Precautions for steel bar welding process construction
29 Feb 2020
1. Before operation, check whether all tools, electric welders, power switches and circuits are good, whether the metal casing is safely and reliably grounded, whether the inlet and outlet wires have a complete protective cover, and whether the inlet and outlet ends are welded with copper joint welding heads. 2. Each welding machine should have a dedicated power control switch and a secondary protection device. It is strictly forbidden to replace other fuses with fuses, and cut off the power supply after completion. 3. The steel bars are all machined and bent according to the design size and shape, the steel bar processing site is hardened, and a rainproof shed is set up. 4. The rebar batching card must be approved by the technical supervisor before the material is allowed to open. The rebars that have been formed are listed in the order of the drawing numbers and stacked neatly. The rust prevention measures shall be taken at the storage site of the rebar. 5. Clean the surface oil stai...
Key points of construction technology of steel bar welding
22 Feb 2020
In the construction of modern buildings, the welding of steel bars is widely used. Common welding methods for steel bars include flash butt welding, arc welding, and electroslag pressure welding. The welding quality of steel bars is related to the weldability of the steel and the welding process. This article briefly discusses the construction technical points of steel bar welding. Welding process The welding process includes arc initiation, stabilizing arc, electroslag, and top pressure. Before welding, the rust in the end of the steel bar should be removed within about 120mm, the clamp should be clamped on the lower steel bar, and the upper steel bar should be straightened. Hold firmly in the moving electrode and fill the flux box with flux. When manual electroslag electric pressure welding is used, the direct arc initiation method can be used. First, the upper and lower steel bars are contacted. After the welding power is turned on, the upper steel bar is lifted by 2 to 4 mm immedia...
Detailed explanation of welding materials used for gas welding and gas cutting!
14 Feb 2020
Gas welding and gas cutting are welding and cutting of metal materials by using the heat released by the mixed combustion of combustible gas and combustion-supporting gas as a heat source. There are many types of combustible gases, such as acetylene, hydrogen, natural gas, and liquefied petroleum gas (mainly propane). At present, the most common application is acetylene gas, followed by propane. Welding materials for gas welding and gas cutting Oxygen: Oxygen is a combustion-supporting gas in gas welding and gas cutting. Oxygen cannot burn itself, but it can help other combustible materials burn. Air separation is commonly used in the industry to produce oxygen. The oxygen used for gas welding and gas cutting is divided into two grades according to purity: the first grade purity is not less than 99.2%; the second grade purity is not less than 98.5%. Oxygen can be supplied in a human oxygen cylinder, or it can be piped. The former is flexible and convenient; the latter is safe and stabl...
Safety precautions for spot welding process
10 Feb 2020
(1) The foot switch of the welding machine should have a solid protective cover to prevent accidental operation. (2) The operating point shall be provided with a baffle to prevent the working sparks from splashing. (3) Welders should wear flat-light protective glasses when welding. (4) The place where the welding machine is placed should be kept dry, and the ground should be paved with anti-skid plates. (5) After the welding work is completed, the power supply should be cut off. The cooling water switch should be extended for 10s and then turned off. When the temperature is low, the accumulated water in the waterway should be excluded to prevent freezing.
Factors affecting welding operation process and welding quality
25 Jan 2020
The surface of the workpiece must be cleaned before welding. The common cleaning therapy is pickling, which means pickling in heated sulfuric acid with a concentration of 10% and then washing in hot water. The specific welding process is as follows: (1) Feed the workpiece joint between the upper and lower electrodes of the spot welder and clamp it; (2) Apply electricity to heat the contact surfaces of the two workpieces and locally melt them to form nuggets; (3) Maintain the pressure after the power is turned off, so that the nugget is cooled and solidified under the pressure to form a solder joint; (4) Remove the pressure and take out the workpiece. The main influencing factors of welding quality are welding current and energizing time, electrode pressure and shunt. 1. Welding current and energizing time According to the size of the welding current and the length of the current, spot welding can be divided into two types: hard and soft. A specification that passes a large current in a...
Spot welding is a resistance welding method
19 Jan 2020
Spot welding is a resistance welding method in which a welding piece is assembled into an overlap joint and is pressed between two electrodes, and the base metal is melted by resistance heat to form a welding point. Spot welding is mainly used in the following areas: 1. Lamination of sheet metal stamping parts, such as car cabs, cabins, fish scale sieves for harvesters, etc. 2. Sheet and profile steel structures and skin structures, such as side walls and roofs of trailers, trailer decks, combine harvester hoppers, etc. 3. Screen and space structure and cross reinforcement. During spot welding, the weldment becomes a lap joint and is pressed between the two electrodes. Its main characteristics are as follows: 1. During the spot welding, the heating time of the connection area is short and the welding speed is fast. 2. Spot welding only consumes electric energy, no filler material or flux, gas, etc. are needed. 3. Spot welding quality is mainly guaranteed by spot welding machines. Simpl...