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DMLS/SLM: Fatigue design rules
This page presents the S-N curves and fatigue limits of DMLS/SLM materials as determined during the experimental campaign of the A_MADAM project. This page also serves as the introductory page to present (“MS1 steel”, “PH1 steel” and “CX steel”) and future sections that describe fatigue performance of various materials used by DMLS/SLM technology, as well as to the sections that consider influences of production conditions (“Production conditions”) the post-processing (“Post-processing”) to the fatigue performance of products of DMLS/SLM technology.
Tables - notation and conventions
The fatigue design rules represent the most innovative, the largest and, probably, the most important part of the D4AM Wiki. Majority of the presented material is the result of the project A_MADAM, and its presentation will usually follow the methodology of that project.
The fatigue design rules describe the influence of material, production conditions and post-processing procedures to fatigue performance of DMLS/SLM products, and that complexity of relevant factors requires presentation of large numbers of S-N curves and fatigue limits for proper description of fatigue performance. The S-N curves and fatigue limits are determined using the standard ISO 1143 method.
A systematized access to the S-N curves and fatigue limits data is provided by tables that list the respective material, production conditions and post-processing procedure, which are listed in the headers of rows and columns of the table, like in the example below:
| Post processing procedure (steps in order) | Production (orientation and position) | |||||||
|---|---|---|---|---|---|---|---|---|
| 1st step | 2nd step | 3rd step | V | V up | V mid | V down | H | S |
| PP-1 | PP-2 | PP-3 | X | - | - | - | X | X |
In the actual tables, the signs “X” represent links to the D4AM Wiki pages with the S-N curves and fatigue limits obtained for samples manufactured under production conditions and post-processing procedures described by the headers of corresponding columns and rows of the table. The short explanation of the notation and conventions are given in the following tables, while the detailed explanations are given in the sections “Production conditions”, “Post-processing procedures” and “Materials” below.
| Production conditions | ||
|---|---|---|
| Code | Orientation of longitudinal axis | Position with respect to inert gas flow |
| H | horizontal | different |
| S | slanted (45°) | different |
| V | vertical | different |
| V up | vertical | upstream (inlet) |
| V mid | vertical | mid-stream (middle) |
| V down | vertical | downstream (outlet) |
| Post-processing steps | |
|---|---|
| Code | Explanation |
| S-P | shot-peening |
| H-T | heat treatment |
| M 0.5mm | machining that removed allowance of 0.5mm |
| M 1mm | machining that removed allowance of 1mm |
| M 2mm | machining that removed allowance of 2mm |
| M 3mm | machining that removed allowance of 3mm |
| M 4mm | machining that removed allowance of 4mm |
| no | step is not performed |
Production conditions
Production conditions, orientation of the longitudinal axis are described by the headers of the columns using the following codes:
- “H” for sets of samples manufactured with horizontal orientation of the longitudinal axis during building; the tested samples were manufactured in different positions with respect to inert gas flow;
- “S” for sets of samples manufactured so that their longitudinal axis was slanted (made an angle of 45° with horizontal) during building; the tested samples were manufactured in different positions with respect to inert gas flow;
- “V” for sets of samples manufactured with vertical orientation of the longitudinal axis during building; the tested samples were manufactured in different positions with respect to inert gas flow;
- “V up” for sets of samples manufactured with vertical orientation of the longitudinal axis during building and in positions close to the inlet of the inert gas stream;
- “V down” for sets of samples manufactured with vertical orientation of the longitudinal axis during building and in positions close to the outlet of the inert gas stream;
- “V mid” for sets of samples manufactured with vertical orientation of the longitudinal axis during building and in positions close to the middle of the inert gas stream;
Post-processing procedure
Post-processing procedure is presented by at most three steps described by the headers of the rows using the following codes:
- “S-P” for shot-peening procedure described in details at the page The influence of the position with respect to inert gas flow to fatigue performance of DMLS/SLM products.
- “H-T” for heat-treatment procedures described in details at the page The influence of heat treatment to fatigue performance of DMLS/SLM products
- “M 0.5 mm” for removal of a surface layer with thickness of 0.5 mm by machining
- “M 1 mm” for removal of a surface layer with thickness of 1 mm by machining
- “M 2 mm” for removal of a surface layer with thickness of 2 mm by machining
- “M 3 mm” for removal of a surface layer with thickness of 3 mm by machining
- “M 4 mm” for removal of a surface layer with thickness of 4 mm by machining
Material
The material of the samples is described by one whole row in table, and the description is relevant for the rows below the description of material. If all the samples described by a table are made from the same material, it is not described in the table, but in the title of the respective section.
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