Ball valve production technology
Despite the widespread use of ball valves in everyday life and production, not everyone represents the technological process for the manufacture of these popular valves.
Let's look at this in more detail using the example of products manufactured by S.T.A. ball valves for water with coupling threaded connections 15, 20, 25, 32, 40 and 50mm. The most difficult thing in the manufacture of a ball valve is the production of a body with its complex machining geometry.
The best option is hot stamping of brass in a special high-strength die-form - in this case, a solid billet with finished outer surfaces is obtained, which practically does not require machining, except for descaling. It is this method of production of ball valve bodies that is used by S.T.A. - it allows you to get the most durable part due to the compaction of brass during stamping with minimal deviations from a given shape and maximum savings in brass. A less reliable method is conventional casting or powder metallurgy. The first has a long history and a high probability of the occurrence of shells in the body of the workpiece, the worst quality of its surface due to the rough mold for casting and, as a result, the cost of additional machining. The second one is more modern and is similar to hot stamping - there is also an exact matrix in which brass powder is baked, but the mechanical strength of the product is lower due to the weaker connection of metal particles to each other. As a rule, this method is used for the production of cheap cranes from various alloys. The shut-off ball in ball valves for water is made on CNC machines, as a rule, it is polished steel with a nickel coating to reduce friction and increase corrosion resistance, although in some cases it can be made of brass (taps for gas) or stainless steel (for food and chemical industry).
The control rod is also made of steel with subsequent nickel plating, although in some cases it and the stem clamping nut are made of brass on semi-automatic machines. After cleaning the surfaces of the parts of the body of the ball valve, they are subjected to nickel plating and machining on CNC machines.
This is a very responsible procedure, since the tightness of the ball valve and its stable operation will depend on its accuracy. Assembly of ball valves at S.T.A.
is performed in the following order: - a control rod with a fluoroplastic sealing ring is inserted into the main body of the valve from the inside - this is an important feature that distinguishes ball valves from other types of valves and does not allow pressure to squeeze the stem out of the body, and also contributes to self-sealing of the stem when pressure increases.
splined connection adhesive-sealant, which prevents spontaneous unscrewing and loss of tightness by a ball valve. - then the clamping nut of the stem is tightened and the control knob is installed.
- after assembly, all valves are tested for tightness under pressure in a special bath, after which they are dried, packaged and they can be shipped to the next consumer.
If you have any questions about the production, range or quality of ball valves produced by our company, please send a message on the feedback page Contacts