Effect of silicon on CGHAZ toughness and microstructure of microalloyed steels

Journal Article · Wed Feb 01 04:00:00 EST 1995 · Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States)

DOI:https://doi.org/10.1007/BF02664681· OSTI ID:6874778

Taillard, R; Foct, J ^[1]; Verrier, P; Maurickx, T ^[2]

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1. Univ. of Lille, Villeneuve d'Ascq (France). Physical Metallurgy Lab.
2. Sollac, Dunkerque (France). Centre de Recherches et de Developpement Metallurgiques

The increasingly severe environment of offshore petroleum sites has spurred metallurgists to improve structural steels. In order to be used, the steels must satisfy stringent requirements for the base metal and, particularly, in the weldments. Cold cracking and low toughness levels are two major problems induced by welding operations. The aim of this article is to present the beneficial effect of a reduction of silicon content on coarse-grained heat-affected zone (CGHAZ) toughness. This study was achieved with experimental and industrial E355 structural steels. These 0.09 wt pct C steels were Ti-microalloyed with silicon contents ranging from 0.05 to 0.5 wt pct. First, the authors demonstrate that the CGHAZ toughness is predominantly affected by the volume fraction of retained austenite ([gamma]r). Second, the authors show that the existence of retained austenite pertains only to its carbon enrichment. This enrichment is promoted essentially by an increase of the silicon level due to the retarding action of silicon on the formation of carbides in ferrite as well as in austenite. In the same way, the increase of silicon content slows down the decomposition of retained austenite into pearlite. The reduction of the silicon content of the steel greatly increases the ductility of the CGHAZ through the decrease of the volume fraction of retained austenite.

• OSTI ID: 6874778
• Journal Information: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States), Journal Name: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States) Vol. 26:2; ISSN 0360-2133; ISSN MTTABN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
360103 -- Metals & Alloys-- Mechanical Properties
ALLOYS
DATA
ELEMENTS
EXPERIMENTAL DATA
FRACTURE PROPERTIES
HEAT AFFECTED ZONE
INFORMATION
IRON ALLOYS
IRON BASE ALLOYS
LOW ALLOY STEELS
MECHANICAL PROPERTIES
METALLURGICAL EFFECTS
MICROSTRUCTURE
NUMERICAL DATA
OFFSHORE PLATFORMS
OIL WELLS
SEMIMETALS
SILICON
STEELS
WELLS
ZONES