Introduction to the application of hot-rolled straight seam steel pipes and high-frequency straight seam steel pipes
Posted by BAOWI STEEL MANUFACTURING CO.,LTD on May 17th, 2024
The manufacturer of hot-rolled straight seam steel pipes provides commonly used ultrasonic detection methods for the transverse cracks in the welds produced during the production of thick-walled straight seam submerged arc welded steel pipes for offshore platforms, such as oblique parallel scanning with reinforcement welds, Parallel scanning after removing the weld reinforcement, cross scanning with dual probes across the weld and parallel scanning of the weld with reinforcement. The detection effects of several scanning methods on transverse cracks in welds are compared. The results show that using a shear wave oblique probe with a 9x9K1 (45°) small element to conduct parallel scanning of welds with reinforcement can accurately detect the welds. Transverse cracks. Finally, the repair measures for transverse crack defects are given.
Scope of application of hot-rolled straight seam steel pipes. This product is widely used in medium and low pressure fluid transportation pipelines, gas pipelines, gas pipelines, water supply pipelines, sewage treatment pipelines, air conditioning pipelines, fire protection pipelines, construction projects, chemical engineering, petroleum pipeline engineering, heating Heating engineering and equipment engineering are among the "Ninth Five-Year Plan" high promotion projects and "Torch" plan projects in the past two years, which are suitable for the petroleum and gas industry. Water supply and drainage engineering, chemical industry, electric power industry, agricultural irrigation, and urban construction. It can also be used for gas transmission pipelines, and can be used as structural pipes for piling, bridges, docks, roads, etc. After the two edges of the Gaojie straight seam steel pipe blank are heated to the welding temperature, under the operation of the kneading roller, the individual metal grains are formed to penetrate and crystallize with each other, and finally form a strong weld. If the pinching force is too small, the number of constituent crystals will be small, the strength peak of the weld metal will be low, and cracking will occur after being stressed; if the kneading force is too large, the molten metal will be extruded out of the weld, Not only does it reduce the strength of the weld, but it also causes a large amount of internal and external thorns to form, resulting in defects such as welding seams.
1. The high frequency sensor of high frequency straight seam steel pipe should be as close as possible to the position of the control roller. If it is felt that the distance between the weld and the control roller is far, the effective heating time will be longer, the heat affected zone will be wider, and the strength of the weld will be reduced; on the contrary, the edge of the weld will be insufficiently heated and the molding will be poor after operation.
2. The strip steel is fed into the welded pipe unit. After being rolled by multiple rollers, the strip steel is gradually rolled up to form a circular tube blank with open gaps. Adjust the reduction amount of the kneading roller so that the weld gap is kept within 1 ~3 sister and make both ends of the welding port flush.
3. The welding temperature of high-frequency straight seam steel pipe is affected by the high-frequency eddy current thermal power. According to the formula, the high-frequency eddy current thermal power is affected by the current frequency. The eddy current thermal power is proportional to the square of the current stirring excitation frequency.
In direct proportion; and the current driving frequency is affected by the driving voltage, current, capacitance, and inductance. 4. The exciting frequency of high-speed straight seam steel pipe is in direct proportion to the square root of the capacitance and inductance in the excitation circuit, and approximately inversely proportional to the square root of the voltage and current. Just change the capacitance, inductance or voltage and current in the circuit. Change the frequency of stirring excitation, and then achieve the method of learning to control the welding temperature. For low carbon steel, the welding temperature is controlled at 1250~1460℃, which can meet the welding penetration requirements of pipe wall thickness of 3~5 mm. In addition, the welding temperature can also be achieved by adjusting the welding speed.
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www.baowi-steel.com
