Specimen preparation before welding using 15CrMoG seamless, specifications for φ325 × 25 with angle grinder before welding the grinding inside and outside the groove and the groove edges and 50mm to the exposed metallic luster, then clean with acetone. Specimens fixed horizontal position, counterpart gap 4mm, using GTAW circumferentially uniform spot-six, are each tack length should not be less than 20mm. Welding Table 2 provides baked. 2.3 welding parameters before welding to be preheated preheating temperature preferably from 150 ℃. The use of oxygen - acetylene flame for heating the specimen, first determining temperature temperature pen rough surface of the specimen (in handwriting color change speed estimate), the last point temperature was measured by using a semiconductor measuring point must select at least three When welding, the first layer GTAW base, in order to avoid the back of the weld seam produced at Yang depression, within the filler wire method using thick-walled seamless wire feed, that the wire is fed through a gap from the inner tube counterparts . The remaining layers using SMAW, a total of 6 layers of solder, a solder layer on each bead. When connected to a large thick-walled seamless steel pipe, interlayer temperature should be no lower than 150 ℃ in thick-walled seamless steel tubes, welded to prevent the interruption caused by the cooling of the specimen shall be two welders welding alternating operation, immediately after welding Insulation measures taken to slow cooling. Program Ⅰ weld heat treatment using 2.4 weld specimens should be local temperature tempering after welding. Heat treatment process: heating rate of 200 ℃ / h, rose to 715 ℃ temperature for 1 hour and 15 minutes, the cooling rate of 100 ℃ / h, down to 300 ℃ after air cooling. Specific use JL-4 type crawler-type electric heater (1146 × 310) surrounding the weld special thick-walled seamless steel tubes, with a layer of silicate cotton insulation, insulation thickness 50mm, temperature control DJK-A type electric heater automatic temperature control device. Production and manufacturing methods boiler tubes |; ① general boiler pipe temperature below 450 ℃, homemade pipe is mainly used on the 10th, the 20th of hot-rolled carbon steel cold drawn pipe or tube manufacturing. ② high-pressure boiler pipe often in high temperature and high pressure conditions, the use of the tube under the effect of high temperature flue gas and water vapor, would oxidation and corrosion. Requirements durable steel with high strength, high oxidation resistance, and good organizational stability. Uses: ① general boiler water wall tube is mainly used to make pipes, boiling water pipe, superheated steam pipes, superheated steam locomotive boiler tubes, and large, small pipe and brick arch tubes. ② high pressure boiler steel is mainly used to manufacture high-pressure and ultra-high pressure boiler superheater tubes, reheater tube, airway, the main steam pipe. Large thick-walled seamless steel pipe industry _ virtues (certified) _ thick-walled seamless steel pipe by virtue Liaocheng Industry Co., Ltd. Liaocheng virtue Pipe Co., Ltd. (www.meidegc.com) (www.meidegc.com) (www.mdwfg.com) (www.mdggc.com) Shandong Liaocheng, steel leaders, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. In virtue tube industry leadership with the staff warmly welcome all inquiries negotiations to create the virtues of Industry a better future.