Main technological characteristics of geological drilling pipes

Any device or product will have different manufacturing processes during production, and will play different roles in the manufacturing process. For example, the main process flow of geological drilling pipes is as follows: electric arc furnace smelting - secondary refining - billet continuous casting - tube blank rolling - tube blank piercing - rough tube heat treatment - steel pipe cold drawing - finished product heat treatment - steel pipe straightening - acceptance - packaging and warehousing.

Different manufacturing processes are involved in the production of any equipment or product, and they play different roles in the manufacturing process. For example, the main process flow of geological drilling pipes is as follows: electric arc furnace smelting - out-of-furnace refining - billet continuous casting - tube blank rolling - tube blank piercing - rough tube heat treatment - steel pipe cold drawing - finished product heat treatment - steel pipe straightening - acceptance - packaging and warehousing. The manufacturing process seems simple, doesn't it? In practice, however, many precautions and problems await us. Next, let's talk about the main process characteristics of this product.

　　1. Main process: 42MnMo7 steelmaking process:

　　The key to 42MnMo7 smelting is component control. Reducing harmful impurities and gas content is essential to avoid segregation in the cast billets. Therefore, the following requirements are made for the smelting process:

　　(1) During the melting process, pay attention to controlling the oxygen blowing intensity to ensure that the clarified carbon is greater than 0.50% and the endpoint carbon is greater than 0.20%;

　　(2) Due to the large amount of manganese iron added, in order to prevent manganese iron from increasing P and causing P to exceed the standard, the steel tapping P ≤ 0.10% and the steel tapping temperature is greater than 1640℃;

　　(3) Add niobium iron with the steel flow at a recovery rate of 95%;

　　(4) Sling temperature: 1580-1590℃ for the first sling, 1560-1570℃ for subsequent slings.

　　2. Main process of geological drilling pipe: tube blank rolling:

　　42MnMo7 is a medium-carbon bainite series steel with a certain amount of Nb added. The addition of Nb can prevent the growth of austenite primary grains during the heating process of the billet. Considering the dissolution of Nb into austenite and ensuring rolling in the recrystallization zone, the heating temperature is set to 1180-1220℃. The purpose of controlling the final rolling temperature is to refine the grains and prevent the deterioration of the plasticity of the tube blank. A large number of studies have shown that by rolling near the critical temperature of austenite, due to the decrease in deformation temperature, the recrystallization ability of austenite is weak, and the austenite crystals are compressed and elongated. At the same time, defects such as dislocations generated during the deformation process are not easy to disappear, thus providing a large number of nucleation sites, high nucleation rate, and refined grains, resulting in good steel toughness. In the rolling process control, the final rolling temperature is determined as Ar3+(50-100)℃, approximately 820-870℃.

　　3. Main process: tube blank piercing:

　　(1) Billet inspection - shearing - inclined bottom furnace heating - two-roll inclined rolling piercing

　　(2) When heating the tube blank, low-temperature slow heating is used, and the heating and furnace temperature is controlled at 1220-1240℃, the heating time is 50-60min, the rolling rhythm is controlled at 3 pieces/min, and the number of billets in the furnace is kept above 150.

　　4. Main process: cold drawing:

　　After the rough tube undergoes stress relief annealing, pickling, and lubrication, it is placed for 2-3 days to remove hydrogen embrittlement, and then drawn into finished products on a 75t chain cold drawing machine.

　　Are the main process characteristics of these geological drilling pipes not very understandable? The theoretical knowledge is indeed a bit difficult to understand, but if its role is utilized, it will be a very important role. Of course, in the cold drawing process of this product, try to avoid problems such as cracks, cracks, and breakage, then the success rate of the refining results will be very high.