We ordered a batch of open-die forged shafts for our mining conveyor system. The first month of operation showed consistent performance under full load. The grain flow on the shaft surface was uniform, and we measured no deviation in straightness after the initial run-in period. The induction-hardened bearing journals held their hardness within spec, and the vertical tempering process eliminated the distortion we used to see with horizontal furnaces.
What stood out was the fatigue resistance during start-stop cycles. Our previous shafts from another supplier developed micro-cracks after three weeks. These shafts showed no signs of surface fatigue after four weeks of continuous use. The documentation provided with each shaft included actual hardness traverse curves and ultrasonic test reports, which made our quality audit straightforward.
One area for improvement: the lead time for the first batch was longer than quoted. However, the technical support team explained the additional inspection steps, and the second batch arrived on schedule. For heavy shaft applications where failure is not an option, this level of process control justifies the wait.