In recent years, Sinopec has implemented the quality of gasoline and diesel oil, which has promoted the market demand for the hydrogenation reactor, the core equipment of the transformation project. China has always followed the market pattern, constantly innovated manufacturing technology, and undertaken most of the domestic hydrogenation reactors with forged and welded structures.
In the production of processing hydrogen barrel forgings, in order to prevent the quenching and tempering deformation deviation after rough machining from not meeting the finish machining size, a certain heat treatment allowance is usually left for the wall thickness direction of barrel forgings during the process preparation. On the basis of ensuring that the barrel section forgings are fully hardened, compared with the original rough machining allowance, the heat treatment allowance of this forging blank quenching and tempering process decreases by about 30mm in the direction of the barrel section wall thickness, reducing the forging ingot from the original 220T to 202T, saving 18T molten steel and greatly reducing the production cost.
At the same time, compared with the original rough machining quality, the rough machining quality saves the rough machining production process of forgings, that is, it shortens the cross workshop transportation, rough machining and other production cycles, saves the rough machining process searching, enables the forgings to be processed to the finish machining size, greatly saves the cold machining labor consumption and mechanical equipment occupation, and speeds up the production progress of the cold machining process; Forging heat treatment of hydrogenation gas joints in the same workshop is convenient for production organization and coordination, and effectively improves productivity.
Production process:
Steelmaking - forging - post fracture heat treatment - rough machining - ultrasonic flaw detection - welding thermal buffer block - performance heat treatment - performance inspection - such as blank warehouse after processing and flaw detection.
Quenching and Tempering Process of Barrel Forging Blank
Improvement process: After the forging process is completed, heat treatment is required after forging. Due to the progress of smelting technology, the hydrogen content and impurity elements in steel have been effectively controlled. Therefore, the main purpose of post forging heat treatment is to adjust and refine the grain, so as to make organizational preparation for performance heat treatment and ultrasonic flaw detection after subsequent rough machining.
Due to the large size of forgings, it is easy to produce grain thickness and mixed crystals in the forging process. Coarse crystals and mixed crystals will reduce the strength, plasticity and impact toughness, especially the impact toughness. To prevent the above problems, the annealing process is used for heat treatment.
As the improved process cancels the roughing process, the preparatory heat treatment process is adjusted. After heat treatment of forgings, heat buffer blocks shall be welded according to technical conditions, and then performance heat treatment shall be carried out for forgings.
Compared with the rough machining+quality regulation process of cylinder forgings, we adopt the method of moving up and down when the forgings are water-cooled. This is mainly due to the formation of thick oxide skin after high temperature forging and heat treatment after forging. After entering the water, due to the high temperature, a layer of steam bubbles forms on the surface of the forging, and the rough oxide skin hinders the rise and overflow of the bubbles, which is equivalent to a layer of insulation layer on the surface of the forging blank.
Therefore, in the cooling stage of blank quality regulation, we took the measure of moving the forging up and down immediately after the water entering the forging, so as to make the bubbles overflow quickly, so as to achieve the purpose of rapid cooling of the forging. At the same time, adjust the performance heat treatment process.