9　Installation of Electric Arc Furnace

9.1　Rail Chair

9.1.1　The rail chair at the electrode side shall be installed in accordance with the following requirements:

1　The longitudinal and horizontal center lines shall be adjusted，and the measurement by plumb wire should be carried out，with the allowable deviation of 2.0mm.

2　The elevation shall be adjusted，and the measurement by optical instrument should be carried out，with the allowable deviation of±1.0mm.

3　The levelness shall be adjusted，and the measurement by leveler should be carried out，with the allowable deviation of 0.20/1000.

9.1.2　The rail chair at the non-electrode side shall be installed in accordance with the following requirements:

1　The levelness shall be adjusted，and the measurement by leveler should be carried out，with the allowable deviation of 0.20/1000.

2　The central distance from the rail chair at the electrode side shall be adjusted，and the measurement by ruler should be carried out，with the allowable deviation of-0.20mm-0.

3　The horizontal center line shall be adjusted，and the measurement by ruler should be carried out，with the allowable deviation of 2.0mm.Its deviation direction shall be consistent with that of the rail chair at the electrode side.

4　The height difference of two rail chairs at the electrode side on the same cross section shall be adjusted，and the measurement by optical instrument should be carried out，with the allowable deviation of 1.0mm.

5　The relative difference of two rail chairs'diagonals shall be adjusted，and the measurement by ruler should be carried out，with the allowable deviation of 3.0mm.The deviation direction shall be consistent with that of the diagonal of the end teeth（or end posts）on curved plate of cradle.