Because seamless steel pipes work under high temperature and high pressure conditions for a long time, the material will undergo stress relaxation, plastic deformation and ductility reduction, initial structure changes, and corrosion.
The seamless steel pipe used as a heating furnace should have:
(1) Sufficient long-term compressive strength.
(2) Sufficient plastic deformation capacity.
(3) Minimal aging tendency and hot ductility.
(4) High oxidation resistance, fly ash resistance, gas corrosion resistance at high temperature, steam and intergranular corrosion characteristics.
(5) Excellent mechanical reliability and excellent performance.
The production and processing technology of seamless steel pipes varies with the grade of steel. Taking ferritic chromium molybdenum vanadium steel as an example, the production and processing characteristics of seamless steel pipes are:
(1) The finished rolled tube should be peeled, and the peeled amount is generally 5 mm.
(2) Because the steel is hard, the finishing tube should be cut or sawed by co2 laser.
(3) Because the heat transfer of chrome-molybdenum-vanadium steel is lower than that of carbon steel, the heating rate should be slower, the heating temperature is 1120-1180°C, and the perforation temperature is 1100-1160°C.
(4) This kind of steel has good plastic deformation and low deformation resistance in the range of 1000-1100 ° C, so the perforation performance is good, and the deformation parameters can be selected according to low-carbon steel or carbon steel.
(5) After rolling, the seamless steel pipe should be quenched and quenched. The quenching temperature is 950-980°C, the quenching temperature is 730-750°C, and the heat insulation time is 2-3h.
(6) The standard tolerance of seamless steel pipes is relatively strict to ensure professional butt welding. The length of the pipe should be as long as possible to reduce the number of welds.
The seamless steel pipe used as a heating furnace should have:
(1) Sufficient long-term compressive strength.
(2) Sufficient plastic deformation capacity.
(3) Minimal aging tendency and hot ductility.
(4) High oxidation resistance, fly ash resistance, gas corrosion resistance at high temperature, steam and intergranular corrosion characteristics.
(5) Excellent mechanical reliability and excellent performance.
The production and processing technology of seamless steel pipes varies with the grade of steel. Taking ferritic chromium molybdenum vanadium steel as an example, the production and processing characteristics of seamless steel pipes are:
(1) The finished rolled tube should be peeled, and the peeled amount is generally 5 mm.
(2) Because the steel is hard, the finishing tube should be cut or sawed by co2 laser.
(3) Because the heat transfer of chrome-molybdenum-vanadium steel is lower than that of carbon steel, the heating rate should be slower, the heating temperature is 1120-1180°C, and the perforation temperature is 1100-1160°C.
(4) This kind of steel has good plastic deformation and low deformation resistance in the range of 1000-1100 ° C, so the perforation performance is good, and the deformation parameters can be selected according to low-carbon steel or carbon steel.
(5) After rolling, the seamless steel pipe should be quenched and quenched. The quenching temperature is 950-980°C, the quenching temperature is 730-750°C, and the heat insulation time is 2-3h.
(6) The standard tolerance of seamless steel pipes is relatively strict to ensure professional butt welding. The length of the pipe should be as long as possible to reduce the number of welds.
