The increased price for nickel has negatively impacted the cost of high nickel-based alloys, such as Alloy 625 (UNS N06625). This increase has created major challenges for companies trying to reduce spending on raw materials. The austenitic nickel-chromium alloy, characterized by extremely good corrosion resistance in environments with widely varying acidic and chloride present, are in many ways the last resort in critical applications making it impossible to replace them with cheaper stainless steels.
As a material substitution is not viable the easiest method to reduce material spending is to reduce the actual material needed or in other words to arrive closer to the final shape of the component. Here Near-Net Hot Isostatic Pressing (NNS HIP) can play a major part in providing a solution. As one of the main advantages with PM HIP is the ability to produce irregular shapes and complex geometries without the need for excessive post-machining.
“As nickel alloy material prices have increased, we have seen an increased surge to use PM HIP to produce raw material blanks closer to the final geometry. Customers are unsatisfied at paying for material that they are ultimately removing during the machining and therefore are exploring the use of NNS HIP in new areas”. Commented Erik Salomonsson, Technical Sales Engineer at MTC Powder Solutions.
While manufacturing methods such as forging are often cost effective for simpler geometries the method’s restrictions to produce more complex shapes can often result in the need for larger material blanks than are necessary. One example of this would be a one-piece forged valve body which has substantial increasing material costs. On larger choke bodies produced by closed die forging integrating bores are also an example where increased material is needed as the bores need to be drilled out at the machining stage presenting a challenge to keep costs down.
With NNS HIP, valve and choke bodies, can be produced with integrated bores and closer to the final shape. This supports the reduction in the material needed and consequently the cost of your high nickel alloy components is also reduced!