Designation by Standards

1.4542 - X5CrNiCuNb17-4-4 17-4PH SUS630 /

Chemical Composition (in weight %)

C Si Mn Cr Mo Ni V W Others
max. 0.07 max. 0.70 max. 1.50 16.00 max. 0.60 4.00 - - Cu: 3.50

1.4542 is a martensitic precipitation/age-hardening stainless steel offering high strength and hardness along with excellent corrosion resistance. It has good fabricating characteristics and can be age hardened by a single-step, low temperature treatment. It has high strength combined with good corrosion resistance in fresh and salt water, industrial and marine atmosphere, and in oxidizing chemicals. 1.4542 shows excellent resistance to oxidation up to approximately 539ºC.

It has been used for a variety of applications including oil field valve parts, chemical process equipment, aircraft fittings, fasteners, pump shafts, nuclear reactor components, gears, paper mill equipment, missile fittings, and jet engine parts.

Physical properties (avarage values) at ambient temperature
Modulus of elasticity [103 x N/mm2]: 196
Density [g/cm3]: 7.79
Thermal conductivity [W/m.K]: 15.3, 23.0 at 500oC
Electric resistivity [Ohm mm2/m]: 0.80
Specific heat capacity[J/g.K]: 0.46, 0.65 at 500oC
Transformation points: Ac(began): 590oC, Ac(finish): 770oC, Ms: 130oC, Mf: 30oC

Coefficient of Linear Thermal Expansion 10-6 oC-1

20-100oC 20-200oC 20-300oC 20-400oC 20-500oC
11.7 11.7 12.1 12.2 11.9

Solution Treatment
Heat to 1025-1055oC, then air or oil cooling. This will produce a maximum Brinell hardness of 363.

Precipitation Hardening
Temperature 480-620oC, then air cooling. Hardness after precipitation hardening is 42-32 HRC.

Precipitation Hardening Temperature (oC) vs. Hardness (HRC)

100oC 200oC 300oC 400oC 450oC 500oC 600oC 650oC
34 34 35.5 42 45.5 42.5 35 32.5

Mechanical Properties of Precipitation Hardened Steel

Temperature 0.2 % proof stress (N/mm2) Tensile strength (N/mm2) Elongation, min. (%) Reduction, min. (%) Notch impact energy (ISO-V), min. (J)
480oC 1170 1310 10 40 -
495oC 1070 1170 10 44 7
550oC 1000 1070 12 45 20
595oC 795 965 14 45 34
620oC 725 930 16 50 41
760oC 515 795 18 55 75

Hot forming temperature: 1100-900oC.

Cold Working
Despite its high initial yield strength, 17-4 can be cold worked successfully by most common methods.

Long, gummy chips characterize this alloys machinability. It can be machined in the annealed condition, however condition H1150M will yield best results. Post machining solution treatment of parts will be required prior to final hardening.

Corrosion Resistance
1.4542 has withstood corrosive attack better than any of the 400 series hardenable stainless steels, and, in most corrodents, its corrosion resistance closely approaches that of stainless types 302 and 304.

1.4542 can be satisfactorily welded by the shielded fusion and resistance welding processes. Oxyacetylene welding is not recommended, since carbon pickup in the weld may occur. When a filler metal is required, AWS E/ER630 welding consumables should be considered to provide welds with properties matching those of the base metal. When designing the weld joint, care should be exercised to avoid stress concentrators, such as sharp corners, threads, and partial-penetration welds. When high weld strength is not needed, a standard austenitic stainless filler, such as E/ER308L, should be considered.

All technical information is for reference only.