Fin Tubes----High -frequency spiral fin tube welding procedures
High -frequency spiral fin tube welding procedures a , material cutting steel pipe to the required length ( by drawing ) , with the angle grinder , sandpaper, steel surface rust removal , inspection, adjustment pipe is not straight degrees, each m ≤ 1.0mm, length ≤ 10mm. Second, the high-frequency heating device starts GP.200 preheat frequency induction heating equipment , high frequency induction heating equipment according GP.200 procedures, connected to the cooling water , preheat the filament . Third, adjust the welding machine ( 1 ) mounted on the steel pipe welding machine , steel embedded in the guide wheel , high-frequency electrodes and steel , the steel strip into a contact state , and connected to the cooling water . ( 2 ) for the steel strip and steel electric arc positioned and fixed . Fourth, high-frequency welding procedure specification shown in Table
Specification Material anode current anode current A Ⅱ A Ⅰ gate current gate current A Ⅱ A Ⅰ Low Carbon 7.0 ~ 7.6A 7.0 ~ 7.6A 1.2 ~ 1.6A 1.2 ~ 1.6A 12CrMo 7.2 ~ 7.8A 7.2 ~ 7.8A 1.2 ~ 1.6A 1.2 ~ 1.6A 1Cr18Ni9Ti 7.2 ~ 7.8A 7.2 ~ 7.8A 1.2 ~ 1.6A 1.2 ~ 1.6A seamless adjustment screw rotation speed V , longitudinal feed speed V feed , the spiral fin spacing conforms to the drawings. Note: 1, the welding process operator frequent scraping sound test, check welding quality meets the requirements, do not meet the requirements , you should check does not meet the cause and take measures to resolve it. 2 , self-test : fin pitch deviation ≤ ± 0.2mm, fin angle α ≤ 8 °. V. Test:
1 , visual inspection : a. Fin height tolerance ± 0.75mm. b. between the fins and the steel pipe welds shall be continuous , not crack, not welded or intermittent weld defects such as the sum of the length of the fin should be less than the total length of the weld Ia ≥ 0.90t. c. finned tube nonstraightness : finned tube per meter straightness ≤ 1.0mm, length ≤ 10mm. d. pitch deviation ≤ ± 0.2mm. e. should be perpendicular to the surface of the fin and the tube , fin rake angle α ≤ 8 °. 2 , scraping sound : sound frequencies crisp , consistent sound . 3 , peel the patch test : weld cross section is silver-white , and a stripped traces. 4 , hydrostatic testing : test specification :
Material mild steel pressure MPa time minutes 2 times the design pressure or customer requirements 5 alloy design pressure of 2 times or customer requirements 5 stainless steel design pressure of 2 times or customer requirements 5 to pipe watertight as qualified. Six , monitoring and recording requirements of this process is a special process , the operator must be prepared to monitor and record inspection , monitoring parameters for the anode current A Ⅰ, anode current A Ⅱ, the cathode current A Ⅰ, cathode current A Ⅱ, bumban monitored at least three times ( time interval 2.5 to 3 hours ) .
Key Words: Finned Tube, Fin Tubes, Extruded Fin Tubes, Embedded Fin Tube, L Fin tube, Tubos Aletados