At present, there are more and more types of straight seam steel pipes. With the rapid development of strip steel continuous rolling production and the advancement of welding and inspection technology, the welds are constantly improving, the varieties and specifications of welded steel pipes are increasing, and the steel materials are also increasing. The specifications of hot-rolled round steel are 5.5-250 mm. Among them: 5.5-25 mm small round steel is mostly supplied in bundles of straight bars, often used as steel bars, bolts, and various mechanical parts; round steel larger than 25 mm is mainly used to manufacture mechanical parts or seamless steel pipe blanks.
First, the correct operation of straight seam steel pipes can refer to the following steps:
1. When hanging and lifting straight seam steel pipes, the wire rope is not allowed to be pulled obliquely to prevent the wire rope from slipping out of the groove.
2. Pay attention during operation to ensure personnel and equipment.
3. Check the switches before and after the trolley frequently, and whether the switches with the maximum limit of hook rise are easy to use and sensitive.
4. Lubrication points such as gears, sprockets, chains, and ropes of straight seam steel pipes should be refueled regularly.
5. Operate the cantilever crane in close cooperation with the crane operator and follow the crane command.
6. The hook should be fully loaded with coils.
7. When 10% of the wire rope is broken, it should be replaced.
8. Check whether the lifting brake of the hook is good and sensitive.
9. When lifting the steel coil with the straight seam steel pipe, it should be lifted and lowered gently, and the operation should be stable, accurate, and light.
Second, straight seam steel pipe welding skills:
1. According to the welding process regulations, check whether the specifications of the welding wire and flux are correct to prevent welding accidents caused by the wrong use of welding wire and flux.
2. Supervise the welding environment. When the welding environment is not good (temperature below 0℃, relative humidity greater than 90%), take corresponding measures before welding.
3. Before pre-welding, check the groove size, including gap, blunt edge, angle, and misalignment, to see if they meet the process requirements.
4. Whether the process parameters such as welding current, welding voltage, and welding speed selected in the process of submerged arc automatic internal and external welding are correct.
5. Supervise the welding personnel to make full use of the length of the arc-starting plate at the end of the steel pipe during submerged arc automatic internal and external welding, and enhance the efficiency of the arc-starting plate during internal and external welding, which will help improve the welding of the pipe end.
6. Supervise whether the welding personnel clean up the slag first, whether the joints have been processed, and whether there is oil, rust, slag, water, paint, and other dirt on the grooves during repair welding.
Third, the acceptance method of straight seam steel pipes:
1. The inspection and acceptance of straight seam steel pipes should be carried out by the supplier’s technical supervision department.
2. The supplier guarantees that the delivered straight seam steel pipes meet the requirements of the corresponding product standards. The buyer has the right to inspect and accept according to the corresponding product standards.
3. Straight-seam steel pipes should be submitted for acceptance in batches, and the batching rules should comply with the requirements of the corresponding product standards.
4. The inspection items, sampling quantity, sampling location, and test methods of straight seam steel pipes shall be by the provisions of the corresponding product standards.
5. If a certain item of the straight seam steel pipe test result does not meet the requirements of the product standard, the unqualified ones should be picked out, and double the number of samples from the same batch of straight seam steel pipes should be randomly selected for retesting of the unqualified items.
ERW high-frequency straight seam steel pipe uses hot-rolled coil as raw material, and the wall thickness can be uniformly controlled at about ±0.2mm. The two ends of the steel pipe are trimmed and grooved according to the APl standard or GB/T9711.1 standard, and the length is fixed. Delivery has the advantages of such. In recent years, various gas pipeline network projects and gas companies have widely adopted ERW steel pipes as the main steel pipes for urban pipelines. At present, ERW high-frequency straight seam steel pipes account for 60% of the world’s steel pipe usage. Straight seam steel pipe refers to a welded steel pipe with a longitudinal weld seam on the pipe body. GB/9711.1 stipulates that when the diameter is greater than 914.4, the straight seam steel pipe can have two straight weld seams, and the weld angle is 180 degrees. The weld seam requires the same technical parameters as the straight seam steel pipe with the same weld seam. According to the production process, it can be divided into: ERW high-frequency straight seam steel pipe, JCOE straight seam steel pipe, and rolled straight seam steel pipe. Straight seam steel pipe is a general term for products produced by high-frequency straight seam, submerged arc straight seam, electric welding straight seam, pipeline straight seam, and other production processes. High-frequency straight seam steel pipe uses the skin effect of high-frequency current to generate high temperature at both ends of the steel plate in a short time and squeeze and melt together by external force. It is a true welding rod-free base material butt joint. Straight seam steel pipe in Hebei often refers to the double-sided submerged arc straight seam steel pipe produced by JCOE. It adopts the JCOE cold forming process, uses welding wire for the weld, and uses granular flux to submerge the arc at the same time, so it is named submerged arc straight seam steel pipe.
Post time: Jan-02-2025