What's the difference between the two kind of stainless steel? I will be greatful if you can tell me the mechanical property and the application scop of the materials.
2006-12-04 14:38:33 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Engineering
Type 304 - One of the most widely used and oldest of the stainless steels. This was originally called 18-8 which stood for its chromium and nickel content. It possesses an excellent combination of strength, corrosion resistance and fabricability.
Type 17-4PH - General purpose, precipitation-hardening stainless steel, Low temperature (1000 deg F approx) “age hardening” produces superior hardness/strength without distortion or scaling.
2006-12-04 14:45:27 · answer #1 · answered by DanE 7 · 0⤊ 0⤋
18-8 refers to 18 weight percent Nickel, 8 weight percent Chromium. The same goes for 17-4.
I think the 18-8 steel is austenitic (corrosion resistant), while the 17-4 is used as a martensitic steel and precipitation strengthened (higher strength) .
Austenite (gamma) is a phase of iron which is FCC (Face Centered Cubic), and more corrosion resistant than the regular ferrite (alpha) phase, which is BCC (Body Centered Cubic). Martensite is a BCT (Body Centered Tetragonal) phase that can be created with very rapid cooling, and is very high strength.
2006-12-04 14:45:01 · answer #2 · answered by fletchermse 2 · 0⤊ 0⤋