Modellierung und Simulation des Warmumformverhaltens von hoch stickstofflegierten Stählen

High nitrogen steels (HNS) differ from conventional austenitic steels on their higher yield and tensile strength as well as improved high temperature strength. HNS show also a better corrosion resistance, pitting resistance and stress corrosion cracking resistance. However, these advantages are accompanied with some problems during hot deformation of HNS. Edges and surface cracks as well as forging cracks may appear. Time consuming and expensive finishing operations are required for these cracks which mean a serious drawback to economic processing of forging blocks. The aim of this thesis is the identification of a forging window for an economical production of HNS under consideration of the modeling of precipitation and the experimental simulation of deformation. The experiments were made on three HNS 1.4452, 1.4501, and 1.4882 and a reference steel 1.4301. On the modeling of precipitation, the phase diagrams were calculated with Thermo-Calc® software in order to determine precipitation characteristics and phase transformations. The investigation of precipitations helps to draw conclusions from appearing phases and dissolving temperatures. In order to simulate the deformation, the high temperature properties were determined at deformation temperatures between 900ºC and 1300ºC via hot tensile tests. The compression test defines also the effect of deformation temperature on the crack sensibility. As a result of experimental simulations, a forging window was determined. The results show the deformation temperature window is restricted for austenitic HNS 1.4452 and 1.4882 in compare to reference steel 1.4301 and super duplex HNS 1.4501.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2009

Author dc:creator

• Erisir, Ersoy

Contributors dc:contributor

• Bleck, Wolfgang

• info:eu-repo/classification/ddc/620
• Ausscheidung
• Schmieden
• Warmumformen
• Stickstoff
• Rissbildung
• Ingenieurwissenschaften
• hoch stickstofflegierte Stähle
• Warmumformbarkeit
• high nitrogen steels
• precipitation
• forging
• crack initiation
• hot formability

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-113207%22

OAI record oai:identifier

https://publications.rwth-aachen.de/oai2d?verb=GetRecord&metadataPrefix=oai_dc&identifier=oai%3Apublications.rwth-aachen.de%3A50672