The manufacture of high performance alloys requires the most sophisticated equipment and highest level of expert knowledge in the metals industry. Alloying, refining, hot working, cold working, and associated quality control are done by strictly defined and monitored procedures to ensure that finished products meet exacting performance standards.
The initial alloying is one of the most critical production steps. The alloys may require control of over fifteen chemical elements. Some of those elements may need to be added as precisely as 0.05% variation in target quantity. Others may need to be excluded to miniscule limits expressed in ten thousandths of one percent. Alloying methods span the range of modern technology in melting, precision remelting, and powder metallurgy. Alloys requiring the highest compositional and microstructural control, such as those used in nuclear and gas turbine applications, are first melted under vacuum and then refined by remelting either under vacuum or under controlled slag flux or they are created by powder metallurgy.
Hot working on rolling mills, forges, or presses is used to shape ingots and billets and to give the metal a uniform, wrought structure. Powerful equipment is required since many of the alloys are inherently strong at high temperatures.
Finished shapes and sizes are produced by cold working. Sheet and strip are produced on rolling mills, while rod, bar, and tubing are cold finished on draw benches. Tubing is also cold worked on rotating-die, Pilger mills. Cold working can be done to extremely close tolerances.
Because of the critical applications for high-performance alloys, the quality systems that monitor and control all manufacturing operations are the most detailed and rigorously applied in the metals industry. Statistical process control and total quality management are often integral parts of the quality systems. In many cases, the quality systems are audited and certified by national and international organizations such as ASTM, ASME, ISO and TUV. Quality control includes extensive laboratory facilities and state-of-the-art nondestructive testing including ultrasonic and eddy current equipment.