17-7PH Precipitation Hardening Steel Bar


17-7PH®  precipitation hardening stainless steel is austenitic-martensitic precipitation hardening stainless steel developed on the basis of 18-8CrNi, also known as controlled phase change stainless steel. The 17-7PH stainless steel is an unstable austenite structure after solid solution treatment, with good ductility and workability. After adjustment, the austenite precipitates and carbides are changed. After the martensite transformation treatment, most of the The structure transforms into low-carbon tempered martensite with better toughness. This state is the state of use of steel and has good medium temperature mechanical properties. Corrosion resistance is better than general martensitic stainless steel.


17-7PH® provides high strength and hardness, excellent fatigue properties, good corrosion resistance and minimum distortion upon heat treatment. It is easily formed in the annealed condition, then hardened to high strength levels by simple heat treatments to Conditions RH 950 and TH 1050. The exceptionally high strength of Condition CH 900 offers many advantages where limited ductility and workability are permissible. In its heat treated condition, this alloy provides exceptional mechanical properties at temperatures up to 900 °F (482 °C).

 

17-7PH is based on the 18-8CrNi developed austenite - martensitic precipitation hardened stainless steel, also known as controlled phase change stainless steel.

Solution treatment is unstable austenite, good plasticity and toughness and workability, after adjustment, so austenite precipitation carbide composition changes, and then after martensite transformation, most of the organization into toughness Better low carbon tempered martensite, this state is the use of steel, have good mechanical properties in the temperature. Corrosion resistance better than the general martensitic stainless steel.

 

17-7PH Chemical Composition:

 

C ≤0.09, 

Mn ≤1.00, 

Ni 6.50-7.75, 

Si ≤1.00, 

P ≤ 0.035, 

S ≤0.030, 

Cr: 6.00 ~ 18.00, 

Al: 0.75 ~ 1.50

 

Physical Properties:

 

Density:

(Cond. A): 0.282 lbs/in3 7.80 g/cm3

 

Electrical Resistivity:

(microhm-cm) (all conditions): 60 °F (20 °C): 80

Thermal Conductivity: BTU/hr/ft2/ft/°F (W/m•K)
At 300 °F (149 °C): 9.5 (16.5)

Mean Coefficient of Thermal Expansion: in/inl°F (µm/m•K): (Cond. A):
70 -200 °F (21 -93 °C): 8.5 x 10-5 (15.3)
70 -400 °F (21 -204 °C): 9.0 x 10-5 (16.2)
70 -600 °F (21 -315 °C): 9.5 x 10-5 (17.1)
70 -800 °F (21 -427 °C): 9.6 x 1 o-6 (16.0)


Modulus of Elasticity:

ksi (MPa)
29 x 103 (200 x 103) in tension



Magnetic Permeability:

Annealed: Weakly ferromagnetic
Heat treated: Strongly ferromagnetic

 

 

Heat Treatment:

 

TH 1050 Typical

Ultimate Tensile Strength: 180 KSI min (1240 MPa min)
Yield Strength: (0.2% Offset) 150 KSI min (1034 MPa min)
Elongation: Consult Ulbrich Technical Services
Hardness: Re 38 min

 

RH950 Typical

Ultimate Tensile Strength: 210 KSI min (1450 MPa min)
Yield Strength: (0.2 Offset) 190 KSI min (1310 MPa min)
Elongation: Consult Ulbrich Technical Services
Hardness: Re 44 min


CH900 Typical 

Ultimate Tensile Strength: 240 KSI min (1655 MPa min)
Yield Strength: (0.2% Offset) 230 KSI min (1586 MPa min)
Elongation: 1 % min
Hardness: Re 46 min (aim)