Can stainless steel pipe and carbon steel pipe be welded?

Can stainless steel and carbon steel be welded?

To be sure, it can be welded, which belongs to the welding of dissimilar steels.

The welding rods used must be welding rods or wires for welding this type of stainless steel. Generally, it is not recommended to weld stainless steel pipes and carbon steel pipes together. It is more suitable to use flange connections, because long-term contact between stainless steel and carbon steel will produce " Carburizing reaction" will have an impact on the characteristics of stainless steel.

The weldability of dissimilar materials mainly depends on the metallurgical compatibility, physical properties, surface state, etc. of the two materials. The greater the difference in these properties between two or more materials to be welded, the poorer the weldability. In addition, the weldability of dissimilar materials is also related to the welding process, including factors such as the size of the welded joint, the form of the groove, the orientation of the weld, the parameters of the welding process, and the operating level of the welding process.

When welding these two steels, electrode arc welding, submerged arc welding, CO2 gas shielded welding and mixed gas shielded welding can be used. When using mixed gas shielded welding, the volume fraction (%) of the mixed gas has the following types:

Ar/98+CO2/2; Ar/40+C02/60; He/40+C02/60; He/20+C02/80; Ar/75+C02/3+02/2. These ratios can effectively prevent weld pollution and obtain the best weld appearance.

In order to prevent the formation of cold cracks and cells in the dissimilar steel welded joints of these two grades, preheating must be performed before welding; in order to improve the mechanical properties of the dissimilar steel welded joints, tempering heat treatment should be carried out after welding.

Extended information:

Chromium stainless steel has certain corrosion resistance (oxidizing acids, organic acids, cavitation), heat resistance and wear resistance. Usually used in power plants, chemicals, petroleum and other equipment materials. Chromium stainless steel has poor weldability, attention should be paid to welding process, heat treatment conditions and selection of suitable welding electrodes.

Chromium 13 stainless steel has high hardenability after welding and is prone to cracks. If the same type of chromium stainless steel electrode (G202, G207) is used for welding, preheating above 300°C and slow cooling at about 700°C after welding must be carried out. If the weldments cannot be heat treated after welding, chrome-nickel stainless steel electrodes should be used.

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