New powdered material with extreme properties
01.03.2018 | Andreas Weseler

The name of the “wonder material” sounds quite unspectacular: 72HA. Behind the short form name hides an iron-based powder metallurgical alloy with high carbon and chromium contents. Its chemical composition guarantees excellent wear resistance against abrasion and corrosion. But not only that: The dual-stage manufacturing process from parts made from 72HA also makes machining substantially easier. 

In the first step, the blanks are formed during the HIP process. HIP stands for hot isostatic pressing – in a heated pressure vessel, the powder mixture is simultaneously pressed and sintered. The workpiece generated by this process stands out thanks to its high material density but does not yet have the desired final strength for the finished part. It is easy to work with the workpiece while it is still in this soft state. It is not hardened until afterward. The iron base of 72HA makes this process possible.

Last but not least, the production process meets the special bushing requirements for the ZE BluePower series. These sleeves have a special elliptical shape. Producing this shape in conventional manu facturing is a demanding task, but it has a lot of advantages. First of all, it enables optimized positioning of the cooling and heating cartridge holes and thus effective tempering of the housing elements.  In addition, the oval geometry prevents bushing collapse in the gusset area. This facilitates heat transfer from the outer body to the bushing. The bushing is also axially secured in the housing by a special collar. This prevents leaks at the sealing surfaces of the barrel connections that could otherwise occur without axial securing due to differences in thermal expansion between the bushing and the outer body. “We can use the new metallic material to manufacture the complex geometry of the completely through- hardened bushings without any problems,” Madle says in praise.