4.3 Rotary Hearth Equipment
4.3.1 The upper and lower hearth of the furnace shall be preassembled respectively before delivery.The allowable manufacturing deviations of both upper and lower chassis shall comply with the following requirements:
1 Tolerance of flatness of the top surface of upper chassis shall be 10mm，and allowable joint mismatch of sector steel structure shall be 2mm.
Check method:Checking with special tools.
Sample size:100%.
2 The allowable deviations of radius of inner and outer arc angle plates（firebricks）shall comply with the requirements in Table 4.3.1-1.
Table 4.3.1-1 Allowable deviations of radius of inner and outer arc angle plates（firebricks）
Check method:Checking with special tools.
Sample size:100%.
3 Tolerance of planeness of bottom plane of lower chassis shall not be larger than 4mm.
Check method:Checking with special tools.
Sample size:100%.
4 Allowable tolerance of planeness of the bottom plane of support rail board shall be 2mm；the joint of support rail board shall be spliced at a 45° angle，moreover，the height difference at the rail joint shall not be larger than 1mm；joint gap shall be 5 to 10 mm，the uneven part of joint shall be levelled by grinding wheel，the leveled length of rail end shall not be larger than 100mm，moreover，smooth transition shall be realized，the bottom surface of rail board shall contact the bottom plane of lower chassis，and backing plates should be used if such contact isn't flat，moreover，the gap between backing plates shall be smaller than 500mm.The allowable deviation of radius of support rail board shall be±4mm when the average diameter of rotary hearth furnace is smaller than 20.0m，and±7.5mm when such average diameter is larger than 20.0m.
Check method:Checking with special tools.
Sample size:100%.
5 The joint of centering rail board shall be spliced at a 45° angle，and the allowable radial deviation of joint shall not be larger than 1mm，moreover，the joint gap shall be 6 to 10 mm；the untidy joint may be levelled，moreover，smooth transition shall be realized；The allowable deviations of radius of the centering rail plane and allowable tolerance of verticality of the plane with respect to the support rail plane shall comply with the requirements in Table 4.3.1-2.
Table 4.3.1-2 Allowable deviations of radius of centering rail plane and allowable tolerance of verticality of plane with respect to support rail plane
Check method:Checking with special tools.
Sample size:100%.
6 The allowable deviation of center distance between the neighboring pinteeth holes in pin tooth ring shall be±0.2mm，the cumulative allowable deviation of center distance shall be±0.6mm.The allowable height difference between the horizontal plane formed by midpoints of pin shafts of pin gear and the plane formed by midpoints of drive wheel shall be±2mm.The allowable radius deviations of the circle formed by pin hole center shall comply with the requirements in Table 4.3.1-3.
Table 4.3.1-3 Allowable tolerances of radius of circles formed by pin hole centers
Check method:Checking with special tools.
Sample size:100%.
4.3.2 The allowable deviations of the field installation of the rotary hearth equipment shall comply with the requirements in Table 4.3.2.
Table 4.3.2 Allowable deviations of installation of rotary hearth equipment
4.3.3 Commissioning of the rotary hearth equipment shall comply with the requirements in current national standard GB 50386 Code for Acceptance of Engineering Installation for Mechanical Equipment of Rolling Mill.
Check method:Field test run and making records.
Sample size:100%.