1. wall thickness check
The tool used for wall thickness inspection is mainly a micrometer. When checking, use micrometer to measure the wall thickness of galvanised square pipe one by one. Before checking, first verify whether the certificate of conformity of micrometer is in the validity period, and calibrate whether the micrometer is aligned with the zero position, whether the rotation is flexible, and the measuring surface should be free of scratches and rust spots, and it can be used only after it is qualified. When checking, the left hand holding micrometer bracket, with the right hand to rotate the excitation wheel, the silk rod should be coincident with the diameter of the measurement point, the end measurement should be not less than 6 points, found that the wall thickness is unqualified, should be marked.
2. Outside diameter and ellipticity check
Outside diameter and ellipticity check the tools used are mainly calipers, vernier calipers. When checking, measuring the outer diameter of galvanised square tubes one by one with qualified calipers. Before the inspection, first verify whether the certificate of conformity of the card gauge in the validity period, and vernier calipers calibrate the card gauge used, the measurement surface whether there are scratches and rust spots, qualified before use. When checking, the card gauge should be perpendicular to the axis of the galvanised square tube, galvanised square tube slowly rotating, measuring the cross-section where the outer diameter found to be large or small, should be marked.
3. Length check
Galvanised square tube length checking tool used is mainly a steel tape, measuring length, tape "O" point aligned with one end of the galvanised square tube, and then tighten the tape, so that one side of the tape scale is close to the surface of the galvanised square tube, galvanised square tube at the other end of the tape length is the length of the galvanised square tube.
4. Curvature check of galvanised square tube
Bend check of galvanised square pipe is mainly to check the total length of galvanised square pipe bend, bend per metre, the tools used are mainly level ruler, plug ruler and fishing line. Measure the total bending degree of galvanised square pipe, use the fish line to align with one end of galvanised square pipe, and then pull the fish line tightly, so that one side of the fish line is close to the surface of the galvanised square pipe, and then use the ruler to measure the distance between the surface of the galvanised square pipe and the gap of the fish line, that is, the total length of the galvanised square pipe bending degree.
