1, The thickness and quality of the steel plates used in steel buoys should not be lower than the quality requirements of structural steel for hulls specified in GB712.
2, For floating bodies, the metal structure of the steel plate should not be damaged when forming; Before making a float, the steel plate should be free of hammer marks, cracks, porosity, depressions and any defects.
3, The surface of the float after forming should be flat and the flatness should be less than 6mm.
4, All exposed metal edges of the buoy should be transitioned smoothly, and the radius of curvature of its edges should not less than 3mm.
5, The welding of the float should be done by the operator who has obtained the welding qualification certificate; The welding rods used and other welding materials shall comply with the provisions of GB/T5117; The quality of the weld should comply with the provisions of GB/T985.1.
6, If the foam is filled with the float, the float should be processed before filling; The surface of the floating body should be dry and tidy, oil-free, wax-free and paint-free; After filling the foam, no action on the buoy is allowed.
7, The paint used for buoy coating shall comply with the provisions of GB/T 6745 and GB/T 6748.
8, The permissible deviation of the float diameter is ±1% of the float diameter.
9, The watertightness of the floating body should be satisfied to be maintained for 10 minutes at a pressure of 20kPa, and the pressure should not drop.
1, The buoy color is stable, and the pigment should be compatible with the surface material of the buoy; Under the condition of normal use for five years, the surface color of the buoy should comply with the provisions of GB/T8416 and GB4696.
2, The surface material used in the buoy should contain a certain amount of ultraviolet stabilizer, so that it can maintain 50% of the initial fracture strength after 8000h in the xenon anti-aging testing machine.
3, The minimum wall thickness of the buoy float body should comply with the relevant regulations, and the allowable deviation of the wall thickness of the float material is ±1mm.
4, The surface of the buoy should be smooth, no protrusions, no depressions and no blemishes; All exposed edges should be rounded, and the radius of curvature of their edges should be no less than 3mm.
5, The permissible deviation of the float diameter is ±1% of the float diameter.
6, All steel fittings of the buoy should be anti-rust structural steel fittings.
7, Before filling the foam, such as filling the bottom of the floating body with concrete, the concrete should conform to the mix. In the relevant regulations on pouring and maintenance, the total height should not exceed 1/5 of the diameter of the float.
8, If the foam is filled in the float, the float should be processed before filling; The surface of the floating body should be dry, oil-free, wax-free, and paint-free; After filling the foam, no welding on the buoy is allowed.
9, The float should ensure that after being fully immersed in water for 2 hours, its weight is not greater than 1.02 times the floating weight before immersion.
* Test methods
1, Appearance.
viasually check the appearance quality of the buoy.
2, Welding.
Use an ultrasonic flaw detector or other related instrument to inspect the quality of the float weld.
3, Watertightness.
Inflate the buoy float, so that the pressure gauge reading reaches 20kPa, hold it for 10min, check the reading of the pressure gauge, it should remain unchanged.
4, Basic parameter.
1) Diameter of the buoy.
Measure the buoy diameter with a steel tape measure.
2) Buoy draft.
Buoy draft is the distance from the buoy waterline surface to the point where the lowest plane of the buoy is projected on the axis of symmetry. Test the buoy draft with a steel tape measure.
3) Freeboard height.
The freeboard height of the buoy is the shortest distance from the buoy's waterline surface to the upper edge of the float. Measurements can be made with either a steel tape measure or a ruler.
4) Focal height.
Focal height refers to the distance from the buoy watermark to the focal plane of the lamp. Use a steel tape measure to check the focal surface height of the lamp.
5) Float material thickness.
a, Use an ultrasonic thickness gage or other related instrument to measure the thickness of the steel float. For the physical and chemical properties of the steel, the manufacturer's material certificate should be provided.
b, Using a steel tape measure or other relevant thickness measuring instrument, the thickness of non-steel floating materials is detected by drilling at randomly selected locations.
6) Painting.
a, Paint dry film thickness.
Use a coating thickness gage or other related instrument to detect the thickness of the dry film of the paint.
b, painting performance.
According to the test methods specified in GB/T 6745, GB/T 6748 and GB/T8416, the adhesion and other properties of the paint are detected.
5, Operating characteristics.
1), Swing period.
The swing period is the average single swing time of the buoy. More than 10 swing cycles are measured with a stopwatch and their averages are taken.
2), Maximum swing angle.
Refers to the maximum angle between the one-sided inclined buoy axis and the plumb line of the buoy. The maximum swing angle of more than 10 times is determined with a semicircular goniometer and the average is taken.
3), Daily visual distance.
Under the condition of meteorological visibility of 10 nmile (atmospheric transmittance of 0.74), the distance measuring instrument is used to detect the daytime action distance of the buoy by on-site distance pull.
4), Radar detection distance.
Using ship radar equipment, detect the radar detection distance of the buoy.
Ship radar equipment used to determine the radar detection distance has the following characteristics:
a, The height of antenna is 3m.
b, Peak transmit power 3kw.
c, Wavelength 3.2cm.
d, Antenna gain 25dB.
e, Receiver noise value 12dB.
f, 1F bandwidth 10MHz.
g, frequency 9.4GHz
h, Noise factor 16dB.
