Welding characteristics of ms seamless pipe

Posted by zora li on September 21st, 2023

Welding characteristics of ms seamless pipe

The content of carbon and other alloying elements in low carbon steel pipes is low, and its plasticity and toughness are good. During welding, special process measures such as preheating and post-weld heat treatment are generally not required, and complex and special equipment is not required. There is no special requirement for the welding power source, and the general AC and DC arc welding machines can be used for welding. In actual production, due to the good weldability of low carbon steel, almost all welding methods can be selected according to the different processing requirements of the workpiece, and the good quality of the welded joints can be guaranteed.

Advantages of MS pipe
MS pipe is low carbon steel pipe.Low carbon steel pipe is a carbon steel pipe with a carbon content of less than 0.25%. Due to the low carbon content of low carbon steel and good weldability, it is usually not necessary to take special technological measures to obtain high-quality welded joints. Seamless steel pipes, alloy pipes, low and medium pressure boiler pipes, and oil pipes are mostly low carbon steel pipes.

Heat Treatment of Low Carbon Steel Pipes
The annealed structure of low carbon steel pipe is ferrite and a small amount of pearlite, its strength and hardness are low, and its plasticity and toughness are good. Therefore, its cold formability is good, and cold forming can be carried out by methods such as hemming, bending and stamping. However, low carbon steel pipes with very low carbon content have low hardness and poor machinability, and normalizing treatment can improve their machinability.

Low carbon steel pipes have a greater tendency to aging, both quenching and aging tendencies. When the steel is rapidly cooled from a high temperature, the carbon and nitrogen in the ferrite are in a supersaturated state, and it can also slowly form iron carbonitride at room temperature, so the strength and hardness of the steel increase, while the ductility and toughness decrease. This phenomenon is called quench aging.Low carbon steel pipes will age even if they are not quenched and air cooled. After deformation, a large number of dislocations are generated, and the carbon and nitrogen atoms in the ferrite interact elastically with the dislocations, and the carbon and nitrogen atoms gather around the dislocation line. This combination of carbon, nitrogen atoms and dislocation lines is called the old Coriolis air mass (Korpal air mass). It will increase the strength and hardness of the steel while reducing the ductility and toughness, a phenomenon called deformation aging.

Mild steel pipes are sometimes limited in use due to their lower strength. Appropriately increasing the manganese content in carbon steel and adding trace amounts of vanadium, titanium, niobium and other alloying elements can greatly improve the strength of the steel pipe. If the carbon content in the steel is reduced and a small amount of aluminum, a small amount of boron and carbide forming elements are added, the ultra-low carbon bainite group can be obtained with high strength and good plasticity and toughness.

Although low carbon steel pipe is the steel pipe with the best weldability, welding defects such as pores, inclusions and cracks will inevitably occur during the welding process. Therefore, corresponding measures should be taken when welding low carbon steel pipes to ensure the quality of the weld.

Advantages of MS Tubes
1. Low price, easy to smelt
2. Good processing technology
3. Improve performance (C%, heat treatment)

Disadvantages of MS Tubes
1. Poor hardenability
2. Low strength level and low yield ratio
3. Poor tempering stability and poor heat resistance

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zora li
Joined: August 16th, 2022
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