Failure Analysis valve, the valve during use, will inevitably fail. Therefore, how to improve the life of the valve, the valve to malfunction occurred in the operation to make accurate judgments and effective treatment is an important means to ensure safety in production running smoothly. In all sectors of the production run with a valve failure analysis, the use of welding, cutting, grinding, valve maintenance, cost savings for businesses significant effect.
defects.
Tightness test is to detect the opening and closing member and the sealing tightness test.
Fourth, the sealing surface maintenance
1, sealing surface grinding repair
Grinding the sealing surface, usually hand-grinding, it can also be used with a grinding mill or grinder and lathe with.
Grinding principle: between two opposing joint surface grinding cast abrasives, then maintain a certain pressure between the two binding surfaces, along a certain axis of rotation center, combined with the elimination of injustice at the surface, so that the valve head and seat between the contacting surfaces to achieve proper contact and a certain smoothness, can achieve such a tight binding.
1.1, ground check before. According to the degree of damage to the sealing surface, using different polishing method, when the sealing surface defects (scratches, crushed, pits, pitting scars, etc.) wear when 0.005-0.05mm, by abrasive grinding. When the depth is greater than 0.05mm, after coarse sandpaper, then abrasive grinding. When the damage is severe, cold welding repair of the defect site, and then re-cut grinding.
1.2 abrasive grinding. The sealing material and the extent of the defect, the correct selection of the abrasive. Commonly used abrasives are silicon carbide, boron carbide, aluminum oxide, corundum powder, diamond powder.
1.3, grinding precautions.
1.3.1, when the lapping gently to prevent the sealing surface gouges.
1.3.2, ground to a uniform pressure should not be too large. Coarsely ground pressure can be larger, lapping should be small.
1.3.3 After grinding some time to check the flatness of the workpiece.
1.4, the grinding process.
1.4.1 kibble: No. 1 No. 0 sandpaper to pitting, or removed by bumps. It should be painted before the kibble Hongdan color printing checks, based on the case of color printing mill, grinding another job is low. To eliminate the traces of the sealing surface, higher flatness and must finish;
1.4.2, finely ground: valve and valve seat after coarse grinding, coloring print inspection, if found and around thin and uniform contact line, on the research polishing. Use red lead powder (lead tetroxide) Check the joint surface defect to the situation. Typically the valve sealing surface to be ground several times to be successful until the entire surface of the seal ring continuously and reached a certain width. Achieve a high quality finish, so as to achieve the sealing requirements. |
