The railway frame group took the development and application of the spring frame gold material

Smelting and smelting electric furnace smelting to ensure the purity of steel and grain size greater than 5, in the smelting should be fully deoxidized, degassed, remove inclusions. The raw materials for the furnace are required to be clean and dry, consisting of cutting head and high-quality scrap. The tapping temperature is controlled at 16501670, the tapping w(P) is not more than 0.015%, the molten steel is strictly prohibited from peroxidation, w(Cu) is less than 0.20%; the aluminum-manganese iron 2.0kg/t steel and synthetic slag 1415kg/ t steel; the slag is strictly prohibited in the tapping process.

LF furnace refining In order to ensure the stability of the mechanical properties of the steel and the stability and easy operation of the heat treatment process, it is very important to control the narrow range of chemical composition. The control target of the smelting component meets the requirements, and the deoxidation, desulfurization and stirring are strengthened during the operation; Analysis, the sampling temperature should be greater than 1550, and analyze the total aluminum content; the tapping temperature is in the range of 1540-1560, w(S) 0.015%, and the final deoxidation of aluminum is not performed before tapping.

The smelting composition controls the liquidus temperature of the steel to be cast 1482. In order to ensure the quality of the molten steel, the pouring temperature and the pouring and drying system must be strictly controlled. The filling time of the cap is greater than 2/3 of the casting time of the ingot. After demoulding The steel ingots are slowly cooled into the pits in time, and the slow cooling time is more than 24 hours. The surface of the ingots must be strictly inspected and finished.

The billet and the ingot are opened into 75 billet, the heating temperature of the ingot is controlled in the range of 1130-1180, the temperature difference between the yin and the yang is <30, the finishing temperature is 850, and the heating time is 2.5h. After the pickling of the billet, the grinding must be strictly carried out. . The heating temperature of the material is 1000-1060, the heating time is 45min, the temperature difference is allowed to 30, the final rolling temperature is 850, and the steel is strictly subjected to surface quality inspection and finishing.

The quality inspection of steel products was carried out in two batches, and 30 batches of trial production were carried out. The steel ingots were 1144.685t, and the pass rate of steel ingots was 100%. Due to the first production and after delivery, the finished product was reduced to only 76.44. %. Chemical composition statistics The chemical composition of 30 furnace steels can be seen, and the chemical composition can be stably controlled within a narrow range. Performance test for decarburization, 2 low, statistical 60 tensile and decarburization and 90 hardness test results. The results of the low-power test were all qualified, and the grain inspection was above 7 grades. The metallographic structure and inclusions were observed and the tests were all normal.

Surface quality The first batch of steel mainly showed small rolling scratches and folding defects, and some steel dimensional tolerances were too large. This was mainly because the first batch delivery time was only 20 days, and the new hole type system was not controlled. However, the production of the organization is too hasty, and the 13mm specification is the first new opening type, and the new opening type is also produced according to the positive deviation production. In the second batch of 9 furnace steel production, the process control was improved. The 2 batches of 9 furnace steels were all subjected to hot forging inspection. The top forging was all qualified once. The surface quality was better than that of the first batch of 21 furnace steels. Basically, there was no similar problem.

Steel manufacturing process: Cold shearing, medium frequency, electric heating, thermoforming, waste heat quenching, continuous resistance furnace, tempering, surface rust prevention, packaging. Elastic strip processing and forming process: After shearing and cutting, a single low-voltage and high-current medium-frequency induction heating is heated to 920950 (about 3s), and then three-step stamping (the process takes about 7s), then the residual heat quenching, the water quenching temperature is above 830. The quenching tank is continuous. After 30s of the treaty, the water from the quenching pool is continuously discharged into the collecting basket, and then tempered in a continuous mesh belt resistance tempering furnace for 500/40min. After being discharged, the pile is cooled in the basket, and the inspection is qualified. After collecting the dipping paint for packaging. After the heat treatment of the elastic strips, the elastic strips were subjected to sampling inspection, and the 5 million fatigue life, surface hardness, metallographic structure and dimensional inspection of the elastic strips were carried out. All the inspections were qualified once and met the standard requirements, and the users were satisfied.

Summary (1) Through two batches of tests, it shows that Laiwu Steel adopts Germany's imported 50tUHP (EBT) electric furnace slag-free tapping technology + LF furnace using multi-functional synthetic slag refining production of railway springs water quenching spring steel 38Si7, steel is pure, The technology is advanced and reasonable, and the quality is stable. Laiwu Steel has the ability to organize production according to international standards. (2) The steel processing flange is water quenched, which saves resources and is conducive to environmental protection. After the use of the elastic strips, the users have reported good results, and the physical quality of the products has reached the international advanced level, which has improved the foreign exchange earning capacity of Laiwu Steel products. (3) Although the product has completed technical appraisal, from the actual application situation, the current product quality still needs further stability and improvement. On the basis of the first two batches of trial production, Laiwu Steel will strive to improve the appearance quality of products and improve the physical quality of products through better process improvement and better meet the needs of domestic and foreign markets.

Easy to handle and remove; strong and robust at the same time; 

Far more weather resistant.

Easy to handle and remove; strong and robust at the same time; 

Far more weather resistant.

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Temporary Fence,Temporary Chain Link Fence,Temporary Welded Fence ,Galvanized Temporary Fence

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