| 摘要 |
<p>There is disclosed a method of making a duplex stainless steel for an alloy having the following composition: Carbon 0.001 to 0.08 Wt.% Manganese 0.001 to 2.00 Wt.% Silicon 0.001 to 1.50 Wt.% Chromium 20.00 to 27.50 Wt.% Nickel 8.00 to 11.00 Wt.% Molybdenum 3.00 to 4.50 Wt.% Sulfur 0.0001 to 0.050 Wt.% Phosphorus 0.0001 to 0.050 Wt.% Nitrogen 0.10 to 0.30 Wt.% Iron Balance by selecting a heat treating temperature in the range of about 2050 DEG F to about 2350 DEG F to provide a desired impact toughness and a desired yield strength. There is also disclosed a duplex stainless steel having austenite pools in a ferrite matrix resulting from heating to a temperature in the range of 2050 DEG F - 2350 DEG F and cooling rapidly thereafter, said steel having essentially the above-mentioned composition with the proviso that <MATH> where: Creq = 1.5 (%Cr+%Si+%Mo) Nieq = %Ni+0,3 (%Mn) +%Cu+22(%C) +5%N and having greater impact toughness values in the cast form than Ferralium Alloy 225 and SAF 2205, the impact toughness in Charpy V-notch testing at -100 DEG F being above 75 ft.-lbs. when tested from keel blocks per ASTM E23-82, the HAZ impact toughness at -100 DEG F being above about 50 ft.-lbs. and having a yield strength of at least 65 KSI.</p> |
