Overall Hardening of Steel

Overall Hardening of Steel With the rapid development of China’s oil industry, the demand for high-grade steel is growing, and high-grade steel must be quenched, and therefore the study of the overall quenching of steel is very important. China Heavy Machinery Research Institute has developed a “dip quenching + internal spray + spin” and “outside the inner jet shower + spin” two processes, and research and development related to quenching line, and achieved good results. Both quenching process has its own characteristics, outside shower inside jet quenching production line is suitable for oil well pipes, oil casing, drill pipe quenching, more conducive to the overall quenching thin wall steel tube; immersion quenching production line is suitable for wall thickness comparison Great overall hardening high performance thick-walled tube, and its products are mainly used in national defense, nuclear power, oil and gas and automotive industries. Immersion quenching production line Domestic quenching equipment currently used, there are some thick-walled tube defects, such as (1), thick-walled pipe bend easily quenched, straightness, roundness poor, to the subsequent shaping cause difficulties; (2) internal and external pipe can not be quenched, resulting Markov body content is low, uneven hardness; (3) high operating costs, poor security. In response to these deficiencies, the hospital independent research and development, complete sets of manufacturing the world’s first use of “immersion quenching + Rotate + inner spray” quenching of steel pipe wall thickness than 20 mm from the overall immersion quenching quenching quenching production line. The process route is: hardened steel furnace heating equipment → arrival gauge mounted on the lift rapidly rotating means pressing means pressing the support wheel drive steel pipe → around rapidly rotating lifting cylinder to drive the steel frame beam rapid immersion quenching in water → within the spray nozzle toward the interior of the steel pipe injection → quenching end, within the spray stop → about lifting cylinder will rise steel frame beams → scroll to stop feeding device at the feeding device by a block-by-turn to the root of the empty water pipe bracket → Empty water means raising one end of the pipe were lifted further blow compressed air quenching water → water → stepping conveyor pipe inside the pipe gradually transported to the feed rollers → complete hardening steel. This immersion quenching quenching unit for the first time using the “immersion quenching + Rotate + inner spray” new technology for large diameter, thick-walled tube overall quenching solve the large diameter thick-walled pipe bend quenching, quenching impervious technical problems; We achieved the following significant results: (1) Due to the overall level of the water pipe, high-speed rotation, multi-point auxiliary support, so that greatly improved straightness of steel, less than 2 mm / m, meet the requirements of the product. (2) using the rotation function within a mobile spray nozzle, reducing the pipe ovality head conducive pipe sizing. (3) With move quenching within quenching process more flexible, more uniform mechanical properties of the steel, after quenching martensite conversion rate of over 90%, even 95%, the hardness and the thickness direction of the full-length steel pipe error of ≤3 HRC. “Spray + outside shower + inner spin” quenching process. This process is relatively thin wall thickness for the pipe. Hardened steel furnace heated to about 1000 ℃, the feed roller to the position to be expected, the feeding device to lift steel flip it onto a slow rotation means rotating support wheels, the pressure mounted on the spray rack rapid tightening means pressing pipe, the rotary drive means rapidly rotating rapidly rotating steel pipe, steel pipe is located directly above the outer surface of the pouring tube to a uniform outer pipe sprinkler, while the spray means installed in the pipe end of the pipe wall to the spray head. Thus the inner and outer surfaces of the steel pipe have been uniform quenching. Post time: Aug-01-2023