625 is a Nickel based steel commonly used in a wide variety of oilfield applications that are suitable for high temperatures and severe corrosive environments.
625 PLUS is very similar to alloy 625, but this variation can be strengthened through precipitation hardening. 625 PLUS is used in deep sour wells where higher strengths and severe corrosion resistance is required.
625: 60,000 psi yield minimum - limited to a Rockwell C -35 maximum for compliance NACE MR-01-75/ISO 15156 (for use in hydrogen sulfide environments)
625 PLUS: 120,000 psi yield minimum - limited to a Rockwell C -43 maximum for compliance NACE MR-01-75/ISO 15156 (for use in hydrogen sulfide environments)