Gunmetal
KEMPER gunmetal - suitable for all kinds of drinking water

Old bronze ship's bells, artistic wine casks and other finds from the Bronze Age (from approx. 6000 BC.) impressively prove this materials unusual durability. And that's still true when the witnesses of this creative epoch have been laying in salty sea water for thousands of years. The gunmetal cast by KEMPER is a material closely related to bronze (copper and tin) and is extremely suited for use in domestic water engineering, especially in drinking water and heating installations.
Gunmetal Rg5 - CC499K
Gunmetal is a valve and plumbing material standardised in accordance with DIN 50930-6 / DIN EN 1982 that, with its diversified applications is especially suited to sanitary installation engineering, e.g. as a valve material for stop, securing and regulating valves, as fitting material for pipe-system components and as a construction material in water, filtering and recycling engineering.
Components made of gunmetal
The quality of copper, together with the hygiene of tin, the easier processing of lead and the low proportion of the reactive zinc has led to gunmetal being used in many areas in life. The close relationship to bronze – gunmetal is also referred to as multi-component bronze – characterises the main attributes of this alloy. The corrosion resistance of gunmetal is especially important. Gunmetal is corrosion resistant against the corrosion forms often found in drinking water, dezincification and stress-crack corrosion. The multitude of applications result from that.

Excellent material properties
With its outstanding material characteristics, the use of gunmetal ranges from drinking water through aggressive seawater and on up to process water. In the same way, petrochemical, dye and paint products along with gasses and liquid gasses are conducted through components made from this material. At the same time, the material allows operational temperatures of – 176 °C to + 225 °C. That is because the gunmetal itself underlies nearly no measurable embrittlement even at such low temperatures. For that reason, the material is also preferably used as a valve material in gas liquefaction. Even such critical, liquefied gasses such as oxygen, nitrogen etc. are safely conducted, distributed and blocked through valves made of gunmetal at approx. – 176 °C.
Benefits at a glance
- Due to its high Cu content, gunmetal has low dezincification
- According to the Drinking Water Ordinance, gunmetal can be used without restrictions in all water qualities
- Gunmetal can be used unrestricted according to all standards
- (50930-6, DIN 1988 etc.)
- Gunmetal is especially corrosion resistant
- Gunmetal is collected from recycling materials (old valves and components) without any loss of quality, protecting the environment and conserving resources
- That means gunmetal provides you with security! Now and in the future!
New ‘Rg+’ alloy
Sometimes less is more. Which is the case with our new lead-free ‘Rg+’ alloy. This is a real milestone, which further increases the health and safety of people and has less environmental impact. All achieved without losing the outstanding characteristics, as Rg+ can be cast almost like Rg5 because it has identical mechanical characteristics. Another advantage is that existing models can be taken over – as can processing tools and tensioning devices used for current articles. Furthermore, Rg+ has comparable machining properties. The resistance to corrosion and dezincification are not only identical, they even partially outperform the original containing lead. The new alloy can be used as low as -176 degrees Celsius – without the risk of embrittlement in cold conditions.
Rg+ is approved on the German ‘UBA-Positivliste’ that is published by the German Environment Agency and certified to DIN SPEC 2701 with reference to the German Drinking Water Directive. We meet all of the requirements of REACH and RoHS with this alloy.
Material comparison Rg5 to Rg+
- Rg+ is cast almost identically Rg5
- Rg+ has identical mechanical properties as Rg5
- existing models can be taken over
- processing tools and tensioning devices can be used for current articles
- comparable machining properties
- The resistance to corrosion and dezincification are not only identical, they even partially as Rg5
- can be used as low as -176 degrees Celsius without cold conditions