5.6 Fabrication of Shell
Ⅰ Dominant Items
5.6.1 The steel plate shall not have lamination and inclusion at edge after the shell is bent and formed，the actual thickness of steel plate after base treatment shall not be less than the allowable minimum thickness.
Check quantity:full check.
Check method:lamination and inclusion by visual check.
Thickness of steel plate is inspected by caliper or ultrasonic.
5.6.2 The steel shall have no crack，slag inclusion，lamination and missing edge larger than 1.0mm on the cutting or shearing face.
Check quantity:full check.
Check method:observe or check with a magnifier.
5.6.3 The pressure test of shell shall meet the requirements in the design documents.It shall meet the requirements in Appendix E of this standard when not specified.
Check quantity:full check.
Check method:check the pressure test report.
Ⅱ General Items
5.6.4 The welding lug，scaffold lug，fixing piece and positioner for fixtures on each shell steel plate shall meet the requirements in the technical attachment of the contract.
Check quantity:20% random check for shell steel plate assemblies，and at least 10 pieces.
Check method:visual check.
5.6.5 The bending processing of shell steel plate shall meet the requirements of curvature radius specified in the design document，an arched template with chord length no less than 1500mm shall be used for check and the clearance shall not be larger than 2.0mm.
Check quantity:30% random check for elements.
Check method:check the processing quality records or measure.
5.6.6 The hot-blast stove shell，hot-blast stove bottom and connected first ring shell，top arch shell on hot-blast stove and shell at high temperature section shall be pre-assembled and the pre-assembling records shall be taken.
Check quantity:full check.
Check method:check the pre-assembling records and take visual check.
5.6.7 The surface of element shall be clean without concavity or damage，the joint shall be smooth，the scar shall be repaired and ground after the temporary fixtures are removed.
Check quantity:10% random check for elements and at least 5 pieces.
Check method:visual check.
5.6.8 The cross centerline and splicing line shall be marked on the shell element.The alignment mark shall be obviously painted and stamped at disconnected joint or between upper and lower ring.
Check quantity:10% random check for elements and at least 5 pieces.
Check method:visual check.
5.6.9 The reinforcing measures against permanent deformation shall be taken for elements，e.g.shell.
Check quantity:10% random check for elements and at least 5 pieces.
Check method:visual check.
5.6.10 The tap hole，slag hole，tuyere，flange hole on cooling plate，water hole on cooling wall shall be drilled after the fabrication and pre-assembling of furnace shell and reference lines shall be marked for these holes according to the design documents，the drilling deviation shall also meet the requirements in the design documents.
Check quantity:full check.
Check method:observe and check with steel rule.
5.6.11 The connecting flange between blast furnace shell and equipment，e.g.tap hole nozzle，tuyere flange，cooling plate flange，etc，shall meet relevant requirements in Chapter 6 of this standard during assembling and welding in the manufactory.
Check quantity:full check.
Check method:visual check.
5.6.12 The allowable pre-assembling deviation for steel plates on shell of blast furnace，hot-blast stove，etc shall meet the requirements in Table 5.6.12.
Check quantity:full check.
Check method:see Table 5.6.12.
Table 5.6.12 Allowable pre-assembling deviation for steel plate on shell of blast furnace，hot-blast stove（mm）
Table 5.6.12（Continued）
Notes:1h refers to the height of pre-assembled shell；d refers to the design diameter of shell；t refers to the plate thickness.
2 The alignment deviation and clearance at joint end shall meet the requirements in procedure for automatic welding when it is
employed.
5.6.13 The bottom plate of blast furnace shall be pre-assembled during fabrication and its allowable deviation shall meet the requirements in Table 5.6.13.
Check quantity:full check.
Check method:see Table 5.6.13.
Table 5.6.13 Allowable pre-assembling deviation of bottom plate（mm）
Note:L refers to width of circular plate；D refers to diameter of furnace bottom plate.
5.6.14 The water-cooled beam at bottom of furnace shall be pre-assembled during fabrication and its allowable deviation shall meet the requirements in Table 5.6.14.
Check quantity:full check.
Check method:see Table 5.6.14.
Table 5.6.14 Allowable pre-assembling deviation of bottom water-cooled beam（mm）
Note:D refers to the diameter of the circle that is constructed by the supporting beam.