No defective product are allowed to be accepted, made and outflow.
Quality Control Process Of NSEN Valves
1. Control Of The Raw Material Quality
No acceptance of such defects as surface pores, sand holes, cracks etc.
No acceptance of the cracks, wrinkles etc. defects on the surface of forged parts.
The outlook quality shall conform to the requirements in JB/T7927, MSS SP-55 etc. standards
1.2Test Of Chemical Composition And Mechanical Performance
By means of the hand-held, direct-readout spectrograph, stretching tester, shocking tester, hardness tester etc. testing facilities to detect the material’s chemical composition and mechanical performance and, once the test is shown passed, to enter the size test process.
Test both thickness and machining allowance to see if they are correct and, if verified, enter the to-be-processed area.
2. Control Of Machining Workmanship
Aimed at the environment and medium in which every valve will be used and the client requirement, the machining workmanship will be optimized so as to let every valve highly effectively used in every kind of environment and greatly reduce the times for the valve to get failed and repaired, thus extending its life of use.
3.Machining Procedure And Quality Control
Inspection of 1+1+1 mode will be used for every procedure: self-inspection of the machining worker + random inspection of the quality controller + final inspection of the quality control manager.
Every valve is set with an unique procedure process card and manufacture and inspection in every procedure will be shown on it and kept forever.
4.Assembly, Pressure Test Control
Assembly shall not be started until every part, technical drawing, material, size and tolerance are checked without mistake by the quality inspector and will be followed with pressure test. Requirements in GB/T13927, API598, ISO5208 etc. standards will be strictly followed for valve inspection and test.
5.Surface Treatment And Packing Control
Prior to painting, the valve shall be cleaned and then, when dried, surface treated. For the machining surface of non-staining material, an inhibitor shall be coated. Primer + coating shall be made, except those clearly regulated in the order and special materials.
6.Valve Packing Control
After no falloff, wrinkle, pore are found out on the painted surface, the inspector will start binding both nameplate and certificate and then in packing count the assorted parts, check if there are files for Installation, use and maintenance, pack the channel mouth and the entire valve with dustproof plastic film so as to prevent dust and moisture from getting in during transportation and then do the packing and fixing for the inside of the wood box to prevent the goods against being damaged during transportation.