ISSN 2594-5297
60th Seminar on Rolling, Metal Forming and Products — Vol. 60, Num. 60 (2025)
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Abstract
The austenitic valve steel WNr. 1.4882 (X50CrMnNiNbN21-9) is highly alloyed with Cr, Mn, Ni with significant additions of Nb, W, C and N, so it presents a narrow hot rolling range temperature and is susceptible to cracking during the process. This paper describes part of a study developed to evaluate the effect of different temperatures and deformation levels on hot formability of this specialty alloy. The hot rolling was done using wedges with geometries and effective deformation levels defined by thermomechanical simulation in DEFORM 3D®. The research material was processed in a pilot-scale rolling mill and the microstructures were analyzed via optical microscopy and SEM/EDS. The results showed that wedge rolled at 1230°C (heating temperature of 1260°C) exceeded the solidus temperature in the region subjected to the highest deformation and due to this phenomenon, it presented grain boundaries decohesion that generated cracks. Therefore, temperatures higher than 1230°C should be avoided during forming.
THE AUSTENITIC VALVE STEEL WNR. 1.4882 (X50CRMNNINBN21-9) IS HIGHLY ALLOYED WITH CR, MN, NI WITH SIGNIFICANT ADDITIONS OF NB, W, C AND N, SO IT PRESENTS A NARROW HOT ROLLING RANGE TEMPERATURE AND IS SUSCEPTIBLE TO CRACKING DURING THE PROCESS. THIS PAPER DESCRIBES PART OF A STUDY DEVELOPED TO EVALUATE THE EFFECT OF DIFFERENT TEMPERATURES AND DEFORMATION LEVELS ON HOT FORMABILITY OF THIS SPECIALTY ALLOY. THE HOT ROLLING WAS DONE USING WEDGES WITH GEOMETRIES AND EFFECTIVE DEFORMATION LEVELS DEFINED BY THERMOMECHANICAL SIMULATION IN DEFORM 3D®. THE RESEARCH MATERIAL WAS PROCESSED IN A PILOT-SCALE ROLLING MILL AND THE MICROSTRUCTURES WERE ANALYZED VIA OPTICAL MICROSCOPY AND SEM/EDS. THE RESULTS SHOWED THAT WEDGE ROLLED AT 1230°C (HEATING TEMPERATURE OF 1260°C) EXCEEDED THE SOLIDUS TEMPERATURE IN THE REGION SUBJECTED TO THE HIGHEST DEFORMATION AND DUE TO THIS PHENOMENON, IT PRESENTED GRAIN BOUNDARIES DECOHESION THAT GENERATED CRACKS. THEREFORE, TEMPERATURES HIGHER THAN 1230°C SHOULD BE AVOIDED DURING FORMING.
Keywords
High nitrogen steel, Hot rolling, X50CrMnNiNbN21-9, WNr. 1.4882
High nitrogen steel, Hot rolling, X50CrMnNiNbN21-9, WNr. 1.4882
How to cite
Fernandes, Thaís Melo; Farina, Alexandre Bellegard; Coury, Francisco Gil; Mazzer, Eric Marchezini.
EFFECT OF TEMPERATURE AND DEFORMATION ON HOT FORMABILITY OF HIGH NITROGEN VALVE STEEL WNR. 1.4882 (VV50HCN)®,
p. 272-281.
In: 60th Seminar on Rolling, Metal Forming and Products,
São Paulo, Brasil,
2025.
ISSN: 2594-5297, DOI 10.5151/2594-5297-42156
