1.Cutting and cutting 

During cutting and cutting, the width of flange plate is different, which results in the size difference between H-beam and bracket. The upper and lower flange plates of steel beam connected with corbel are staggered by about one plate thickness; there are deep cutting marks at the cutting edge, obvious depression on the plate edge, or deep saw tooth mark, the cutting roughness exceeds the standard, the cutting edge is not vertical, and the splicing is wrong.

2.assemble

During assembly, H steel was welded without assembly jig, which resulted in deviation of H-beam height dimension and web deviation; after butt joint of wing web, weld was not leveled and obvious concave convex was found; light steel web plate was not flat and was not corrected before assembly.

3.welding

In terms of welding, light steel welded H-beam flange plate was spliced after cutting, and the weld was not installed with run-off arc plate, resulting in the weld not full, there were pits on the edge, not fused, and not flush with the base metal; the weld foot size of column foot and bracket was smaller than the design drawing, the phenomenon of fillet weld collapse was serious, the arc stopping point was generally lower than the base metal, and there were many air holes; the weld seam formed by CO2 welding was poor, with different widthAs a result, the height is not consistent, sometimes large or small; manual welding seam is not straight, width is different, undercut phenomenon is serious; spatter of welding slag is not cleaned.

4.drill hole

In terms of drilling, the drawings were not well reviewed in advance, and double rows of holes were opened at the place where the single row of holes was opened. As a result, the holes were left on the components without making up the holes.For example, the H-shaped steel at the connection of column and bracket is double row hole, while the H-beam with the same specification as the secondary beam is a single row hole, but double row holes are opened when opening, which affects the strength and appearance quality after installation.

5.Assembly process

In the process of general assembly, the connection of steel column corbel and H-beam is dislocated from top to bottom, left and right, and the size is not well controlled.

6.Rust removal and painting

Derusting and painting: the rust removal is careless, and the paint does not meet the grade requirements, and the paint will rust and peel off soon; the thickness of the paint film is uneven, the thickness of the sunny surface is generally super thick, up to 250 μ m, but the shady surface is often about 90 μ m (the indoor paint film thickness is specified as 125 μ m); the impurities are not removed before painting, and there are many dirt, uneven and sagging phenomenon.

7.Transportation and storage of components

In the process of transportation and stacking of components, there are no shelved parts to be leveled and stacked. Instead, they are unloaded randomly and stacked disorderly, and even the components are buried in the ditch of the mud pile, causing deformation, bruise and pollution of the components.

8.Component delivery

When the components are delivered from the factory, the center line marks of steel columns and beams are not marked, which is quite common, which brings difficulties to the rectification detection of installation and construction.

9.Wing web splicing

The splicing length of wing web does not meet the requirements.If the splicing length of the flange plate should not be less than 2 times of the width of the flange plate, the splicing weld between the flange plate and the web plate should be staggered by more than 200 mm, and the splicing length of the web plate should not be less than 600 mm.However, the above requirements are often not met.