Description

17-7 PH stainless steel is a precipitation-hardening stainless steel. SS 17-7 offers good corrosion resistance, good formability, and high strength therefore has been used for aerospace applications.

Composition

17-7 PH stainless steel includes high levels of chromium, nickel and aluminum. In addition to these elements, iron makes up the bulk of the steel’s composition. Carbon, manganese, phosphorus, sulfur and silicon may also be present in trace amounts, not exceeding 1 percent of the compositional total. 

Physical Properties
Melting Point: 2550 – 2640°F (1400 – 1450°C)
Density: 0.282 lbs/in3 / 7.8 g/cm3
Modulus of Elasticity in Tension (RH 950 & TH 1050): 29.6 X 106 psi / 204 GPa

Mechanical Properties

Condition: Annealed Tensile Strength Minimum (psi): 130,000
Yield Strength Minimum 0.2% offset (psi): 40,000
% Elongation in 2” Typical: 35%
Hardness: Rockwell B85

Condition: Hardened + Aged (TH1050) Tensile Strength Typical (psi): 200,000
Yield Strength Typical 2% offset (psi): 185,000
% Elongation in 2″: 9%
Hardness: Rockwell C40

Condition: Hardened, Cryogenic Quench + Aged (RH950) Tensile Strength Typical (psi): 235,000
Yield Strength Typical 2% offset (psi): 220,000
% Elongation in 2″: 6%
Hardness: Rockwell C48

Condition: Cold Rolled/Worked + Aged (CH900) Tensile Strength Typical (psi): 265,000
Yield Strength Typical 2% offset (psi): 260,000
% Elongation in 2″: 2%
Hardness: Rockwell C49

Heat Treatment

This material requires three essential steps in heat treating:
 1) Austenite conditioning.
 2) Cooling to transform the austenite to martensite.
 3) Precipitation hardening to Condition TH 1050 or RH 950.

To obtain the highest mechanical properties from the alloy, Condition A material is transformed to martensite the mill by cold reduction to Condition C. Hardening to Condition CH 900 is accomplished with a single, low-temperature heat treatment.

Corrosion Resistance

Corrosion resistance in Condition TH 1050 and RH 950 is generally superior to that of the standard hardenable chromium types of stainless steel such as Types 410, 420 and 431, but is not quite as good as chromium-nickel Type 304. Corrosion resistance in Condition CH 900 approaches that of Type 304 in most environments.

Formability
In Condition A, the alloy can be formed comparably to Type 301. It work hardens rapidly and may require intermediate annealing in deep drawing or in forming intricate parts. Springback is similar to that of Type 301. This alloy is extremely hard and strong in Condition C. Therefore, fabrication techniques for such material must be used.

Weldability
The precipitation hardening class of stainless steel is generally considered to be weldable by the common fusion and resistance techniques. Special consideration is required to achieve optimum mechanical properties by considering the best heat-treated conditions in which to weld and which heat treatments should follow welding. This particular alloy is generally considered to have poorer weldability compared to the most common alloy of this stainless class, 17-4 PH stainless steel. A major difference is the high Al content of this alloy, which degrades penetration and enhances weld slag formation during arc welding. Also, the austenite conditioning and precipitation hardening heat treatments are both required after welding to achieve high strength levels. When a weld filler is needed, 17-7 PH is most often specified.

Royal Emperor Metals & Supply is a leading supplier of quality 17-7 Stainless Steel Sheet, 17-7 Stainless Steel Plate, 17-7 Stainless Steel Bar, 17-7 Stainless Steel Forged Bar.

All of our 17-7 PH stainless steel and stainless steel plate is ordered to specific thickness. We supply 17-7 PH stainless steel and 17-7 PH stainless steel plate and are capable of fulfilling your required lengths and widths. Royal Emperor Metals & Supply Inc. also has a stocking program to support long term contract for your 17-7 PH stainless steel needs.