Understand the steel connection mode and what are the requirements?
The welding methods of steel bars include resistance welding, flash butt welding, electroslag pressure welding, gas pressure welding and arc welding. The welding methods, tools and welded steel bars are different, as follows:
The welding methods of steel bars include resistance welding, flash butt welding, electroslag pressure welding, gas pressure welding and arc welding. The welding methods, tools and welded steel bars are different, as follows:
1. Flash butt welding. The two sections of welded steel bars are contacted by a butt welding machine. After the steel bars are heated to a certain temperature and softened by a low voltage and strong current, the steel bars are pressed and forged axially to form a butt welding joint and extend the steel bars along the axial direction. According to the butt welding process, flash butt welding is divided into continuous flash welding and flash-preheating-flash welding, the latter is used for welding large-diameter steel bars. This kind of welding is used for prestressed reinforcement.
2. Arc welding. Arc welder is used to produce high temperature arc between the welding rod and the welding part, so that the welding rod and the welding part within the arc combustion range are melted, and the joint or weld is formed after solidification. The joint types of steel bar arc welding are: lap joint (single-sided weld or double-sided weld), bond joint (single-sided weld or double-sided weld), sectioning joint (flat welding or vertical welding).
3. Electroslag pressure welding. Put a small piece of conductive agent (steel wire ball, electrode rod, etc.) between the upper and lower welded steel bars, install a medicine box and fill with welding agent, connect the electric circuit with AC welding machine for arc ignition combustion, after forming slag pool, steel bar melting and arc stabilizing for a certain period of time, at the same time of power failure, use manual pressure mechanism for pressure top forging to eliminate slag inclusion and air bubbles and form joints. This kind of welding is mostly used for the extension of vertical steel bars in cast-in-place reinforced concrete structural members.
4. Resistance spot welding. The upper and lower electrodes of the spot welding machine contact the crossed steel bars and turn on the current. The resistance at the contact point of the crossed steel bars is relatively large, and the heat generated by the current melts the steel bars. At the same time, the electrodes are pressurized to weld the steel bars. It is used for cross connection of steel bars such as welded steel mesh and steel skeleton.
5. Steel bar gas pressure welding. The end of the steel bar is heated to a plastic state (temperature is about 1320~1340 ℃) by a certain proportion of oxygen (purity ≥ 98.5, bottled working pressure is less than 5~10kg/cm2) flame, and the steel bar is welded together by heating and pressurizing, and finally a pressure of more than 3000kg/cm2 is applied.
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