Hot dipped galvanized pipe philippines
The Philippines has a strong demand for hot dipped galvanized pipe. The Philippine national economy is developing rapidly, and the construction industry is developing by leaps and bounds. China is a large manufacturing country of hot dipped galvanized pipe, which can produce high-quality hot dipped galvanized pipe for the Philippines. The Philippine market provides strict specifications and requirements for hot dipped galvanized pipe products. This provides a guarantee for the orderly development of the market.
What is hot dip galvanized steel pipe?
Hot dip galvanizing pipe is the reaction between molten metal and iron matrix to produce alloy layer, so as to combine the matrix and coating. Hot dip galvanizing is to pickle the iron and steel parts first. In order to remove the iron oxide on the surface of the iron and steel parts, after pickling, it is cleaned in ammonium chloride or zinc chloride aqueous solution or ammonium chloride and zinc chloride mixed aqueous solution tank, and then sent to the hot dip galvanizing tank. Hot dip galvanizing has the advantages of uniform coating, strong adhesion and long service life.
How does hot dip galvanized steel pipe work?
Simply put, it is to immerse the cleaned iron parts into the zinc bath through the wetting effect of the plating aid, so that the steel reacts with the molten zinc to form an alloyed film. Good hot-dip galvanizing operation should be that all processes are under strict control and give full play to the function of the process. Moreover, if the operation of the previous process is not good, it will cause chain adverse reactions of the subsequent process, which will greatly increase the operation cost or cause bad hot-dip galvanized products. If the pretreatment is poor, the molten zinc cannot react with steel normally and completely to form the most perfect galvanized film structure. If the post-treatment is poor, the appearance of galvanized film will be damaged and the commodity value will be reduced
Current Chinese national standard for galvanized steel pipe:
1. National standard and size standard of galvanized pipe;
2. GB / t3091-2015 welded steel pipe for low pressure fluid transmission;
3. GB / t13793-2008 straight seam welded steel pipe;
4. GB / t21835-2008 welded steel pipe dimensions and weight per unit length.
What are the uses of galvanized steel pipe?
In the 1960s and 1970s, developed countries in the world began to develop new types of pipes and successively banned galvanized pipes. China's Ministry of construction and other four ministries and commissions have also made it clear that galvanized pipes have been banned as water supply pipes since 2000. Hot dip galvanized steel pipe is widely used in fire fighting, electric power and expressway.
Galvanized pipe is widely used. In addition to being used as pipeline pipe for water transmission, gas, oil and other general low-pressure fluids, it is also used as oil well pipe and oil transmission pipe in petroleum industry, especially in offshore oil fields, oil heater and coal distillation oil washing exchanger of chemical coking equipment, as well as support frame pipe of mine tunnel, etc.
Galvanizing can increase the corrosion resistance of steel pipes and prolong their service life. Zinc is a highly corrosive metal, which can isolate iron from oxygen and water and prevent the chemical reaction required for iron to rust.
What is the difference between hot dip galvanized pipe and galvanized steel pipe?
1、 Different operation methods
Galvanized steel pipe: the zinc in cold galvanized steel pipe is obtained by electroplating at room temperature.
Hot dip galvanized steel pipe: the zinc in hot dip galvanizing is obtained from 450 ℃ to 480 ℃.
2、 Different adhesion
The adhesion of cold galvanized steel pipe is much worse than that of hot-dip galvanized steel pipe. Because the steel pipe matrix and zinc layer of cold galvanized steel pipe exist independently, the zinc layer is very thin, and it is simply attached to the steel pipe matrix, so the cold galvanized steel pipe is easy to fall off.
3、 Different processes
Galvanized steel pipe: the electroplating process is adopted. Only the outer wall of the steel pipe is galvanized, and the inner wall of the steel pipe is not galvanized.
Hot dip galvanized steel pipe: the hot-dip galvanized steel pipe adopts the hot-dip galvanizing process. The inner and outer walls of the steel pipe have zinc layers. The state has made relevant regulations. The cold galvanized steel pipe can not be used as gas pipeline and water pipeline. The corrosion resistance of cold galvanizing is too poor, and the zinc layer is easy to fall off. It has been banned by the state due to potential safety hazards.
Philippine compulsory certification for hot dip metal coating and galvanized color coated steel coil / steel plate
On June 17, 2020, in response to the application submitted by the Philippine enterprises puyat Steel Corporation and sonic Steel Industries Inc. on behalf of the domestic steel industry, the Philippines filed an investigation on the safeguard measures for the import of pre painted galvanized iron - ppgi and pre painted aluminum zinc - ppgl. The products mainly involve galvanized color coated plates and aluminized zinc color coated plates (ASEAN harmonized tariff numbers are 7210.70.11, 7210.70.19, 7210.70.90, 7210.70.91 and 7210.70.99), as well as steel plates coated with other materials (tax numbers are 7210.90.10 and 7210.90.90) and steel strips coated with other materials (tax numbers are 7212.40.11, 7212.40.12, 7212.40.19, 7212.40.91, 7212.40.92 and 7212.40.99).
On December 28, 2020, the Department of industry and trade (DTI) of the Philippines issued dao20-10 administrative decree on compulsory PS certification of hot-dip metal coating and galvanized color coated steel coils and plates for roof and general purposes;
From July 12, 2021, the above products exported to the Philippines must obtain PS and SOC certificates before customs clearance.
From September 12, 2021, DTI of the Ministry of industry and trade of the Philippines will carry out market supervision and impose penalties on dealers / retailers who do not have PS certification for the above products.
Applicable product standards:
PNS 67:2014 Hot-dip metallic-coated steel sheets for roofing – Specification； Specification for hot dip metal coated steel plates for roofs;
PNS 1993:2004 Continuous hot-dip aluminum/zinc-coated steel sheet of commercial, drawing and structural qualities； Hot dip aluminum galvanized steel plates for commercial grade, deep drawing grade and structural grade;
PNS 2003:2004 Continuous hot-dip zinc/5% aluminum alloy coated steel sheets
Hot dip galvanized (Zn-5Al) steel plate;
PNS 1990:2004 hot dip zinc coated carbon steel sheets;
PNS 201:1990 pre painted galvanized steel sheets and coils – specification;
Issued by: Philippine Product Standards Agency BPS;