2, according to the stone typesetting determine keel frame;

3. Welding

(1), whether the weld seam is fully welded, because the frame is generally positioned by spot welding first, and several welds will be inadvertently missed during full welding.

(2) Whether the welding slag is cleaned, because if the welding slag is not cleaned after full welding, the antirust paint will be removed.

(3) Whether there is any omission in the application of antirust paint.

4. Check whether the angle steel and channel steel are in conformity with the purchased ones. Because iron is such a thing, cold plating is easy to rust, and hot plating will not rust. It is very important to check whether there are signs of rust in steel when checking rust prevention and welds.