STAINLESS STEEL TUBE & PIPE   

Alloy 17-4 PH is a precipitation hardening martensitic stainless steel with Cu and Nb/Cb additions. The grade combines high strength, hardness (up to 300°C / 572°F) and corrosion resistance, combining high strength and post heat treatment hardness with excellent corrosion resistance that, in tests, proved superior to standard grades such as 420, 431 and 410. In fact, the corrosion resistance of 17-4PH is comparable with that of Grade 304.

Mechanical properties can be optimized with heat treatment. Very high yield strength up to 1100-1300 MPa (160-190 ksi) can be achieved. The grade should not be used at temperatures above 300°C (572°F) or at very low temperatures. It has adequate resistance to atmospheric corrosion or in diluted acids or salts where its corrosion resistance is equivalent to grade 304 or 430. chromium-copper stainless steel standardised as UNS S17400, 17-4PH is highly resistant to stress corrosion, has good machinability, short-term, low temperature heat treatments that minimise warpage and scaling, and is considered to be more cost effective than many high nickel non-ferrous alloys.

Due to the high strength of 17-4PH, its main use is in aerospace and other high technology industries such as offshore, in gears, valves, turbine blades, nuclear waste casks, moulding dies and shafts, as well as having been tested in the petrochemical, petroleum, paper, dairy and food processing industries, and in such applications as boat shafting. The unique combination of properties within 17-4PH makes this alloy an effective solution to many design and production problems.

17-4PH is a precipitation hardening martensitic stainless steel, which combines high strength and hardness (after heat treatment) wich excellent corrosion resistance, and is suitable for easy fabrication.

Solution Annealing
As supplied 17-4PH is usuall in the solution treated condition (Condition A). It can be heat treated at different temperatures to offer a wide range of properties. (We also hold stock in H1150+H1150, and annealed block).

Typical Mechanical Properties (longitudinal)

Corrosion Resistance
17-4PH stainless steel has excellent corrosion resistance. Corrosion tests and service experience have shown that in all aged conditions it is superior to standard hardenable stainless steel grades such as 420, 431 and 410. Its corrosion resistance is comparable to grade 304 Stainless.

Welding
Arc and resistance welding processes used on standard grades of stainless steel are applicable to 17-4PH stainless steel. The low hardness enables sections, up to 100mm, to be welded without requiring pre heating.

Fabrication
17-4PH Condition is suitable for limited cold forming, H1100, H1150 and overaged conditions are more suitable when severe cold forming is required.

Machining
17-4PH Condition has machining characteristics similar to stainless grades 302, 304 and 410. The high hardness and strength in Condition H900 is the most difficult to machine and the material should be machined at 60% of the rate which is used for Condition A.

Nitriding
To increase the resistance to surface wear, with a slight decrease in corrosion resistance, 17-4PH stainless steel can be nitrided. An approximate hardness of 64/67HRc can be achieved, with a surface hardness depth of up to 0.15mm when nitrided at 540°C, while still maintaining a high core strength.