Cobalt-based hard alloy surfacing on the surface of the pipe of the pigging valve
1 Overview
The surface of the conventional pigging valve sphere is generally hardened by Ni-P electroless plating in order to improve corrosion resistance and scratch resistance. However, in some special working conditions, such as media containing a large amount of solid hard particles, the surface of the sphere is washed and worn, which is easy to cause valve leakage, and other hardening methods other than Ni-P electroless plating must be selected.
At present, commonly used sealing surface hardening methods include supersonic flame spraying, nickel-based alloy thermal spraying, laser cladding, hard chrome plating and hardfacing of hard alloy. For the high-pressure hard-sealed pigging valve trialed by our company, according to the existing equipment conditions, it is decided to choose the manual tungsten-arc welding process to obtain a thick surfacing layer on the surface of the ball to achieve corrosion resistance and erosion resistance. purpose.
2. Welding materials
In this test, HS111 (ER CoCr-A) and HS112 (ER CoCr-B) cobalt-based hard alloy surfacing welding wire of f 4.0mm were selected, and the alloy composition is shown in Table 1 and Table 2. The hardness of the surfacing layer of HS111 is 40-45HRC, and the hardness of the surfacing layer of HS112 is 45-50HRC.
3. Surfacing test
The 8′′ pigging valve sphere (see Figure 1) is used for the surfacing process test. The ball material is WCB, in the normalized state, the surface of the ball is pre-welded according to the “2.5 mm alloy thickness after processing to the finished productâ€. After the rough processing of the part, the coloring test is performed, and casting defects such as pores, blisters, and cracks are eliminated by grinding and repair welding.
For more details, please refer to the attached content or the contents of Metalworking (Hot Processing) magazine.
Light-Duty Patent Series,Pu Caster,Light-Duty Wheel,Furniture Swivel Caster
BENYU CASTERS & WHEELS CO.,LTD , https://www.benyucaster.com