Dear Harish,
I am sure you will find the details in ABS’s “Rules for Materials and Welding”, for the two ABS steels.
I don’t have these, but I have a rather similar document from DNV.
I will recommend you get the ABS document and try to check up there
In the DNV document I see that a grade E620 (is probably like your EQ63), shall have impact testing at -40 deg. C with minimum 41 J (for thicknesses 150 mm and less).
DNV grade E690 (is probably like your EQ 70), impact test at -40 deg. C with minimum 46 J.
ALFORM 500M has charpy requirements: test at -20 deg. C, energy: 40 J
The LeT N 20 I cannot say much about.
But everything looks very strange here. Some of these steels are QT-steels, some are TM steels. Charpy impact temperatures and energy are different between the different steels.
But please note: The steels you mention above are for structural purpose – not for pressure piping!
I think the best solution for you, Harish, is to hire a material expert for some days to try to sort it out.
You will need a real expert anyway to work with high strength QT steels, it is very tricky to qualify welding procedures for these steels.
regards
Kristian
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Harish Kannepalli
Sent: 25. juli 2011 17:57
To: materials-welding@googlegroups.com
Subject: Re: [MW:11916] CVN Energy
Dear Kristian,
I have PQRs running for piping as well as structures; welding code is AWS D1.1:2010; design conditions are -30°C; material is ABS EQ63/EQ70/ALFORM 500M/LeT N20.
2011/7/25 Kristian Lund Jepsen (KUJ) <KUJ@ramboll.com>
Dear Harish,
Don’t focus on the material you have – this is only a certificate for one heat number and shall demonstrate that your minimum requirement is fulfilled.
The problem is: What is the minimum requirement?
So please tell us:
a) Are we talking piping or steel structure?
b) What is the design code?
c) What are your design conditions?
d) What is the material standard for the mentioned material with MTC showing >300J CVN energy at -40°C?
Only then it will be possible to say something specific!
regards
Kristian
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Harish Kannepalli
Sent: 22. juli 2011 20:29
Subject: Re: [MW:11864] CVN Energy
Dear Kristian,
My doubt is still not cleared. I have a material with MTC showing >300J CVN energy at -40°C. Now my welding code is AWS D1.1, which states, " for materials with SMYS>640MPa, CVN energy shall be as per contractual requirements"; my contractor does not have any CVN acceptance criteria.
Now please tell me, how to get the acceptance criteria.
2011/7/19 Kristian Lund Jepsen (KUJ) <KUJ@ramboll.com>
Harish,
If your order (contract and/or design documentation) does not give any specific requirements regarding CVN, you are probably going to manufacture piping or steel in a low class, where there is no requirements on impact testing.
Then you don’t need any qualification of welding procedures as regards the impact energy.
But it might be a good idea to have that confirmed by your costumer.
regards
Kristian
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Harish Kannepalli
Sent: 18. juli 2011 19:27
Subject: Re: [MW:11814] CVN Energy
Thanks Kristian. Now i have an unlisted steel, whose base metal CVN energy in MTC shows 280J at -40°C; so what is acceptance for PQR coupon. Here we cannot consider base metal energy as acceptance criteria. I do not have contract/design requirements.
2011/7/18 Kristian Lund Jepsen (KUJ) <KUJ@ramboll.com>
The 27 J impact energy (minimum) at the minimum design temperature did arrive from European regulations and standards as mentioned below. They are based on experience on what is “safe”.
The 27 J will apply both to base material (pipe, beam, plate, etc.) and welds (basically the HAZ of the welds). The welding procedure (the welding procedure shall be qualified including impact testing, the test will be part of the PQR.
The welds are often the most critical ones in relation to charpy. Going back in the history, it was also the welds (HAZ) that failed on the Liberty ships being built during world war II. This was really the beginning of requiring charpy tests in connection with qualification of welding procedures. Ref. for example: http://en.wikipedia.org/wiki/Liberty_ship
regards
Kristian
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Harish Kannepalli
Sent: 17. juli 2011 19:19
Subject: Re: [MW:11791] CVN Energy
Dear All,
I think i could not convey my concern properly. How did the value 27J arrive? For base materials, we can say minimum requirements, but design codes also ask for min. energy requirements on weld coupons; where the microstructures are different from that of base materials.
2011/7/17 Kristian Lund Jepsen (KUJ) <KUJ@ramboll.com>
Yes, depends on, if you think about piping or steel structure – and also the code you are using.
In Europe, all piping under PED (Pressure Equipment Directive, 97/23/EC) shall as a minimum have impact energy 27 J at the minimum design temperature of the piping. This is also implemented in the European piping code, EN 13480 and the European pressure vessel code, EN 13445.
For structural steel in accordance with Eurocode 3 (EN 1993), the basic requirement is stated in EN 1993-1-10. Typically it will be required to verify 27 J at min. design temperature, but the actual test temperature/energy is depending on the thickness of the material. A table in EN 1993-1-10 states for EN 10025 steels the actual conditions (temperature and energy) and to what temperatures they may be used, depending on the thickness of the steel plate or section/profile.
regards
Kristian
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of sudhakar kuppuswamy
Sent: 16. juli 2011 20:04
To: materials-welding@googlegroups.com
Cc: pgoswami@quickclic.net
Subject: Re: [MW:11771] CVN Energy
Dear Harish,
Based on the international code 7standard, for a particular standards material there will be a value of energy to be absorbed and temperature at which the CVN test has to be done. refer the tables given in the required codes ,in case of ASME materials refer SEC 2 PART A and B for base material and PART C for welding consumables. You will get any idea.
Since impact properties of a material depends on chemical composition and final Heat treatment carried out during manufacturing, from my knowledge I don’t think there will be any specific formula to correlate . Generally CVN test is carried out on trial and error basis in manufactures industries .
On Sat, Jul 16, 2011 at 10:18 PM, Harish Kannepalli <harishkannepalli@gmail.com> wrote:
Dear Sir,
I have a very basic doubt since long time, posted in this forum also. How do we get the minimum energy requirements for CVN tests at a particular temperature? Is there any mathematical calculation to get this energy?
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regards,
Harish.
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regards,
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regards,
Harish.
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regards,
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