Schaeffler diagram

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The Schaeffler diagram is a method for determining the structure in materials science and was developed by Anton L. Schaeffler in 1949 and named after him.

With the help of the chromium and nickel equivalents , which form the abscissa and ordinate of the diagram, points can be displayed in the diagram for steels and cast iron . The nickel equivalent is calculated from the mass proportions of the alloying elements which, in the case of iron, lead to austenite being contained in the structure. The chromium equivalent stands for the effectiveness of the ferrite-forming elements . The Schäffler diagram is divided into different areas that represent the structure at hand. In addition, areas are shown in which problems can occur when welding the material. These areas are labeled with the corresponding vulnerability. A point can be drawn in the Schaeffler diagram for each material. Depending on the position of the point, conclusions can be drawn about weldability and the existing structure.

The structures that are in the "white" area of ​​the Schaeffler diagram are best suited for welding. The white area has the shape of an S and is in the middle at the bottom. In this area there are no problems such as hot cracks , cold cracks , grain growth and sigma embrittlement.

When welding two different base materials, the final weld metal structure can be determined graphically in the Schaeffler diagram and even manipulated with the selection of the filler material (please note the computer under the web links). The graphical determination of the resulting weld metal structure takes place in three steps: 1) Draw the position of the two base materials and connect them to a straight line 2) Draw the midpoint of the line between the two base materials 3) Draw the position of the filler metal and connect this point with the midpoint shown under 2) 4) The point of the mixed weld metal is now on the line drawn under 3); starting from the point of the filler material of the degree of mixing is plotted (for example 20%, that is point in, 1 / 5 of the total length antragen); there is the point of the resulting structure.

Schaeffler diagram, Ni equivalent promotes austenite formation and chromium equivalent promotes ferrite formation

literature

  • Ulrich Dilthey: Welding Production Processes, Volume 2 . 3. Edition. Springer-Verlag, Berlin 2005, ISBN 3-540-21674-X .
  • Paul Gümpel: Stainless steels: basic knowledge, design and processing instructions , Expert Verlag, 2008, ISBN 3-816-92689-4 .

Web links

Schaeffler diagram calculator: [1] Calculator without welding filler: [2] Calculator for standard analysis: [3]

credentials

  1. ^ Anton L. Schaeffler: Constitution Diagram for Stainless Steel Weld Metal. In: Metal Progress. American Society for Metals, Cleveland, Ohio 1949: 56: 680-680B. ISSN  0026-0665
  2. ^ HJ Bargel, G. Schulze: Material Science . 12th edition. Springer Vieweg, 2018, ISBN 978-3-662-48628-3 , p. 277