Carbide Precipitation during Processing of Two Low-Alloyed Martensitic Tool Steels with 0.11 and 0.17 V/Mo Ratios Studied by Neutron Scattering, Electron Microscopy and Atom Probe
Artikel i vetenskaplig tidskrift, 2022

Two industrially processed low-alloyed martensitic tool steel alloys with compositions Fe-0.3C-1.1Si-0.81Mn-1.5Cr-1.4Ni-1.1Mo-0.13V and Fe-0.3C-1.1Si-0.81Mn-1.4Cr-0.7Ni-0.8Mo-0.14V (wt.%) were characterized using small-angle neutron scattering (SANS), scanning electron microscopy (SEM), Scanning transmission electron microscopy (STEM), and atom probe tomography (APT). The combination of methods enables an understanding of the complex precipitation sequences that occur in these materials during the processing. Nb-rich primary carbides form at hot working, while Fe-rich auto-tempering carbides precipitate upon quenching, and cementite carbides grow during tempering when Mo-rich secondary carbides also nucleate and grow. The number density of Mo-rich carbides increases with tempering time, and after 24 h, it is two to three orders of magnitude higher than the Fe-rich carbides. A high number density of Mo-rich carbides is important to strengthen these low-alloyed tool steels through precipitation hardening. The results indicate that the Mo-rich secondary carbide precipitates are initially of MC character, whilst later they start to appear as M2C. This change of the secondary carbides is diffusion driven and is therefore mainly seen for longer tempering times at the higher tempering temperature of 600◦C.

STEM

APT

SANS

martensite

tool steel

carbides

tempering

precipitation

Författare

Erik Claesson

Swerim AB

Kungliga Tekniska Högskolan (KTH)

Hans Magnusson

Swerim AB

Joachim Kohlbrecher

Paul Scherrer Institut

Mattias Thuvander

Chalmers, Fysik, Mikrostrukturfysik

Fredrik Lindberg

Swerim AB

Magnus Andersson

Swerim AB

P. Hedstrom

Kungliga Tekniska Högskolan (KTH)

Metals

2075-4701 (eISSN)

Vol. 12 5 758

Ämneskategorier

Bearbetnings-, yt- och fogningsteknik

Metallurgi och metalliska material

Korrosionsteknik

DOI

10.3390/met12050758

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2022-05-31