5.4 Furnace Body
Ⅰ Dominant Items
5.4.1 In case of welding for assembly of furnace body，the WPQ shall be carried out with report，based on which the welding procedure and the operation instruction for welding shall be determined or prepared.
Quantity to be checked:100%.
Inspection method:Check WPQ report and the operation instruction for welding.
5.4.2 The internal quality of butt welds from the assembly of furnace body shall comply with the requirement of the design technical document，or that of GradeⅢof weld quality grading criteria of Construction and Acceptance Code for Welding Work of Field Equipment and Industrial Pipeline（GB 50236）in case of no requirement in the above document.
Quantity to be checked:100%.
Inspection method:Check the ultrasonic inspection record.
5.4.3 The appearance quantity of butt welds in case of furnace body assembly shall meet the requirement of the design technical document，or that of Appendix E of the Code in case of no requirement in the above document.
Quantity to be checked:100%.
Inspection method:Observe or check with a magnifier.
5.4.4 The postweld heat treatment of butt welds in case of furnace body assembly shall meet the requirement of the design technical document，or that of Appendix F of the Code in case of no requirement in the above document.
Quantity to be checked:100%.
Inspection method:Observe and check the record of heat treatment.
5.4.5 The water-cooled furnace mouth must be subject to hydrostatic test and flushing test according to the requirement of the design technical document.If no requirement in the document，the following requirements shall be complied with:booster its pressure to the test pressure which shall be 1.5 times of the working pressure and hold for 10 min，and then lower it to the working pressure and hold for 30 min，and check whether there is pressure fall or leakage.The test shall be qualified in case of no pressure fall or leakage.In case of flushing test，the water shall be able to flow in and out smoothly and freely for at least 24 h，without any leakage.
Quantity to be checked:100%.
Inspection method:Observe，and check the records for pressure test and flushing test.
5.4.6 The connection device for furnace body and backing ring shall be installed according to the requirement of the design technical document.
Quantity to be checked:100%.
Inspection method:Observe，actually measure，and check the inspection record.
Ⅱ General Items
5.4.7 The allowable deviation for furnace shell assembly shall comply with the requirements in Table 5.4.7.
Quantity to be checked:100%.
Inspection method:See Table 5.4.7.
Table 5.4.7 Allowable deviation for assembly of furnace shell
Note:1 The symbols in the table"D"and"H"refer to design diameter and design height of furnace shell respectively.
2 *refers to verticality of the plane of mouth and hearth to the axis of furnace shell.
5.4.8 The allowable deviation for furnace shell installation shall comply with the requirements in Table 5.4.8.
Quantity to bechecked:100%.
Inspection method:See Table 5.4.8.
Table 5.4.8 Allowable deviation for installation of furnace shell
Note:The backing ring shall be checked at"0"position.
The actually-measured distance from the plane of furnace mouth to the axis of trunnion shall comply with the requirement of the following formula:
Where:L0—distance from the plane of furnace mouth to the axis of trunnion（mm）；
L—design distance from the plane of furnace mouth to the axis of trunnion（mm）；
H0—height of assembled furnace shell（mm）；
H—design height of furnace shell（mm）；
K—allowable deviation，-2.0mm≤K≤1.0mm.