How to fix the regulating pneumatic valve surfacing method

high pressure regulating pneumatic valve open failure, seriously affecting the safe and stable operation of unit. Collapse of inspections of pneumatic valve, found that high pressure regulating valve pneumatic seat sinking mm, lead to pneumatic valve disc guide convex shoulder out of the groove, unable to steam which can adjust the normal. Given the temporary repair time is short, pneumatic seat sinking site difficult to restore, decided to adopt welding processing, increase the height of the guide convex shoulder, restores the high voltage main steam adjusting the use function of original pneumatic valve.

high voltage main steam adjusting pneumatic valve repair methods
and working mechanism of pneumatic valve disc guide convex shoulder unit built for dongfang ( N - 。 / / - - - - - - Type steam turbine, its high voltage main steam adjusting pneumatic valve is made up of a main steam of pneumatic valve and a regulating pneumatic valve, pressure regulating pneumatic valve is used to adjust the volume of the admission of high pressure cylinder. Oil unit operation, motivation as a mechanical lifting device, pneumatic valve disc guide convex shoulder move up and down along the guide groove, control the opening of pneumatic valve disc. Unit operation, adjustment of pneumatic valve for high temperature steam. MPa, ℃, guide convex shoulder major under thermal stress and circumferential shear stress function. , high pressure regulating pneumatic valve pneumatic valve disc and seat with mm diameter, the structure of the pneumatic valve disc, as shown in the figure guide convex shoulder size for mm x mm x mm ( High x width x thick. Pneumatic valve disc material using CrMoWVA alloy steel, in order to improve the performance of the pneumatic valve disc cavitation resistance, the surface of high temperature nitriding treatment.
and the choice of welding material and welding equipment according to adjust the working conditions of pneumatic valve, pneumatic valve disc guide convex shoulder to ensure the enough high temperature strength, and must meet certain abrasion resistance. In view of the unit repair, unable to purchase the best matching material, welding principle and material selection of references to the analysis of welding material mechanics performance, use TIG - similar to the base material R( CrMoWVTIB，Φ. Mm wire. Welding equipment using LincolnV - And argon arc welding auxiliary tools; Use the MX infrared thermometer temperature monitoring.
welding performance analysis according to the carbon equivalent formula, material is the main characteristic of CrMoWVA carbon and alloying elements is more, the weld during welding and heat treatment area prone to hardening organization, when the weldment rigidity and the joint stress is larger, easy to produce cold crack. After nitriding treatment of pneumatic valve disc, its surface hardness up to HV, easy to crack during welding.