The improvement of the heat treatment method of Q345B ms seamless pipe is accompanied by the increase of the quenching temperature, and the quenching strength is gradually increased. When the quenching temperature is lower than 1200°C, the secondary hardening condition at the time of quenching is not significant. If the quenching temperature is higher than this temperature, the cementite melts more, the martensitic aluminum alloy increases, and the austenite is further strengthened. During quenching, more disperse cementite is precipitated from the austenite, and the second hard bottom is only shown. Increase the quenching temperature to avoid the transformation from austenite to troostite throughout the die application, thereby reducing mechanical stress. The traditional quenching process is changed from 1-time quenching to 3-time quenching, so that the low-strength residual martensite in the raw material after quenching is fully transformed into high-toughness 2-time austenite, which improves the physical properties of the mold.
Q345B seamless pipe quenching: 550 ℃ furnace box type resistance furnace heating, to avoid mold core carburization, heat preservation for 40 minutes; then heat up to 1150 ℃, heat preservation for 120 minutes. Then let the oil cool to room temperature. Q345B seamless pipe quenching: quenching for 3 times, each heating temperature is 660 ℃, and the temperature is kept for 90 minutes. The service life of the mold shell solved by this heat treatment method can reach 4500 times, which reduces the cost of the mold shell and improves the production efficiency. The above plus sign pushes the martensitic computer motherboard strips to crystallize and cause a decrease in ductility. The decrease in the quenching rate leads to a gradual increase in the overall width of the martensitic plate structure. The requirements of the natural environment are reduced, and delamination greatly reduces the effect of steel on thickness specifications. Including alignment, deep processing and inspection, etc., to ensure that the Q345B seamless pipe can maintain high quality when leaving the factory.
Q345B seamless pipe is a kind of steam pipeline, which belongs to the seamless pipe category. Q345B seamless pipes are often in a high temperature and high pressure state throughout the application process. Under the action of high temperature smoke and water vapor, the pipeline is oxidized and corroded by air. It is stipulated that seamless steel pipes have high physical compressive strength, high oxidation and corrosion resistance, and excellent mechanical reliability.
Q345B seamless pipes are mainly used in the production of heating surface pipes, reheater pipes, conduits and main steam pipes for high pressure and high pressure heating furnaces. Q345B seamless pipe is a kind of steam pipe, which belongs to the seamless pipe category. The production method is the same as the seamless steel pipe Q345B seamless pipe, but there are strict regulations on the steel grades used for the production of seamless steel pipes.
