Tyre valves for cars and trucks are safety parts. The basic brass material combined with rubber coating for the valve material has proven itself for decades. The reasons for this are:
- good corrosion resistance
- no low-temperature embrittlement
- high mechanical strength with good ductility
- good processing properties
- good coating properties (rubber vulcanisation)
In practice there are three main manufacturing processes:
Backward extrusion (hot forming)
This method is mainly used for larger valves, e.g. truck valves. For valves that are only hot formed and machined, we recommend the alloy Wieland-Z48 (CuZn40Pb2). The alloy Wieland-Z29 (CuZn39Pb2) has a higher copper content and therefore allows a larger bending angle for valves (for subsequent bending). In order to achieve a high level of accurate processing, Wieland hot forging rods offer outstanding advantages in terms of the reliability of processing properties.
Machining of solid rods
For this purpose we recommend Wieland-Z33 (CuZn39Pb3). The halfhard Wieland-Z21 (CuZn38Pb2) alloy is recommended for valves that are essentially cold formed subsequent to machining. Wieland keeps a large variety of sizes of each in stock. Wieland 5000 rods are ideal for machining:
Cold heading
For valves which are cold headed and then machined we offer a specially developed alloy Wieland-ZB4(CuZn36Pb3) with very good cold working properties and high material stability.
