Steel structure welding detail information as following :
1. Welding method
Common Steel Structure welding methods are arc welding, including manual arc welding, automatic or semi-automatic arc welding, and gas shielded welding.
Manual arc welding is the most commonly used steel structure welding method , and its equipment is simple and flexible. However, the labor conditions are poor, the production efficiency is lower than the automatic or semi-automatic welding, and the variability of the weld quality is large, which depends to some extent on the technical level of the welder.
The weld quality of the automatic welding is stable, the internal defects of the weld are less, the plasticity is good, the impact toughness is good, and it is suitable for welding long direct welds. Semi-automatic welding is suitable for welding curves or welds of any shape due to manual operation. Automatic and semi-automatic welding shall be carried out with welding wire and flux compatible with the main metal. The steel structure welding wire shall comply with the requirements of national standards, and the flux shall be determined according to the welding process requirements.
Gas shielded welding uses inert gas (or CO2) gas as a protective medium for the arc to isolate the molten metal from the air to keep the welding process stable. Gas shielded arc heating is concentrated, the welding speed is fast, and the penetration depth is large, so the weld strength is higher than that of manual welding. It has good plasticity and corrosion resistance and is suitable for welding thick steel plates.
2. Weld form
The weld joint form can be divided into four forms, such as butt joint, overlap, T-joint and corner joint, according to the mutual position between the connected members. The welds used for these joints are in two basic forms: butt welds and fillet welds. In the specific application, it should be selected according to the force of the connection, combined with the manufacturing, installation and welding conditions.
3. Weld construction
The butt welding force is direct, smooth, and has no significant stress concentration, so the force performance is good, and it is suitable for the connection of components subjected to static and dynamic loads. However, due to the high quality requirements of the butt welds, the welding gap between the weldments is strict, and it is generally used in factory-made joints.
The form of fillet weld: the fillet weld can be divided into a side fillet weld parallel to the direction of force action and a front fillet weld perpendicular to the direction of force acting obliquely to the direction of force action, depending on the length direction and the direction of action of the external force. Diagonal fillet welds and perimeter welds.
The fillet weld cross-section is divided into ordinary, flat and deep-melt. The proportion of the common-type welding foot is 1:1, which is similar to the isosceles right-angled triangle. The transmission line is bent more severely, so the stress concentration is serious. For the structure directly bearing the dynamic load, in order to make the transmission force smooth, the front fillet weld should adopt a flat slope type with a ratio of two weld angles of 1:1.5 (long side and inner force direction), and the side fillet weld should adopt a ratio of 1 :1 deep-melting type.