Welding Properties of Low Alloy Duplex Stainless Steel 1Cr21Ni5Ti

Introduction

Low alloy dual phase stainless steel (1Cr21Ni5Ti) has been developed for its excellent mechanical properties in view of its resistance to strong corrosion and oxidation at high temperatures.The main feature of the alloy is that it is composed of ferrite and austenite dual-phase structure. The strength of the material is improved when the solid stability is decreased, thus the selection of substrates and welding technologies must be taken into account for the welding procedure to obtain a good weld joint.

Heat Affected Zone(HAZ)

When dual phase stainless steel 1Cr21Ni5Ti is welded, the steel forms a heat affected zone (HAZ) around the weld spot, which compromises the microstructure of the weld. This can cause the tensile strength of the welded joint to decrease, as grain boundaries are disrupted or eliminated in the HAZ. Also, phases such as martensite or bainite may form within the HAZ, which can lead to premature failure of the joint or corrosion in the welded area. The HAZ in dual phase stainless steel is also affected by the weld parameters, such as the welding current, arc length, and travel speed. In addition, the welded area of dual phase stainless steel is more susceptible to hot cracking when the welding speed is too fast.

Welding procedure

When welding dual phase stainless steel 1Cr21Ni5Ti, the welding parameters and filler metal selection should be considered in order to get the best possible weld joint. When choosing the welding current, it should be in the range suggested by the manufacturer, it should also take into account the particular requirements for the weldment and be adjusted accordingly. The filler metal should be selected according to the EN standard, as the joint strength and corrosion resistance should be taken into account. The arc length should be around 3-5 mm, while travel speed should not be too fast. As for the post-weld heat treatment, it should be avoided, as it reduces the strength of the weld joint.

Conclusion

Dual phase stainless steel 1Cr21Ni5Ti has excellent mechanical properties and corrosion resistance, which makes it an ideal material for many applications. However, it is important to take into account the welding parameters and filler metals when welding this material in order to get a good weld joint and to ensure the best possible performance of the joint.

Weldability of Low Alloy Duplex Stainless Steel 1Cr21Ni5Ti

Low alloy duplex stainless steel 1Cr21Ni5Ti provides strength, high resistance to pitting, excellent thermal conductivity and localized forging and welding. It is used for construction of components and equipment exposed to corrosive media, for instance the chemical industry and paper industry.

Welding of the low alloy 1Cr21Ni5Ti stainless steel requires careful selection of welding parameters and techniques, depending upon the welding position and the welding procedure to be used. A major criterion is the correct selection of the correct welding current, that is, the necessary amount of current, voltage and number of welding cycles should correspond to the reflection coefficient of the joint. As the arc is quenched, it generates generated a more intense heat, which is then transferred through the oxide layer, accelerating the diffusion of alloying elements. As a result, the weld is more resistant to corrosion.

When welding the low alloy 1Cr21Ni5Ti stainless steel, attention should be paid to the electrical conductivity of the steel, especially when the welding current must last for some time and arc stability. It is also important to learn about the influence of nickel content on the microstructure and corrosion resistance of welded structure, as nickel content may typically range from 6 to 25%. Generally, higher nickel content will result in higher weldability and when reducing the nickel content, appropriate welding processes and parameters should be selected.

To protect the welded area from any kind of corrosion, the use of appropriate flux and gas should be considered. Proper flux is important for improving the wetting ability of the weld and to avoid oxidation of the weld. In addition, the proper use of filler material is important as it should match the parent material and oxidation should be avoided.

In conclusion, it should be noted that the welding process of low alloy 1Cr21Ni5Ti stainless steel demands thorough knowledge of the properties of the material, correct welding parameters and specific welding techniques. Both material selection and welding operation control are very important for achieving the best welding results. The right combination of these parameters can guarantee the weld performance, enhance finishing and avoid oxidizing during weld.