About Grade 4|The strongest commercially pure titanium (80 KSI yield). Highest oxygen content of the CP grades, which is what provides the strength increase. Same excellent corrosion resistance. Used for marine hardware, chemical processing, and high-strength fasteners where alloy titanium's cost isn't justified. Machines slightly harder than
Grade 2 due to the higher strength. Compare to Grade 2 (weaker, more common) and
Grade 5 (alloy titanium, significantly stronger).