Continuous improvements in our production methods and continous capital investments in new equipment and in production technologies make Johnson Metall a leading supplier of casted brass- and bronze alloys. Our plants are always utilising the latest technologies to obtain the highest quality and most cost-efficient products available.
Brass alloys are melted in modern induction furnaces. Raw materials consist of brass ingots bought to specification from external suppliers, and resirculated metal from our own production. Certain metals (Cu, Zn, Al) may have to be added to acchieve the correct specification.
The induction furnaces create a good circulation of the melt, whereby slag particles float to the top of the furnace and can be removed. In addition, the melt is degassed before pouring, to remove air-bubbles.
Metal composition of every melt is analyzed by spark spectrophotometer and eventually corrected before pouring.
Our furnaces batch up to 4500 Kilos.
Johnson Metall Group has continous casting processes inhouse for both brass- and bronze alloys. A continuous feeding of molten metal is entering a die to precise dimensions, and a cooling system provided uniform and controlled solidification. Automatic saw systems ensure cutting into defined lengths. Typical product dimensions are ranging from 50-120mm OD. The methos ensures castings of high quality with a limited surplus for further machining of products to tigh tolerances. The high quality of the castings is caused by the a controlled cooling process and a technology that enables the castings to form from material from the inner section of the molten metal free of slags and oxides.
Brass alloys are produced in-house utilizing the centrifugal casting process. By this process a circular mould is rotated at high speeds. Molten metal is poured into the spinning mould and exposed to high G-forces while solidifying. The metal solidifies from the surface of the mould inwards, thereby allowing air-bubbles and light-weight particles (slag) to distribute on the inner surface of the casting.
Due to the high G-forces, defects in casting from solidification shrinkage are not present (as with sand-castings). Impurities can be removed by machining the inner surface of the casting. The outer surface of the casting gets a fast solidification and different metal structure, it is therefore also removed in subsequent machining.
In the center part of the casted tube, we obtain a uniform, dense, sound casting, suitable for machining for various components.
Our centrifugal casting machines are used for manufacturing tube-diameters from 110-2100 mm (3-83 inch.), whereas smaller diameters are manufactured by continous casting.
Many decades of experience in house tool making and machining processes ensures high quality of the final product.
• Horizontal or vertical
• Automated, up to 3 m length
• 10 mm metal removed for quality reasons
• Dry process
• Wet process
• High accuracy
• Several rings finished in one operation
• 5 axes
• 0-1250 mm diameter
• 5 axes
• angular drilling
All deburring are made by the industrial robots giving not only good quality, but also the best repeatability. For certain products, vibrational deburring is used in addition to the robotional deburring.