Welding process of rare earth wear-resistant alloy pipe

Rare earth wear-resistant alloy material has advantages that other wear-resistant materials do not have, such as pulverized coal mixer, spiral pipe and other power plant accessories, special-shaped parts can be cast by mold, and pipe fittings series can be formed by centrifugal molding process.

The rare earth wear-resistant alloy tube has high wear resistance, adding FeV, FeNb, Cu, etc., the metallographic structure is lath martensite + bainite, the grain is finer, the strength is higher, and the plasticity is stronger. The high temperature resistance and corrosion resistance of rare earth wear-resistant alloy pipes are also high. The content of Ni and Cr elements in the alloy directly determines the temperature resistance of the material. Rare earth wear-resistant alloy castings have good welding performance, can be cut, and can be butt welded with low-carbon steel. They are suitable for operation, construction, and installation in various places and environments.

The wear-resistant performance of rare earth wear-resistant alloy pipes is good, but the hardness is high, the corresponding mechanical properties such as impact resistance and bending resistance are slightly poor, the weldability is slightly poor, and the hardening tendency is large, so the construction must be strictly in accordance with the process requirements.

Process flow

1. When installing the rare earth wear-resistant alloy pipe, the center line of the pipe and the pipe should be aligned to ensure that the two ends of the pipe are connected accurately.
2. Weld the castings according to the requirements of the drawings, and choose the J507 ordinary electrode as the electrode with a diameter of φ4.0mm.
3. Generally, DC welding machine is used for welding, and AC welding machine can also be used for welding.
4. Select the low current 120~160A for the welding current, and the welding speed should be as slow as possible.
5. Welding should be avoided in rainy days, relative humidity greater than or equal to 90% or low temperature and humid tuyere.
6. The welding parts should be spot welded, symmetrically welded, and then welded as a whole to avoid stress concentration casting cracking.
7. In order to ensure the welding quality of the rare earth wear-resistant alloy pipe, the welding surface should be cleaned to avoid defects such as oil pollution and slag inclusion.
8. For the layered welding parts, after the temperature of the first layer is cooled to 200 ℃ ~ 300 ℃, the welding skin should be cleaned, and then the second layer should be welded, and so on.
9. This process is suitable for butt welding of alloy steel and alloy steel, as well as welding of alloy steel and ordinary steel.