17-4 PH 630 1.4542 Corrosion Resistance

17-4PH stainless steel has excellent corrosion resistance. Corrosion tests and service experience have shown that in all aged conditions it is superior to standard hardenable stainless steel grades such as 420<, 431 and 410. Its corrosion resistance is comparable to grade 304 Stainless.

Alloy 17-4 PH withstands corrosive attacks better than any of the standard hardenable stainless steel and is comparable to Alloy 304 in most media.

If there are potential risks of stress corrosion cracking, the higher aging temperature then must be selected over 1022°F (550°C), preferably 1094°F (590°C). 1022°F (550°C) is the optimum tempering temperature in chloride media. 1094°F (590°C) is the optimum tempering temperature in H2S media.

The alloy is subject to crevice corrosion or pitting corrosion attack if exposed to stagnant seawater for any length of time. It is corrosion resistant in some chemical, petroleum, paper, dairy and food processing industries (equivalent to 304L grade).