Push the limits! Jiugang successfully rolled 105mm ultra-thick carbon structural steel plate
Jiugang has pushed the design limit of wide and thick plates from 100mm to 105mm, so the riveting and welding capabilities of ultra-thick steel plates above 50mm are finally no longer a headache. Once this board is produced, customers who need energy equipment and marine engineering products will no longer have to look at imported products.
What is the difficulty with 105mm thick plate?
6 to 100mm is the design range of Jiugang's wide and thick lines. If it is more than 5 mm, the rolling mill reduction, heating furnace temperature, and straightening torque must be recalculated. "Technicians say that as the thickness increases, the risk of internal cracks and delamination directly doubles.
The Jiayuguan factory technical team has been repeatedly adjusting and adjusting the rolling pass model since the second quarter of this year, and then locked the reduction amount to the millimeter-level accuracy range, and also kept the internal and external temperature difference during heating within 15 degrees. Only in this way can the temperature of the billet entering the rolling mill be stable.
How to build quality traceability
For products such as ultra-thick plates, the real worry is not that there is no way to roll it out, but that if an accident occurs, it is difficult to find the root cause of the problem.
Therefore, the company Jiuquan Iron and Steel has developed a traceability system covering the entire process. This system allows the information of each furnace of molten steel, every parameter in the rolling process, and all curve data in the cooling stage to be adjusted and controlled through one-click operation.
Equipped with an abnormality correction mechanism, when a deviation occurs in a certain process, the next process will automatically make up for it. In order to solve the problems of surface oxide scale intrusion and scratches, high-pressure water descaling and manual re-inspection are used before finishing rolling, which basically blocks the inflow path of related defects.
Actual measurement of mechanical indicators
We took the samples to a third-party testing agency for testing. The results showed that the yield strength, tensile strength, elongation after break, and impact energy at room temperature all met the standards. In terms of the flatness of the plate shape, the error per meter did not exceed 2 mm, and the surface quality was rated as excellent.
After observation, it was found that the density of the metallographic structure is good, and no cracks such as delamination were found. Therefore, when riveting and welding thick plates with a thickness of more than 50mm are processed downstream, there is no need to worry about the inherent defects of the material itself. During the operation, the processing allowance of the material can be pressed very tightly, thus saving a required finishing process.
What are you most concerned about in downstream riveting welding?
When riveting welding thick plates over 50mm, the most feared thing is post-weld deformation and interlayer stress. This plate has very good welding performance, and the impact energy has also reached the standard. In a low-temperature environment, the riveted welded nodes will not be brittle and fracture, which indeed brings very good news to wind power towers and offshore platforms.
The performance of dimensional accuracy has been stabilized, which means that the customer can save a finishing process, which saves real money and precious time. Because the order delivery cycle for customized energy equipment was shortened by one week, the difference in profit was tens of thousands of yuan.
How to enter the high value-added market
There are only a handful of manufacturers in China that can stably roll 105mm wide and thick plates with carbon structures. When customers choose materials, the first thing they ask is whether they can produce this thickness stably. This time, JISCO has put the answer directly on the table.
Large-scale panels are developing in the direction of high-end and customization. Customers now not only look at the price per ton of goods, but also value the comprehensive performance that the product can provide upon delivery. Jiuquan Iron and Steel entered the market relying on this type of product, and was able to handle subsequent demands for special ingredients as well as small and multi-batch orders.
What's left for the next step?
The situation now is that 105mm is just the beginning. The team is trying to conduct tests with a thickness of 120 mm, and even explore situations thicker than this value. At the same time, process models are gradually being transferred and adjusted in the direction of alloy steel.
According to the plan, Jiugang Company plans to complete relevant work in the coming period. Specifically, it will complete the certification of multi-specification ultra-thick plate products before the first quarter of next year.
Upgrading specifications is not just as simple as increasing the thickness by a few millimeters. The depreciation cost of the equipment needs to be re-considered, the energy consumption during the cooling process must be included in the calculation, and the loss of the straightening rollers must also be accounted for one by one.
However, since the significant increase in profit per ton of high value-added products is large enough, it is fully capable of covering these new costs. After calculating the balance of accounts from the perspective of overall economic benefits, the results are feasible.
When our factory is doing riveting and welding of plates with a thickness of more than 50 mm, where does it get stuck? Is it a problem with the material specifications or the processing technology? Everyone is welcome to talk about the riveting and welding processing capabilities of ultra-thick steel plates above 50mm in the comment area. If you think this statement is useful , the riveting and welding processing capabilities of ultra-thick steel plates above 50mm will break through the limit! Jiugang has successfully rolled 105mm ultra-thick carbon structural steel plates. Please give it a thumbs up for its ability to rivet and weld ultra-thick steel plates over 50mm , or forward it to colleagues you know.
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