Change search
ReferencesLink to record
Permanent link

Direct link
Control of weldability: Research leading to the development of two new quenched and tempered tool steels
KTH, Superseded Departments, Production Engineering.
2004 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

The understanding of the hardenability is important in steel development with respect to weldability of steels as well as to the design of quenched and tempered steels.The common way to judge if steel is suitability to welding is the use of a carbon equivalent, which reflects the alloy content to the hardenability of the heat affected zone (HAZ). Most common of these equivalent is the IIW carbon equivalent wich has been in use for decades.

However, this is an empirical equivalent, developed for CMn steels, and it doesn't say anything about the mechanical properties obtained in the HAZ. As a guideline a maximum HAZ hardness of 350 HV is normally put to avoid cold cracking in the HAZ. Numerous carbon equivalents have been published during the years, but few have been accepted and used. A drawnback of all these equivalents is that they have been evaluated for a set of chemical compositions which may be quite narrow, or that they have been evaluated on steels produced having other cleanliness, residual element levels etc. as is common in modern steelmarketing.

The hardenability of steel designated to quenching and tempering is normally evaluated using either Jominy testing or using a calculation using the Grossmann formalism. As the hardenability described in the carbon equivalents used in welding and the hardenability of quenched and tempered steels using the Grossmann formalism are two different descriptions of the same phenomenon the aim of this thesis is to link these two formalisms together and use the knowledge from the HAZ hardenability to design quenched and tempered steels. The goal is to produce such steel grades having a much better weldability as compared with standard grades available at the market.

In this work the hardenability in the heat affected zone (HAZ) in weldments in high strength low alloyed steels (HSLA steels) having a yield strength of 350 MPa. This part microalloying elements on the phase transformations which take place during cooling from the peak temperature of the welding cycle. These results have been linked to the mechanical properties of the HAZs.

In the second part of this thesis the development of tool steel grades with respect to optimise both hardenability with respect to;

- matrix hardenability (i.e the Grossmann approach)

- an enhanced weldability of such new steels due to a lower alloying content than is usual in such grades

Place, publisher, year, edition, pages
Stockholm: Industriell produktion , 2004. , 47 p.
Trita-IIP, ISSN 1650-1888 ; 04:12
Keyword [en]
Materials science
Keyword [sv]
National Category
Materials Engineering
URN: urn:nbn:se:kth:diva-70OAI: diva2:14682
Public defence
2004-12-08, sal M2, Brinellvägen 64, Stockholm, 10:00
Available from: 2004-12-08 Created: 2004-12-08 Last updated: 2012-03-20

Open Access in DiVA

fulltext(512 kB)5344 downloads
File information
File name FULLTEXT01.pdfFile size 512 kBChecksum MD5
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Hansson, Per
By organisation
Production Engineering
Materials Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 5344 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 1192 hits
ReferencesLink to record
Permanent link

Direct link