1. 20G material heat treatment system: 900 ~ 930 ℃ normalizing, hot rolling pipe finishing temperature of not less than 900 ℃, can replace the normalizing. 2. 15CrMoG material heat treatment system: 930 ~ 960 ℃ normalizing. 680 ~ 720 ℃ tempering, holding time: cycle furnace is greater than 2h. Continuous furnace is greater than 1h. 3. 12Cr1MoVG material heat treatment system: 980 ~ 1020 ℃ normalizing, holding time by wall thickness per mm 1min, but not less than 20min. 720 ~ 760 ℃ tempering, holding time, cycle furnace is greater than 2h, continuous furnace is greater than 1h, when the wall thickness is greater than 30mm to 40mm, should be forced cooling; when the wall thickness is greater than 40mm, should be quenched and tempered, 990 ℃, tempering temperature of 720 ~ 760 ℃, holding time: cycle furnace is greater than 2h. 4. 1Cr18Ni9 material heat treatment system: solution treatment: solution temperature ≥ 1040 ℃.

Cold drawn steel pipe in the production and processing of the technical requirements are particularly high, cold drawn steel pipe under the action of heat, because the surface of the temperature is relatively high, faster shrinkage, the speed of condensation is relatively fast, in the The process of condensation is more susceptible to stimulation! In order to pursue the high quality of the physical and chemical properties must be cold-drawn steel pipe heat treatment. The faster the cooling rate, the higher the carbon content and the composition of the alloy, the greater the uneven plastic deformation produced by the thermal stress during the cooling process, and the greater the residual stress formed. On the other hand, the steel in the heat treatment process due to changes in the organization that austenite to martensite transformation, due to the increase in specific volume will be accompanied by the expansion of the workpiece volume, the workpiece has changed the various parts, resulting in volume growth is inconsistent and produce tissue stress. The ultimate result of tissue stress changes is the tensile stress of the surface, the compressive stress of the heart, and the opposite of the thermal stress. The size of the tissue stress is related to the cooling rate, shape, chemical composition of the workpiece in the martensitic transformation zone. Cold-drawn steel pipe heat treatment technology is related to the hardened steel pipe hard, the volume of the perfect and the relationship between this technology.

(1) Plasticity (perforation performance). Bearing cold drawn seamless steel pipe at high temperature has good plasticity and perforation performance, but the heating temperature should not be too high, the general control of 1150 ℃ or so, the temperature is too high prone to grain growth (overheating), reducing metal perforation performance. (2) Thermal conductivity. Bearing cold drawn seamless steel pipe thermal conductivity lower than the low carbon steel should be appropriate to control the furnace temperature (especially the heating of large cross-section bearing cold drawn seamless steel pipe billet). (3) Mechanical properties. The tensile strength of the cold drawn seamless steel pipe under normal temperature is much higher than that of C0.3% carbon steel (about doubled), and the hardness is high and the deformation is difficult in cold working. Therefore, spheroidizing annealing is carried out before cold deformation, To improve the plasticity and reduce the hardness, to 1000 ℃ above the difference between the two very little. Bearing cold drawn seamless steel pipe hot rolling is not much difficulty. (4) Deformation resistance. Bearing cold drawn seamless steel pipe has a high deformation resistance (see metal deformation resistance) and the sensitivity of the temperature is greater, the lower the temperature deformation resistance is higher. Hot rolled bearings cold rolled seamless steel pipe to prevent rolling cold steel. The production of bearing cold drawn seamless steel pipe pipe is sometimes limited by the sizing machine and straightening machine capacity, this is because the bearing cold drawn seamless steel pipe wall thickness, coupled with low deformation resistance at low temperature, making the rolling force and straightening force A significant increase. Cold drawn bearing cold drawn seamless steel pipe pulling force than pulling low-carbon steel pipe about 50% higher. The following are the same as the " (5) Wide spread. Bearings cold drawn seamless steel pipe width than carbon steel about 10% to 20%, but in the temperature range of 885 ~ 1195 ℃ change is very small, which gives cold drawn seamless steel pipe production to control the lateral deformation of metal The convenience.

Cold drawn seamless pipe control of rolling and cooling can reduce alloy consumption and reduce production costs, so in the production of seamless steel pipe is being promoted, and the initial formation of online regularization, on-line quenching, online rapid cooling and other processes. 1, Online regularization process On-line regularization is also known as on-line normalizing, is in the hot rolling line after the rolling process, so that the steel pipe get the uniform microstructure of the process in the austenite phase air cooling or forced cooling. The process consists of two phase change processes: 1) The cooling pipe is from 1100 ℃ to 550 ℃ below the steel austenite into ferrite + pearlite; 2) The seamless steel pipe by reheating after cooling, steel in the ferrite + pearlite and into austenite. Through the online regularization, both can make steel uniform, grain refinement; can improve the comprehensive mechanical properties of seamless steel pipe. 2, On-line quenching process 1) Austenitic stainless steel tube Austenitic stainless steel tube on-line quenching, also known as on-line solid solution, is the C element dissolved in austenite to form a single austenite. The solution temperature is generally 1000-1150 ° C. Cooling can be used water, oil, air cooling and so on. 2) Carbon steel, low alloy steel pipe Refers to the use of rolling after the waste heat directly to the water quenching, and then on-line tempering treatment of quenching and tempering heat treatment process. Through this process can greatly save energy. 3, Online rapid cooling process It is based on ultra-fast cooling technology as the core of a new generation of technology. Refers to the use of rolling after the use of rolling heat after the direct heat treatment process is to strengthen the cooling of the austenite after rolling, so that the metal in a very short period of time quickly cooled to near the ferrite phase transition temperature, thus inhibit the austenite grain growth, try to keep the austenite hardening state. On-line rapid cooling in the improvement of seamless steel pipe organization, improve the comprehensive mechanical properties of seamless steel pipe, refine the surface grain, improve the anti-fatigue crack growth ability and so has obvious effect.

Cold drawn steel pipe in the use of air-cooled quenching process, in order to ensure the cooling effect of cold drawn steel pipe, cold drawn steel pipe fan volume should be large enough. And it must ensure that the required cooling rate of cold drawn steel pipe, so the fan should be set up and down the two rows, two or four control, cold drawn steel pipe at any time to adjust the required amount of air or control the profile of the hot and cold caused by uneven The deformation. Because the method of online air cooling now we can master here do not do too much narrative. Cold drawn steel tube early adoption in water cooling quenching process method is used to produce more rules of aluminum rods, etc. However, in this way cold-drawn steel pipe, the process of wearing water due to irregular irregularities, the cold-drawn steel pipe on both sides of the water cut board made more specifications, and can not fully control the flow of water from the gap, so submerged Pull the pipe above the water is not good control.