Views: 2 Author: Site Editor Publish Time: 2025-08-21 Origin: Site
As a commonly used material that combines anti-corrosion performance and structural strength, the fulfillment of orders for hot dip galvanized steel pipe is a comprehensive reflection of technical details and service guarantees.
At the beginning of this year, a regular customer from Kazakhstan received a project for the renovation of high-pressure pipelines. Due to previous pleasant cooperation, the customer gave priority to Shanghai Zhucheng, a supplier from China. So they sent us a procurement request for hot dip galvanized steel pipe. In the initial communication, the client clearly stated two core requirements: first, all steel pipe ends need to be threaded, and second, the packaging needs to achieve the effect of protecting the threaded ports and hot-dip galvanized layer.
The port needs to be threaded, and this hot-dip galvanized steel pipe is obviously to be used in high-pressure medium conveying systems, which requires connection with forged high-pressure threaded pipe fittings. This requires the thread of the steel pipe end to be consistent with the standard of the threaded pipe fittings connected. In response to this requirement, we have confirmed with the customer that the form of the port thread needs to be NPT thread.
In terms of packaging, the customer emphasized the need for protection during transportation. Due to the long distance of exporting these steel pipes from China to Kazakhstan by land, the customer is very concerned about safety issues during transportation. We have designed a comprehensive protective packaging solution to meet the needs of our customers. For threaded ports, we have added plastic pipe caps to protect them from damage during transportation; The inner layer is wrapped with bubble wrap that can buffer impact and also prevent the zinc layer from being affected by moisture and oxidation during transportation; The outer layer is wrapped with thick rainproof cloth and tied with steel straps. The weight of each bundle of steel pipes is controlled within 2 tons, and it is easy to load and unload with lifting straps. Before shipment, we will send the packaged pictures to the customer for confirmation, ultimately allowing them to confirm the shipment with peace of mind.
During the arrival inspection, the customer highly praised the thread accuracy and packaging integrity, with a 100% pass rate for thread inspection and no damage to the zinc layer surface, laying a solid foundation for subsequent pipeline installation projects.
DESCRIPTION | Connection Type | Size | QTY | Unit | Rrmark |
PIPE, A53 Gr. B, CS-HDG, SEAMLESS, NPT ENDS, AS PER ASME B36.10M, SCH80 | MNPT | 3" (80) | 672 | m | hot-dip galvanizing |
2" (50) | 192 | m | hot-dip galvanizing | ||
1-1/2" | 18 | m | hot-dip galvanizing | ||
1" (25) | 432 | m | hot-dip galvanizing | ||
3/4" (20) | 18 | m | hot-dip galvanizing | ||
1/2" (15) | 546 | m | hot-dip galvanizing | ||
TOTAL | 1878 | ||||
Hot dip galvanized steel pipe, requires carbon steel pipe to undergo sandblasting and rust removal treatment, and then immersed in molten zinc solution (about 460 ° C) to attach a dense and thick layer of zinc on its surface. The purpose is to prevent carbon steel from rusting and corroding during use and extend its service life. The process mainly includes three stages: pre-treatment, hot-dip galvanizing, and post-treatment.
Degreasing: Removing grease and dirt from the surface of steel pipes.
Acid washing: Soak in acid solution (usually hydrochloric acid or sulfuric acid) to thoroughly remove surface rust and oxide scale.
Assisted plating: Immerse in ammonium zinc chloride assisted plating solution to prevent the steel pipe from oxidizing again before entering the zinc pot and increase the adhesion of the zinc layer.
Immerse the pre treated steel pipe into molten zinc solution maintained at a temperature of 445 ° C-465 ° C.
Steel pipes undergo complex physical and chemical reactions with zinc liquid, forming iron zinc alloy layers and pure zinc layers.
Cooling: After being removed from the zinc pot, immediately perform water cooling or natural cooling to solidify the zinc layer, with a coating thickness usually above 85 μ m.
Passivation: Sometimes chromate passivation treatment is performed to form a protective film that prevents the formation of "white rust" (zinc oxide) during transportation and storage.
Inspection and shaping: Check the thickness, uniformity, and surface quality of the coating, and perform necessary straightening.
Firstly, it has excellent anti-corrosion performance, which can achieve a service life of 30-50 years in natural environments, far exceeding that of ordinary carbon steel pipes;
Secondly, it has comprehensive protective capabilities, with a zinc layer covering both the inner and outer surfaces of the steel pipe and all corners, eliminating any dead corners for corrosion prevention;
The third is higher cost-effectiveness. Although the initial procurement cost is higher than that of ordinary steel pipes, there is no need for frequent maintenance and replacement during long-term use, resulting in lower overall costs.
During the hot-dip galvanizing process, industrial waste such as zinc slag is generated, and improper treatment can easily cause environmental pollution;
High temperature galvanizing will cause certain thermal deformation in steel pipes, which is not suitable for mechanical processing scenarios with extremely high precision requirements;
In addition, the zinc layer has low hardness and is prone to scratches under severe collisions or friction, which affects the anti-corrosion effect.
Hot dip galvanized steel pipes are often used in pipeline systems exposed to the external environment due to their strong corrosion resistance.
Building structure: scaffolding in construction (now gradually replaced by buckle scaffolding), main load-bearing structure of steel structure factory buildings, roof trusses, etc.
Fluid transportation: used as water pipes, gas pipes, heating pipes, oil pipes, etc. In the past, it was widely used for domestic water supply, but due to long-term use, rust may form on the inner wall, affecting water quality. It has gradually been replaced by plastic pipes (PPR), stainless steel pipes, etc., but it is still widely used in fire sprinkler systems.
Municipal engineering: road guardrails, streetlight poles, traffic sign poles, transmission towers, radio and television towers, etc.
Agriculture: skeleton of greenhouse and irrigation system pipes.
Mechanical equipment: mechanical structural components, material conveying pipelines, etc. that require rust prevention protection.
During the construction process, safety issues cannot be ignored.
Special lifting tools must be used during transportation to avoid direct binding of steel wire ropes and scratching of the zinc layer;
When installing threaded connections, the debris on the surface of the threads should be cleaned first, and special sealant or tape should be applied to ensure a tight and leak free connection;
Wear dust masks and goggles when cutting steel pipes to prevent zinc dust inhalation and debris splashing;
Good ventilation must be maintained during welding operations, as the zinc oxide smoke generated by the evaporation of the zinc layer at high temperatures can cause damage to the human respiratory system;
After installation, the damaged zinc layer should be repaired in a timely manner using zinc rich coating to maintain the overall anti-corrosion performance.
Hot dip galvanized steel pipe is an economical, practical, and durable solution for steel corrosion prevention. They still play an irreplaceable role in structural and non potable fluid transportation fields that require long-term exposure to the atmosphere or mild corrosion environments.
