MS and GI Pipe Difference

Galvanized iron pipes commonly used on water pipe lines, it is dipped into zinc for corrosion protection

GI Pipe is “Galvanized Iron” Pipe. Material ms is mild steel and gi is galvanized steel that has been hot dipped .These days the pipe will likely be made from steel rather than iron. Galvanized iron pipes commonly used on water pipe lines.

Mild steel is untreated and usually hot or cold rolled or in the case of pipe extruded while molten. Low carbon content and rusts in humid weather and can be bent easier than other steel. Its not black pipe used for gas, its not case hardened with cyanide, its not galvanized with zinc plating, its not blued like used for guns, its not cast like for cast iron furniture. Its the most affordable type of steel.

Mild steel pipe refers to the content of less than 0.25% carbon steel because of its low strength, low hardness and soft. It includes most of the part of ordinary carbon steel and high-quality carbon structural steel, mostly without heat treatment used in engineering structures, some carburizing heat treatment and other mechanical parts required for wear.

Difference between galvanized iron pipe (GI) and mild steel pipe (MS):

Although galvanized steel pipes and mild steel pipes (carbon steel pipes) both belong to the category of steel pipes, their materials and uses are quite different.

1. Material properties
Galvanized steel pipes are mainly covered with a layer of zinc on the surface of the steel pipes through hot-dip galvanizing to improve its corrosion resistance and durability. ‌‌However,‌because the galvanized layer is not uniform,‌it is prone to corrosion when exposed to the external environment.

Mild steel pipes (low carbon steel) are made of sophisticated carbon structural steel or low alloy structural steel. Due to their high strength and wear resistance, they are widely used in the manufacturing of machine parts and structural parts. It also has high corrosion resistance and high temperature strength and is widely used in chemical, oil and gas industries. ‌ Its material properties make it highly malleable and strong, ‌ suitable for applications requiring high strength and weight.

2. Manufacturing process
The manufacture of galvanized steel pipe involves coating the pipe with a layer of zinc through a process such as hot-dip plating or electroplating, which can improve the pipe's corrosion resistance and durability but can also distort the pipe's size and shape. ‌

The manufacturing of mild steel pipes includes perforating steel ingots or solid round steel to form capillary tubes, which are then hot-cold rolled and cold-drawn. ‌This process occupies a key position in the domestic steel pipe field.

3. Cost
The production process of galvanized steel pipe is more complicated and requires galvanizing treatment, so the cost is higher. ‌
The production process of mild steel pipes is relatively simple and the cost is low.

4. Application scope
Galvanized steel pipes are mainly used in water supply, fire protection, aviation and other fields because of their good corrosion resistance. ‌
Mild steel pipes are widely used in petroleum, chemical, natural gas and construction industries due to their high strength and excellent quality characteristics.

To sum up, ‌galvanized steel pipes and mild steel pipes each have their own advantages, and ‌choosing which steel pipe is better depends on the specific usage scenarios and needs. ‌

Expand information:

Classification of galvanized steel pipes:
Galvanized steel pipes are divided into cold-dip galvanized steel pipes and hot-dip galvanized steel pipes. Cold-dip galvanized steel pipes have been banned, and the latter has been advocated by the country for temporary use.

Hot-dip galvanized pipe:
Hot-dip galvanizing pipe reacts molten metal with an iron matrix to produce an alloy layer, thereby combining the matrix and the coating. Hot-dip galvanizing is to pickle the steel pipe first. In order to remove the iron oxide on the surface of the steel pipe, after pickling, it is cleaned in an aqueous solution of ammonium chloride or zinc chloride or a mixed aqueous solution of ammonium chloride and zinc chloride, and then sent to in a hot dip plating tank. Hot-dip galvanizing has the advantages of uniform coating, strong adhesion, and long service life. The hot-dip galvanized steel pipe matrix undergoes complex physical and chemical reactions with the molten plating bath to form a corrosion-resistant zinc-iron alloy layer with a tight structure. The alloy layer is integrated with the pure zinc layer and the steel pipe matrix, so it has strong corrosion resistance.

Cold-dip galvanized pipe:
Cold-dip galvanized pipe is electro-galvanized. The amount of galvanizing is very small, only 10-50g/m2. Its corrosion resistance is much worse than that of hot-dip galvanized pipe. Regular galvanized pipe manufacturers, in order to ensure quality, most do not use electro-galvanizing (cold plating). Only small businesses with small scale and old equipment use electro-galvanizing, and of course their prices are relatively cheaper. The Ministry of Construction has officially announced that cold-galvanized pipes with backward technology will be phased out and cold-galvanized pipes are not allowed to be used as water and gas pipes. The zinc layer of cold-dip galvanized steel pipe is an electroplated layer, and the zinc layer is layered independently from the steel pipe matrix. The zinc layer is thin, and the zinc layer simply adheres to the steel pipe matrix and falls off easily. Therefore, its corrosion resistance is poor. In new residential buildings, it is prohibited to use cold-dip galvanized steel pipes as water supply pipes.

Applications of galvanized steel pipes:
Galvanized steel pipe is a welded steel pipe with a hot-dip or electroplated zinc layer on the surface. Galvanizing can increase the corrosion resistance of steel pipes and extend their service life. Galvanized pipes are widely used. In addition to being used as pipeline pipes for general low-pressure fluids such as water, gas, and oil, they are also used as oil well pipes and oil pipelines in the petroleum industry, especially offshore oil fields, and as oil heaters and condensators in chemical coking equipment. Pipes for coolers, coal distillate wash oil exchangers, pipes for trestle pipe piles, and support frames for mine tunnels, etc.

Hot-dip galvanized steel pipes are widely used in construction, machinery, coal mines, chemical industry, electric power, railway vehicles, automobile industry, highways, bridges, containers, sports facilities, agricultural machinery, petroleum machinery, prospecting machinery, greenhouse construction and other manufacturing industries.

Read more: Carbon steel vs Stainless steel