime, observe the axial condition of the rolling mill in time; 3. Affect the rolls of the rolling mill and archway Balanced components set the maintenance cycle to ensure the precision of the rolling mill; 4. Reasonably control the height of guides, bridges, etc. to ensure the level of the rolling line.

3. Thickness tolerance of h beam

Causes: (1) The unequal thickness of the flange (corner to corner) is caused by the misalignment when the upper and lower rolls of the universal frame are calibrated; (2) The unequal thickness of the flange (side to side) is It is caused by the different reductions of the vertical rolls on both sides; (3) The poor precision of the rolling mill leads to large fluctuations in the thickness of the head, middle and tail.

Control measures: (1) The unequal thickness of the flange (corner to corner) can be compensated by adjusting the offset of the vertical roller; (2) The unequal thickness of the flange (side to side) can be avoided by properly adjusting the frame ; (3) Formulate equipment maintenance system to ensure the precision of rolling mill.

4. Welding (winter welding R angle cracking) cracking of h beam

Causes: (1) The temperature difference between the web and the flange is large, and there is stress inside, and the stress releases during welding, resulting in welding cracks; (2) The steel material does not match the electrode material; (3) The user cuts and welds in the wrong order in winter.

Control measures: (1) Use ultra-fast cooling or flange cooling water after the tandem machine to reduce the temperature difference between the web and flange and reduce internal stress; (2) Use reasonable welding rods for welding steel; (3) When cutting in winter, first Cut the web and then the flange; when welding in winter, weld the flange first and then the web.