At present, there are more and more types of straight seam steel pipes. With the rapid development of continuous strip rolling production and the advancement of welding and inspection technology, the weld seams continue to improve, the varieties and specifications of welded steel pipes are increasing, and the steel products are also increasing. The specification of steel is 5.5-250mm. Among them: 5.5-25 mm small round steel is mostly supplied in bundles of straight strips, which are often used as steel bars, bolts and various mechanical parts; round steel larger than 25 mm is mainly used for manufacturing mechanical parts or seamless steel pipe billets.
The correct operation of straight seam steel pipe can refer to the following steps:
1. When the straight seam steel pipe is hung and lifted, the wire rope is not allowed to be pulled obliquely to prevent the wire rope from falling out of the groove.
2. Pay attention during operation to ensure personal safety and equipment.
3. Frequently check the switches at the front and back of the trolley, and whether the switch with the maximum lifting limit of the hook is good and sensitive.
4. Lubricating points such as gears, sprockets, chains, ropes, etc. should be refueled regularly.
5. When operating the cantilever crane, it is necessary to cooperate closely with the hanger and obey the command of the hanger.
6. The hook should be fully hung with coils.
7. The wire rope should be replaced when 10% of its strands are broken.
8. Frequently check whether the hook lifting brake is good and sensitive.
9. When hoisting the steel coil, the straight seam steel pipe should be raised and lowered lightly, and the operation should be stable, accurate and light.
Straight seam steel pipe welding skills:
1. Check whether the specifications of welding wire and flux are correct according to the welding process regulations, and prevent welding accidents caused by wrong use of welding wire and flux.
2. Supervise the welding environment. When the welding environment is not good (the temperature is lower than 0°C and the relative humidity is greater than 90%), corresponding measures should be taken before welding.
3. Before pre-welding, check the groove size, including gaps, blunt edges, angles and gaps, etc., to see if they meet the process requirements.
4. Whether the welding current, welding voltage, welding speed and other process parameters selected in the submerged arc automatic internal and external welding process are correct.
5. Supervise welding personnel to make full use of the length of the arc strike plate at the end of the steel pipe during submerged arc automatic internal and external welding, and strengthen the use efficiency of the arc strike plate during internal and external welding, which helps to improve pipe end welding.
6. Supervise whether the welding personnel have cleaned up the slag first, whether the joints have been processed, and whether there is oil, rust, slag, water, paint and other dirt on the groove.
Acceptance method of straight seam steel pipe:
1. The inspection and acceptance of straight seam steel pipes shall be carried out by the technical supervision department of the supplier.
2. The supplier guarantees that the delivery of straight seam steel pipes complies with the provisions of the corresponding product standards. The buyer has the right to inspect and accept the products 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 provisions of the corresponding product standards.
4. The inspection items, sampling quantity, sampling location and test method of straight seam steel pipe shall be in accordance with the provisions of the corresponding product standards.
5. In the test results of straight seam steel pipes, when a certain item does not meet the requirements of the product standard, the unqualified ones should be picked out, and double the number of samples should be randomly taken from the same batch of straight seam steel pipes, and the unqualified items should be checked. recheck.
ERW high-frequency straight seam steel pipe adopts hot-rolled coil as raw material, and the uniform wall thickness can be controlled at about ±0.2mm. goods and other advantages. In recent years, various gas pipeline network projects and gas companies have widely used ERW steel pipes as the main steel pipes of urban pipeline networks. At present, ERW high-frequency straight seam steel pipe accounts for 60% of the world's steel pipe usage ratio. Straight seam steel pipe refers to a welded steel pipe with one weld in the longitudinal direction of 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 welds, and the angle between the welds is 180 degrees. The welding seam requires the same technical parameters of the straight seam steel pipe as the same welding seam.
According to the production process, it is divided into: ERW high frequency straight seam steel pipe, JCOE straight seam steel pipe, rolled straight seam steel pipe. Straight seam steel pipe is a general term for high-frequency straight seam, submerged arc straight seam, electric welding straight seam, pipeline straight seam and other production process products. The high-frequency straight seam steel pipe adopts the skin effect of high-frequency current to generate high temperature at both ends of the steel plate in a short period of time, and is extruded and fused together by external force, which is a real base metal butt joint without welding rod. In Hebei, straight seam steel pipes often refer to double-sided submerged arc straight seam steel pipes produced by JCOE. JCOE cold forming process is adopted. The welding seams use welding wire and arc submerged with particle flux at the same time, so it is named submerged arc straight seam steel pipes.