Ball and seat assemblies will be additionally inspected according to the following:
1, Ball and seat assemblies will be vacuum tested 100%, with dry sealing surfaces, at 19in.Hg miniumu vacuum with no leakage for a minimum of 3 seconeds after vacuum source is isolated.
2, Ball hardness will be certified with a certification accompanying each lot of material.
| Pump materials for Balls and Seats | |||
| Symbol | Description | Hardness | Material |
| A1 | Stainless Steel | Ball:HRC58-65 | UNS 41000-UNS44000 |
| Seat:HRC52-56 | |||
| B1 | Cobalt Alloy,Cast | Ball:HRC56-63 | Cobalt,chromium,and |
| Seat:HRC50-56 | tungsten alloy | ||
| B2 | Cobalt Alloy, Powder | Ball:HRC53-60 | Cobalt,chromium,and |
| Metal | Seat:HRC51-57 | tungsten alloy | |
| C1 | Tungsten Carbide | Ball: HRA88-89 | tungsten with Cobalt |
| Seat:HRA88-89.5 | binder | ||
| C2 | Nickel Carbide | Ball:HRA89-90.5 | Tungsten with Nickel |
| Seat:HRA87.5-89 | binder | ||
| C3 | Titanium Carbide | Ball:HRA89-90.5 | Tungsten and tianium |
| Seat:HRA89-90.5 | carbide with cobalt | ||
