Stainless steel of 17-7PH material
Thread Content
What type of stainless steel is 17-7PH?
17-7PH is an austenite-martensite precipitation-hardening stainless steel developed on the basis of 18-8CrNi, also known as a controlled phase transformation stainless steel. Chemical composition of 17-7PH: Carbon (C) ≤ 0.09, Manganese (Mn) ≤ 1.00, Nickel (Ni) 6.50–7.75, Silicon (Si) ≤ 1.00, Phosphorus (P) ≤ 0.035, Sulfur (S) ≤ 0.030, Chromium (Cr) 16.00–18.00, Aluminum (Al) 0.75–1.50
So what’s the difference from 304 stainless steel? Can it be considered 304?
No way~~ the element contents are different!! You can compare 304 with the one from floor 2!!
It is a precipitation-hardening stainless steel, and this material is commonly used for the springs in the valves of reciprocating compressors.
17-7PH is an austenite-martensite precipitation-hardening stainless steel developed on the basis of 18-8CrNi, also known as a controlled phase transformation stainless steel. After solution treatment, an unstable austenitic structure is formed, which possesses good plasticity, toughness, and workability. By adjusting the composition so that carbides precipitate from the austenite, and subsequent to a martensitic transformation, most of the structure transforms into low-carbon tempered martensite with good toughness. This state represents the practical condition for using the steel, offering excellent mechanical properties at moderate temperatures. Its corrosion resistance is superior to that of ordinary martensitic stainless steels. Chemical composition of 17-7PH: Carbon (C) ≤ 0.09, Manganese (Mn) ≤ 1.00, Nickel (Ni) 6.50–7.75, Silicon (Si) ≤ 1.00, Phosphorus (P) ≤ 0.035, Sulfur (S) ≤ 0.030, Chromium (Cr) 16.00–18.00, Aluminum (Al) 0.75–1.50. Chinese grades: 07Cr17Ni7Al, 0Cr17Ni7Al. Chemical composition: C, Si, Mn, P ≤ 0.09, ≤ 1.00, ≤ 1.00, ≤ 0.035; S, Ni, Cr, Mo ≤ 0.030, 6.50–7.75, 16.00–18.00; Cu, N, Al –, –, 0.75–1.50. American standards: ASTM S17700, AISI 631, SAE 17-7PH. Chemical composition: C, Si, Mn, P ≤ 0.09, ≤ 1.00, ≤ 1.00, ≤ 0.040; S, Ni, Cr, Mo ≤ 0.040, 6.50–7.75, 16.00–18.00; Cu, N, Al –, –, 0.75–1.50. Japanese standard: SUS631. Chemical composition: C, Si, Mn, P ≤ 0.09, ≤ 1.00, ≤ 1.00, ≤ 0.040; S, Ni, Cr, Mo ≤ 0.030, 6.50–7.75, 16.00–18.00; Cu, N, Al –, –, 0.75–1.50