Carbon steel pipe fittings

Carbon steel pipe fittings groove fittings surface should be flat, clean, there should not affect the performance of porosity, sand eyes, slag, cold compartment, shrinkage, cracks and depressions and other defects. Cast groove parts should be free from defects such as bulges and depressions. Grooved fittings should be free from processing defects and knock-on damage. Markings should be clear and rowable.

Carbon steel pipe fittings can be coated with electrophoretic paint, plastic or hot dip galvanising for surface and corrosion treatment, where the electrophoretic paint coating method of trench fittings should not be used for domestic drinking water supply. The dimensions of the trench interface after surface treatment shall conform to the provisions of Appendix C of GB/T36019-2018, and the corrosion protection layer shall conform to the following provisions respectively:

 ) paint layer: uniform, smooth, firm, no paint tumor, accumulation of paint, leakage of paint, paint layer thickness of not less than 25.4 &undefined;, paint layer containing less than 0.009% of lead.

b) The plastic layer is uniform, continuous, smooth and firm. Epoxy coating thickness of plastic coated trench fittings should be not less than 130, by mutual agreement between supply and demand, can be specified epoxy coating thickness greater than 130 other thickness of polyethylene coating thickness should be in line with the same nominal size steel-plastic pipe plastic layer thickness requirements in Table 2. The plastic layer should be covered intact at the installation with parts such as the groove of the pipe fittings, and the thickness should be not less than 40 and not affect the installation.

c) hot dip galvanized layer: zinc layer uniform, continuous, smooth, no leakage, zinc layer off, black spots and other defects and rubber ring / pad contact surface should not be zinc tumor, zinc slag, pile of zinc and other appendages zinc layer of lead content of not more than 0.1% zinc layer thickness of not less than 65 .

Carbon steel pipe fittings bolts, nuts should be hot-dip galvanized surface corrosion treatment, and comply with the provisions of GB/T5267.3. Galvanized layer thickness should be not less than 40 galvanized layer surface should be smooth, no leakage, zinc tumor, black spots, no residual solvent slag, oxide inclusions and other defects that damage the intended use of parts performance. Preference shall be given to hot-dipped galvanized bolts and nuts. By mutual agreement between supply and demand, other materials and coated bolts and nuts can be supplied.