Sharpy test values of ASME materials 3

[Xianglu]

We are currently using normal carbon materials (not LT). However, there is an ISO V-test value requirement of not less than 27 J at a temperature of -15 deg C. Could anyone advise do the following ASME materials meet this requirement?
SA105
SA106 B
SA226 WCB
SA516 Gr 70
SA193 B7
Or do I have to use LT materials?
Thanks in advance.

 

[codeeng]

Not sure what SA226 WCB is. SA193-B7 is good down to -50F without impact testing. The other materials could be exempt depending on thickness, see UG-20(f) and UCS-66.

 

[Xianglu]

The equipment will be for European market, the EU Pressure Equipment Directive requires Sharpy value for all pressure vessel materials.

 

[metengr]

Are you sure about the SA 226 material, in lieu of SA 216? The A 226 is an ASTM Specification that was withdrawn in 1997 and was not replaced. This specification deals with electric resistance welded carbon steel boiler superheater tubes for high pressure service.

The other materials you listed should be able to meet the 27J at -15 deg C.

 

[Xianglu]

My typo. The SA226 should be SA216.
Thanks, Metengr

 

[SJones]

It's not a particularly onerous toughness requirement and materials from "acceptable" suppliers should readily meet the criterion (assume 27 J average; 21 J minimum individual) provided that the thicknesses you will use do not drop the test temperature further. Contact your "accepted" suppliers and see if they have toughness tested their materials for others and the results they achieved to get a feel if you are not confident. Also note that bolting has to achieve 40 J.

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdo/

 

[SJones]

It is assumed that EN 13445 is the applicable standard.

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdo/

 

[abbver98]

Xianglu and SJones,
The PED doesn't require explicitly an impact test ! It depends on code you apply and the material used. I'm in my 6 years and I supply equipment according to PED with application of ASME Code but without impact test. Of course Annex 7.5 requires an impact test but if you see in material section they speak about material properties (sufficient ductile). There is also a guidelines explaining this question.

 

[codeeng]

On the assumption that you can't use ASME exemptions and you must have impact testing then you should consider switching to LT material. Other than the plate, the material listed does not come with impact testing so you will need to special order this or do the additional testing on a stock item. This can be a problem with forgings and castings.

 

[DSB123]

abbver98,
The PED states under 4.0 Materials and in particular 4.1 a that "Materials for pressurised parts must have appropriate properties for all operating conditions which are reasonably foreseeable and for all test conditions, and in particular they should be sufficiently ductile and tough. Where appropriate, the characteristics of the materials MUST comply with the requirements of 7.5"

7.5 states "Unless other values are required in accordance with other criteria that must be taken into account, a steel is considered as sufficiently ductile to satisfy 4.1(a) if, ..... and its bending rupture energy measured on an ISO IV test-piece is no less than 27 J, at a temperature not greater than 20 Deg C but not higher than the lowest scheduled operating temperature."

With the above clauses in mind can you explain how without Testing a material can be considered as meeting this requirement?

 

[metengr]

The way I read the PED directive, I don't see why one could not justify use of ASME Boiler and Pressure Vessel Code impact test exemption curves for approved material as a way to justify not having to perform additional impact testing.

 

[Xianglu]

The Notified Body has informed that:
1. The ASME materials are acceptable by a particular material appraisal approach.
2. V-test and elongation values must meet PED requirement.
3. Manufacturer testing report shall be in accordance EN 10204.
4. Only those manufacturers who's Quality System Certificate is issued by an EU institute are recognized to be qualified to issue testing reports.

We have to prove that the material sharpy and elongation values meet PED limit. I want to know what is the sharpy value range for the common materials. Otherwise, I'll have to replace with LT materials, which have better sharpy performance.

 

[ggarciae]

Xianglu

May you tell us which is your NoBo and country?
It's more or less what ENAC (Spanish national acreditation and certification organitation) ask for to spanish NoBos.
A pair of precisions
4. Only those manufacturers who's Quality System Certificate is issued by an EU institute are recognized to be qualified to issue testing reports 3.1B (for main pressurized parts)
5. Otherwise manufacturers testing reports must be 3.1C or 3.2 for main pressurized parts


Regards from Barcelona
G. García

 

[Xianglu]

Thanks Barcelona,
We are a Canadian company supplying equipment to a French refinery.
Our NoBo is a North American institution with offices in the United States and Canada.

Regards,
Henry

 

[jamesl]

Henry,
Our Notified body told us the same things. Based on what I learned from a PED training course, I think they are right. PED does not accept ASME material automatically. Materials have to be approved indiviually by the Notified Body. Impact tests are mandatary.

BTW, the materials you listed should meet the impact value easily as long as they are not very thick.

 

[Xianglu]

Thanks Jim;
Do you have any impact value numbers for reference? My concern would be on the casting (>3" thick) and forging (>4" thick). Any suggestions?

 

[jamesl]

I am not a material guy. If you talk to a forging company, they probably will offer you Q&T instead of N&T. 27 J is easy to meet unless the test coupons need to go through long hours of simulated PWHT. Some E&C companies like to have the material tested for several cycles of PWHT.

I have no experience with casting. Last time one of our subcontractor used SA 217 and impact values were pretty
high.

 

[metengr]

Xianglu;
We seem to be mixing requirements for Charpy impact testing with material thickness. Does the PED specify Charpy impact testing with thickness limitations? If so, for your stated thickness ranges of > 3" for castings and >4" for forgings, I would highly recommend that you perform Charpy impact testing to meet the PED if you intend to use these materials. I still believe you can meet the 27J at -15 deg C even at midwall thickness testing for these materials because the heat treatments specified are such that thickness plays minimal role in the impact results. For the SA 216 WCB, you will need to have a quenched and tempered heat treatment.

Before I would switch to LT, run the Charpy impact tests, it might be a much cheaper option.

My 2 cents worth;
The effect of material thickness has more to do with fracture toughness behavior under a state of tri-axial stress at a pre-existing flaw or crack in a component. This is the rationale for the development of impact testing exemption curves for the ASME B&PV code, in lieu of using actual fracture toughness testing like KIc (which is the more reliable approach, but costs more and is time consuming) to address material thickness effects on fracture toughness behavior. Charpy V-notch impact testing simulates a state of tri-axial stress by using a sharp notch and high strain rates for testing. In reality, if you are worried about the effects of material thickness AND temperature on fracture toughness behavior, Charpy impact testing is NOT the best approach. If you are only interested in how material will respond at a certain temperature, regardless of material thickness, impact testing is quick and a cheaper cost alternative.

 

[weldtek]

metengr,
As always, you have provided valuable insight. Thanks.

 

[Xianglu]

Thanks, Metengr.
Your visions and suggestions are always valuable.
We will be performing some V-tests to validate the 27 J is achievable from the real mill production. My goal is nothing but to meet PED requirement and get CE certificate from the NoBo.