These are AISI designations and the chemistry requirements are quite commonly published. Briefly the first two numbers indicate the alloy type and the last two numbers indicate the nominal carbon content. Thus for the figure shown you have carbon steel (1040) hardness vs. various alloy steels hardness all with the same nominal carbon content (~0.40%). The figure also shows that alloying content will affect the depth of hardening as demonstrated in the Jominy test. At the maximum cooling rate, at the quenched end of the Jominy specimen, the hardnesses are nearly the same for all the steels because martensite is formed almost exclusively. This is as expected, since the hardness of martensite is solely dependent on carbon content and all the steels have the same carbon content. As the cooling rate decreases (increasing distance from the quenched end of the specimen, i.e. DQE) the formation of martensite is dependent on the alloy content, thus you see a rapid fall off in the carbon steel hardness (1040) (no deliberate alloying elements) as opposed to alloy steels. The figure shows that various alloying schemes increase hardenablility more than others and is shown in the figure as higher hardness with distance from the quenched end.
You may find additional and more complete discussion of hardenability and the Jominy test in any basic metallurgy/materials textbook or a beginning book on heat treatment of steels.
John
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of limesh M
Sent: Thursday, June 10, 2010 2:20 AM
To: materials-welding@googlegroups.com
Subject: Re: [MW:5511] RE: 5478] RE: 5437] Hardness of Untempered Martensite
Dear all,
What is meant for 4340,4140,8640,5140 and 1040 on the graph.It will be highly helpful if any one explain the graph in detail.Hope someone will take initiative.
Thanks and Regards
On Thu, Jun 10, 2010 at 9:36 AM, Warke, Robert <RobertWarke@letu.edu> wrote:
You’re welcome, Mr. Babu. The previous figure does apply to alloy steels as well as to plain-carbon.
Alloy content in a ferritic steel strongly influences its hardenability, which is how easily martensite can be produced by quenching its austenite. Carbon content, on the other hand, determines the hardness of any martensite that is produced, and thus determines the maximum attainable hardness of a steel. The attached figure demonstrates both of these principles.
~RWW
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Kathalingam Babu
Sent: Wednesday, June 09, 2010 7:53 PM
Subject: Re: [MW:5504] RE: 5478] RE: 5437] Hardness of Untempered Martensite
Mr.Robert,
Thanks,
Will this figure applicable to alloy steels ?
I assume that, it will applicable to plain carbon steels only.
Regards,
K.Babu
Singapore
----- Original Message -----
From: Warke, Robert
Sent: Wednesday, June 09, 2010 8:29 PM
Subject: [MW:5492] RE: 5478] RE: 5437] Hardness of Untempered Martensite
Mr. Babu,
The hardness of untempered martensite is determined almost entirely by its carbon content, as shown in the attached diagram.
Regards,
R. W. Warke
Robert W. Warke, P.E.
Associate Professor of
Welding & Materials Joining
School of Engineering & Engineering TechnologyLeTourneau University
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Kathalingam Babu
Sent: Tuesday, June 08, 2010 6:21 AM
To: materials-welding@googlegroups.com
Subject: [MW:5437] Hardness of Untempered Martensite
Hi
Any body have the idea on hardness for the untempered Martensite ?
What will be the morphology of micro?
Thanks & Regards,
K.Babu
Singapore--
To post to this group, send email to materials-welding@googlegroups.com
To unsubscribe from this group, send email to materials-welding-unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
--
To post to this group, send email to materials-welding@googlegroups.com
To unsubscribe from this group, send email to materials-welding-unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
--
To post to this group, send email to materials-welding@googlegroups.com
To unsubscribe from this group, send email to materials-welding-unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
--
To post to this group, send email to materials-welding@googlegroups.com
To unsubscribe from this group, send email to materials-welding-unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
No comments:
Post a Comment