The problems encountered in the production of steel structure and their solutions

1. The chemical composition of steel structure is related to the machinability, toughness and durability of steel. It is mainly associated with the content of carbon and some alloying elements.

2, process performance refers to the weldability and processability, which also has some connection with the carbon content.

3, the appearance of steel structure production deviation, steel surface should be free of bubbles, cracks, inclusions, if there is also to be timely removal. And its depression degree, not greater than the steel thickness of the deviation value. There are rusts on the surface of steel that affect its appearance, and it should be treated.

4, in mechanical cutting, the use of equipment to cut, such as shears, sawing machines and so on.

5. Hot forming of steel structure refers to heating steel to a certain temperature before processing. The method is suitable for forming, bending and correcting parts that cannot be machined at room temperature. Steel with carbon content beyond the range of low carbon steel is generally not hot working.

6. Cold forming is carried out at room temperature. The material will produce the desired long-term deformation because the external force exceeds the yield strength of the material, or some part of the material will be separated from the material as required because the external force exceeds the strength of the material.

The positioning axis of the foundation and the elevation of the supporting steel cylinder exceed the allowable deviation value. The reasons are as follows: errors and deviations exist in basic survey control network, basic survey wiring and elevation finding. Foundation formwork support is not firm, pouring concrete material is too high, concrete vibration impact, so that the formwork displacement, resulting in deviation of the baseline. Or the use of steel ruler, theodolite, level without calibration, there is error. Or the construction of wrong drawings, wrong axis, without strict inspection. Or foundation support surface without two wipe pressure, leveling, concrete settlement shrinkage subsidence. Or the embedded steel plate (or support) did not take fixed measures. As the foundation positioning axis and support surface are out of tolerance, the column installation axis and support elevation will appear out of tolerance, which will affect the quality of the whole structure installation project.

Preventive measures: 1) The precision of the basic measurement control network, the instruments and measuring tools used for basic measurement lay-off and leveling should be accurate. Before use, it should be checked or verified by the measurement department, and timely adjustment should be made when problems are found to prevent errors or cumulative errors, resulting in the axis and elevation exceeding the allowable deviation.

2) Foundation template support should be firm, should have enough strength and stiffness. When pouring concrete and vibrating, to prevent the impact of the template, displacement. In the process of pouring concrete, should be fixed time with measuring tool or suspension line inspection positioning axis, elevation, if found deviation, should stop pouring, vibrating, through reinforcement adjustment after elimination. Before concrete final setting, the surface of foundation concrete should be rubbed and levelled twice. The embedded steel plate or support should be adjusted by the secondary elevation, levelness, and ensure that the concrete at the bottom is dense. The base supporting column steel plate or support shall be provided with necessary fixtures to ensure correct position and elevation.