Forging Material SA-105 Vs SA-350 LF2
Agrawal Sunil (Mumbai -Stequ)
Dear Friends,
May I request you to guide me about the basic difference between two forging Material SA-105 Vs SA-350 LF2. Is it possible to use SA-105 below -29° C?
Best Regards,
Sunil Agrawal
EDTICB-Mumbai (STEQU)
Ph.: +91 22 6777
7237
Kannan....@linde-le.com
The subject is the ability to withstand the sustained stresses by the ductility and the grade of brittleness of the material from
ambient to lower temp. evaluated by the charpy test. There is no crystal change happening at lower temp. till -50.
The below points may clarify your question.
1) The composition difference is in the Carbon and Manganese composition inverse variation.
2) This effect makes the A350 better off than the A105 at lower temp. though the phys. property is same at lower temp.
3) The default heat treatment difference also helps A350 at lower temp. A350 requires min. Norm. or N&T or Q&T.
4) Not the least the class of LF2 is generally not specified. But it is makes an important diff. in the impact test requirement.
4) The ASME recommends the min. temp. as -50 for A350 LF2. A105 till -20.
Finally if the CE is same and Heat treatment is same and the Hardness being nearly equal and if it passes the charpy test
definitely A105 can be used below -20. However the welding may make the difference in why not using the A105 below -20 as
Manganese & Silicon makes an important difference in to use / not to use A105 at temp. lower than -20. But the latest manufacturing
processes can ensure the A105 manganese content at min.1.0%.
With regards,
Kannan.
| "Agrawal Sunil \(Mumbai
-Stequ\)" <S.Ag...@ticb.com>
Sent by: material...@googlegroups.com 27/08/2007 11:11
|
|
Bathula Raghuram (Mumbai - PIPING)
Q: basic difference between two forging Material SA-105 Vs SA-350 LF2?
The basic difference is its manufacturing (Melting) Process –
SA350: The steel shall be produced by any of the following primary processes: open-hearth, basic oxygen, electric-furnace, or vacuum-induction melting (VIM). The primary melting may incorporate separate degassing or refining, and may be followed by secondary melting using electroslag remelting (ESR), or vacuum-arc remelting (VAR).
The steel shall be fully killed, fine-grain practice. The molten steel may be vacuum treated prior to or during pouring of the ingot.
Where as SA105: there is no such requirement.
Also Heat treatment is another basic diff between these two N&T or Q&T will give an edge over SA105.
Q: Is it possible to use SA-105 below -29° C?
Yes provided the toughness results @ given design temp (MDMT) are meeting the construction code requirements
From: material...@googlegroups.com
[mailto:material...@googlegroups.com] On
Behalf Of Agrawal Sunil (Mumbai -Stequ)
Sent: Monday, August 27, 2007 2:41
PM
To:
material...@googlegroups.com
Cc: Wagh Nilesh (Mumbai - Stequ)
Subject: [MW:118] Forging Material
SA-105 Vs SA-350 LF2
Bathula Raghuram (Mumbai - PIPING)
“Susceptibility to brittle fracture of flanges in steel ASTM A105"
The attachment gives you the recommendations for pipe flanges made in forged steel complying with ASTM A 105, this research project was conducted by Belgian welding institute on a series of flanges.
The ASME code section VIII, division 1/ ASME B31.3 (with in the pressure temperature ratings of B16.5) permits the use of the steel grade ASTM A 105 up to a temperature of -29°C, without any provisions relating to the resistance to brittle fracture.
During an incident in 1999 in an HDPE (High Density Polyethylene) reactor a brittle fracture occurred at a temperature of -12°C in a 24’’ flange consisting of this grade of steel. .
The company where the incident took place ordered an investigation and different identical flanges made according to ASTM A 105 were subjected to a scrutiny of their
Material properties. This investigation showed that about 50% of the flanges had an analogue structure (microstructure and grain size) as the fractured flange and hence
Were equally liable to brittle fracture. In view of de ample use of this grade of steel in the (petro) chemical industry and the prevention of major accidents, the Administration of Labor Safety has initiated a research project in September 2000 to look deeper into the sensitivity to brittle fracture of ASTM A 105 grade steel. It resulted in June 2002 in a series of recommendations for new flanges as well as flanges already in service. This document includes all of these recommendations.
Enjoy reading the report and recommendations/conclusion at the end
Good luck
From: material...@googlegroups.com [mailto:material...@googlegroups.com] On Behalf Of Kannan....@Linde-LE.com
Sent: Monday, August 27, 2007 7:11
PM
To: material...@googlegroups.com
Subject: [MW:124] 120] Fw:
[MW:118] Forging Material SA-105 Vs SA-350 LF2
I have attached a metallographic original picture of a
sample tested recently of one major European supplier for reference. However it
is of a pipe material and not of forging. But it could be of good comparision.
The extreme fine grain is clearly visible which was obtained by Q&T process
of hot mill product and was statistically considered to be one of the best
supplier for LT pipe & thier HT process. The charpy value was 145 against
>=12J.
Also
the yield strength changes considerably in coarse-grained than fine-grained
steel during aging process. Also brittleness increases after the aging in
coarse-grained steel. So the heat treatment is the key complimented by the
managanese & silicon %. On the effect of manganese I will write in detail
tomorrow.