首页|Microstructure analysis of martensite stainless steel by directed energy deposition and uniform high hardness
Microstructure analysis of martensite stainless steel by directed energy deposition and uniform high hardness
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NSTL
Elsevier
This investigation focuses on obtaining martensite stainless steel part with uniform mechanical properties along the building direction (BD) by plasma arc direct energy deposition (DED). A tailored 1Cr17Ni2B alloy powder and layer minimum temperature control process were employed. The results revealed that the tensile strengths along BD exhibited a good uniformity with a relative difference less than 1.4 % and the average ultimate tensile strength was 1382 MPa. The high microhardness along the BD also showed a good uniformity, only slightly fluctuated from 542-606 HV0.3 with a periodic length of one concave fish-scale pattern. Then the part along BD was simplified to overlapped concave fish-scale patterns. The microstructure evolution of fish-scale pattern was studied and the result showed that the concave fish-scale pattern was characterized by intragranular lath martensite and intergranular M-23(C,B)(6)+alpha-Fe eutectic structure. Besides, M-2(C,B) particles were distributed on intergranular alpha-Fe matrix. The layer minimum temperature control of 200 degrees C process was employed to ensure the eutectic M-23(C,B)(6) in a concave fish-scale pattern only partly dissolved during the deposition of the next one layer, not during the subsequent layers. It is helpful to deposite concave fish-scale patterns along the BD with similar volume fraction of eutectic M-23(C,B)(6) and mechanical properties. This investigation discloses a new method to deposite Fe-Cr-C-B alloy part containing intergranular carbides with uniform mechanical properties and high hardness along the BD.
Martensite stainless steelUniform propertiesEutectic carbidesIntrinsic heat treatment (IHT)Direct energy depositionCREVOLUTION
NSTL
Elsevier
