AboutJavad Mola Expertise I welcome questions related to physical metallurgy of steels preferably stainless steels.
Experience As a PhD candidate at Graduate Institute of Ferrous Technology (GIFT), I am working on the formability of stainless steel sheets.
Organizations Graduate Institute of Ferrous Technology affiliated to Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea. Pohang is home to POSCO, the third largest steel company in the world.
Publications Solid State Phenomena, Materials Science and Technology
Education/Credentials BS degree in Materials Engineering earned from Isfahan University of Technology, Isfahan, Iran. MS degree in Materials Science and Engineering earned from Sharif University of Technology, Tehran, Iran. Currently PhD candidate at Graduate Institute of Ferrous Technology (GIFT), Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
Question i want to draw ss200 series up dia 0.03mm(49swg) and i do not want magnetism to appear in the final drawn wire.as even the 200 series is austenitic therefore non magnetic,but due to cold working magnetism can appear..pls advise which grade in the ss200 series should i use and which will be the best alternative to remove the magnetism...currently im buying nonmagnetic ss304 in 0.03mmdia.and i am planning to set up my production unit.
The strain-induced martensitic transformation (austenite to martensite transformation as a result of cold deformation) can be avoided if the Md30 temperature is far below the room temperature. For your information, Md30 temperature is the temperature at which application of 30% of true strain results in the transformation of 50% of the austenite to martensite (so Md30 is invariably above the Ms temperature). Now, if you look for a 200 series alternative for 201, you have to make sure that the Md30 temperature is low enough. The following empirical relationships could be used to calculate Md30 in austenitic stainless steels (concentrations must be in mass percent):
As you can see in both formulae, Md30 temperature can be manipulated by changing the composition. In your case depending on the N and C content of the 201 you used, Md30 could have been from far below the room temperature to about the room temperature. One of your solutions could be to switch to a grade with a higher Mn, N, and C contents like 205 whose composition along with that of 202 and 205 is tabulated in the attachment. In view of the Md30 temperature indeed, C and N contents close to the upper limits could therefore help. In view of the corrosion resistance however, C contents close to the minimum limit are more desirable since the formation of chromium carbides (which under certain processing conditions may form a Cr-depleted layer in their vicinity) is less likely.
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