Mystery solved

As reported last week, while conducting some dumbbell testing, we found a puzzling discrepancy with the mechanical strength testing of the superalloys we are using to make the turbine blades.

Although the superalloys had passed certification, we decided to use our full non-destructive testing program to find the source of the issue, which was not, as we had suspected, anything to do with the process of chopping up the as-supplied cast billets into smaller pieces. So it wasn’t a question of our damaging the surface of the material and contaminating it with the wire eroder used for cutting.

In fact, the problem turned out to be simply that the temperature of the block mould for the blades wasn’t held where it should be, which resulted in the material being cooled too quickly when it was cast, creating the equivalent of a weld line within the parts that gave it a weakness and caused it to fail the test.

In a fairly short time we managed to get the process under control. Now we know our non-destructive testing methods work, and we can cast some more dumbbells with the correct process controls in place and repeat the tensile tests to clear ourselves for turbine blade production.

Even more testing processes locked down and ready to go

We intend to individually inspect every single turbine blade we make to show it is defect free using the full CT scanning process we have mapped out, and demonstrate that the composition is correct, and the materials are doing what they should be doing.

Very first finished GT50 turbine disc manufactured

Just last week we were cutting the final fir tree roots into the turbine disc – now this is complete and looking beautiful, along with the curvic coupling, the labyrinth seals and the backstop that receives the locking plate to hold the blades in position. All the manufacturing processes are completed and it’s just waiting for inspection and then it will be ready for the blades. So big progress here!