There are more and more places around us that need steel structure engineering. For some of its methods, our operators still need to understand more clearly. What are the selection methods of openings in steel structure engineering?
Drilling is the preferred method for drilling steel structures. Punching is allowed when it is proved that the quality, thickness and hole diameter of some materials and will not cause brittleness after punching. Drilling is carried out on machines such as drilling rigs, which can drill steel structural members (parts) of any thickness. The advantages of drilling are less damage to the bolt hole wall and better quality.
In the processing and manufacturing of steel structures, punching is generally only used for punching non-circular holes and thin plate holes, and the hole diameter of punching must be greater than the plate thickness. Punching is allowed for all ordinary steel structures with thickness less than 5mm, and punching is allowed for secondary structures with thickness less than 12mm. No welding (groove shape) shall be conducted on the punched hole later, unless it is proved that the material still maintains considerable toughness after punching. In general, when reaming, the hole must be 3 mm smaller than the specified diameter.
Third, the machining accuracy of steel structure is higher. When there are many layers of and plates with the same kind of and holes, the hole can be expanded by drilling forming holes or pre drilling smaller holes during assembly. When the plate stack is less than 5 layers, the diameter of the pre drilled hole is less than the first level nominal diameter (3), and when the plate stack is greater than 5 layers, it is less than the second level nominal diameter (6).
When drilling four or holes, a flat drill is usually used. When drilling holes that cannot be penetrated, a sharp drill is used. When the plate stack is thick, the diameter is large or the material strength is high, a group of bits that can reduce the cutting force should be used to facilitate chip removal and reduce bit wear.
Five long holes can be processed by drilling at both ends and oxygen cutting in the middle, but the length of the hole must be greater than twice the diameter of the hole.
When drilling six steel structures, high-strength bolt holes shall be drilled.
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