Inconel hog-out

The challenge of material integrity, unique design features, and tight tolerances.

In many manufacturing processes, the manufacturer has to take into account the unique properties of the material to maintain (or improve on) the integrity of the source material. Other times, manufacturers have to come up with creative ways to create the unique features of the design of a part. And of course, tolerances are more critical in some applications, depending on how the part interacts with other parts in the customer’s operation.

In many manufacturing processes, a higher priority of one is given over the other two, but sometimes, a part comes along where all three are of critical importance. Inconel hog-out is one of those parts. It’s a down hole device used in the oil and gas drilling industry for pumping oil to the surface – what in the industry is called “artificial lift”. The manufacturing challenge is similar to the challenge in manufacturing parts for aerospace, especially those parts made with stainless and high temp alloys such as Inconel.

The Manufacturing Challenge

Material: The inconel hog-out is made from 410 Stainless Steel or Inconel 625. Both are not considered “free-machining” alloys. Inconel, especially, develops high temperatures during machining operations that alter the alloy microstructure, and potentially induce residual stresses that can degrade fatigue life of the component and/or distort the final geometry.

Design Features: Varying cross section from thick to thin requiring large amounts of material removal and potential distortion from stress relieving.

Tolerances: True position and size tolerance of the holes are both less than .001 inches – exacerbated by their location on the end of the thin sectioned wings, which is where heat and distortion from prior operations will have maximum impact.

Our customer’s previous supplier just couldn’t get the tolerances right. Specifically, they had an issue with the hole location and size requirements.

By the time LeanWerks was introduced to this part, the customer had low expectations as prior suppliers had not found a way to successfully address these challenges. Previous manufacturers forced the customer to compromise some objectives because the parent assembly did not fit together with the designed fit through the tight tolerance holes in the thrust brace. The customer had two options: 1) relax the tolerance on the holes and sacrifice design performance, or 2) buy extra inconel hog-out and conduct time consuming and expensive sorting activities to best fit each thrust brace with each assembly.