Official Answer
Answer
In hazardous environments (e.g., oil refineries, grain silos), sparking from steel components is a major fire risk. Phosphor Bronze (Grade C51000) is specified for spiral rings in these cases because it is non-sparking and non-magnetic. While its tensile strength (approx 100 ksi) is lower than carbon steel or 17-7PH, its excellent corrosion resistance and fatigue life make it suitable for electrical and marine components. Designers must account for the lower Modulus ($E \approx 16 \times 10^6$ psi), which results in a lower centrifugal speed limit and reduced thrust capacity compared to steel counterparts.
