17-4PH / 630 / 1.4542 is one of the most popular and most commonly used stainless chromium-nickel alloy steels with copper additive, precipitation hardened with martensitic structure. It is characterized by high corrosion resistance while maintaining high strength properties, including hardness. Steel can operate in the temperature range from -29 ℃ to 343 ℃, while retaining relatively good parameters. In addition, the materials in this grade are characterized by relatively good ductility and their corrosion resistance is comparable to 1.4301 / X5CrNi18-10.

Chemical Composition



AISI 17-4PH1.4542630


1. High-level cleanliness and finer microstructure through ESR.
2. 1.2083 (ESR) already process quenching and tempering heat treatment first before dispatching from the factory in order to reduce customer’s cost.
3. Good corrosion resistance:Suitable in the plastics and mirror mould
4. Good wearability:The best range of hardness is HRC50-52.
5. The surface is similar to mirror after grind.


17-4PH, 630 and X5CrNiCuNb16-4 / 1.4542 is provided in the form of round bars, sheets, flat bars and cold-rolled strip. The material is widely used in the aerospace, marine, paper, energy, offshore and food industries for heavy-duty machine components, bushings, turbine blades, couplings, screws, drive shafts, nuts, measuring devices.

Corrssion Resistance

The corrosion resistance of Type 17-4PH / 630 is comparable to that of Type 304 Stainless Steel in most media and superior to that of the hardenable 400 series stainless steels. Refer to NACE (National Association of Corrosion Engineers) for recommendations.

Heat Resistance

Grade 630 stainless steels have good resistance to oxidation. However, long-time exposure of grade 630 to temperatures of 370 to 480°C should be avoided, to prevent loss of toughness at ambient temperature. These grades should not be used at temperatures above age-hardening temperature, to avoid reduction of hardness and mechanical properties of the metal.


Grade 630 stainless steels can be welded using all conventional methods, and they do not require pre-heating. Care should be taken in designing and welding of high strength steels to prevent weldment stresses.


Grade 630 stainless steels can be machined in their solution-treated condition. They have machining rates similar to that of grade 304 steels.

Heat Treatment

Solution treatment (Condition A) — Grade 630 stainless steels are heated at 1040°C for 0.5 h, then air-cooled to 30°C. Small sections of these grades can be oil quenched.
Hardening — Grade 630 stainless steels are age-hardened at low temperatures to achieve the required mechanical properties. During the process, superficial discoloration occurs followed by shrinkage at 0.10% for condition H1150, and 0.05% for condition H900.