Pipe fitting with zinc plated at outer part and plastic coated at inner part as well as production process of same

Abstract

The invention relates to a pipe fitting with zinc plated at the outer part and plastic coated at the inner part as well as a production process of the same. In order to overcome defects in the prior art, the invention provides the pipe fitting with the zinc plated at the outer part and the plastic coated at the inner part as well as the production process of the same. The technical scheme is that: the pipe fitting with the zinc plated at the outer part and the plastic coated at the inner part comprises a galvanized layer (1) and malleable steel piece base body (2), and also comprises a polyethylene or epoxy / polyester coating layer (3). The production process of the pipe fitting with the zinc plated at the outer part and the plastic coated at the inner part comprises the following steps of: blasting sand on an inner wall of a galvanized pipe fitting, deoiling the galvanized pipe fitting in a neutral environment, cleaning the galvanized pipe fitting by using hot water once, cleaning the galvanized pipe fitting by using hot water for the second time, preheating the galvanized pipe fitting, providing the galvanized pipe fitting with a facing, powdering the galvanized pipe fitting, removing the facing of the galvanized pipe fitting, curing, leveling and inspecting the galvanized pipe fitting, removing rust in screw threads of the galvanized pipe fitting, packaging the galvanized pipe fitting, and putting the galvanized pipe fitting in storage. The plastic coating process provided by the invention has the advantages of simplicity in operation, high production efficiency, high adhesion force, no easiness for the separation of layers and stability in product quality as the inner wall of the galvanized pipe is subjected to phosphating and sand blasting treatment.

Description

technical field [0001] The invention relates to the steel-plastic composite pipe technology, in particular to an outer galvanized inner plastic-coated pipe fitting and a production process thereof. Background technique [0002] With the rapid development of our country's economy and the continuous improvement of people's lives, the pipe processing industry has also developed rapidly, making great contributions to the national and local economies. Internal and external galvanized pipe fittings occupy a considerable proportion in the domestic market, and issues such as sanitation, environmental protection, energy saving and emission reduction have become increasingly prominent. After the Hong Kong Taxation Office issued a notice in 1995 to prohibit the use of enamelled galvanized steel pipes for drinking water supply equipment in houses, in 1998 the Shanghai Municipal Construction Committee also issued a notice prohibiting the use of food-belly steel doors and windows and galv...

AI Technical Summary

Problems solved by technology

In the patent CN2379688: "External galvanized internal plastic-coated tap water pipe fittings", no specific manufacturing process is mentioned. At present, whether it is external galvanized internal plastic-coated pipes or pipe fittings, there are generally poor adhesion and easy peeling of the coating. and many other defects

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