1. Surfacing Stellite alloy

According to AWS A5.13-2000 "Specification for Hardfacing Electrodes for Protective Metal Arc Welding", the most commonly used cobalt-based wires are:

①RCoCr-A(STL6)

②RcoCr-B(STL12)

③RcoCr-C(STL1)

The three kinds of welding wires are casting low-carbon, medium-carbon, high-carbon cobalt-chromium-tungsten alloy surfacing welding wires, and the surfacing layer has good corrosion resistance, heat resistance and wear resistance.

These properties are maintained at temperatures up to 800°C.

STL6 has the lowest carbon and tungsten content, and is the most ductile welding wire. Therefore, it can withstand the impact under hot and cold conditions, and there is less possibility of cracking.

STL12 has a medium carbon and tungsten content, has medium hardness, and has better wear resistance than STL 6, but slightly less plastic. Both of them can be cut with cemented carbide tools, and the metallographic structure of the two is a solid solution (austenite) containing tungsten, chromium and cobalt and chromium-tungsten complex carbide eucrystal.

STL1 is the one with the highest carbon content and tungsten content, so the hardness is also the highest, and the wear resistance is very good; However, the impact resistance is poor, and the plasticity is the worst. It is difficult to weld, to weld quickly with a small current, the weldment should be heated to more than 250 °C as a whole before welding, keep the constant temperature welding, and carry out heat treatment immediately after completion. Prevents the weld bead from deforming and forming stress cracks.

2. Surfacing UTP 65 electrode

According to the analysis of domestic surfacing welding experience, the electrode containing C≥2.5% is prone to cracking tendency on any material, and reasonable technological measures must be taken during welding to avoid welding cracks.

UTP65 surfacing welding electrode contains C4.5%, HRC≥60, this type of electrode is more prone to macroscopic cracks, and reasonable process measures can also avoid or reduce cracks, which is subject to the previous process evaluation.