Regarding Impact testing of Duplex SS Material
Regarding Impact testing of Duplex SS Material
(OP)
I have a query regarding Impact Testing of Duplex SS Material.
As per ASME Section VIII Div. 1, Clause UHA-51(d)(3) Impact testing is exempted for Duplex SS as follows:
for the following steels in all product forms at MDMTs of −20°F (−29°C) and warmer:
(a) austenitic ferritic duplex steels with a nominal material thickness of 3⁄8 in. (10 mm) and thinner;
Does than mean,
1. Duplex SS having MDMT less than -29°C requires irrespective of thickness?
2. Duplex SS having (any) MDMT warmer than -29°C requires Impact testing irrespective of Thickness? Suppose take an example of MDMT 25°C. Will it call Impact Testing for any thickness?
As per ASME Section VIII Div. 1, Clause UHA-51(d)(3) Impact testing is exempted for Duplex SS as follows:
for the following steels in all product forms at MDMTs of −20°F (−29°C) and warmer:
(a) austenitic ferritic duplex steels with a nominal material thickness of 3⁄8 in. (10 mm) and thinner;
Does than mean,
1. Duplex SS having MDMT less than -29°C requires irrespective of thickness?
2. Duplex SS having (any) MDMT warmer than -29°C requires Impact testing irrespective of Thickness? Suppose take an example of MDMT 25°C. Will it call Impact Testing for any thickness?





RE: Regarding Impact testing of Duplex SS Material
1. Duplex SS having MDMT less than -29°C requires irrespective of thickness?
- Yes.
2. Duplex SS having (any) MDMT warmer than -29°C requires Impact testing irrespective of Thickness? Suppose take an example of MDMT 25°C. Will it call Impact Testing for any thickness?
- No. Impact testing for MDMT > -29°C is only required for materials having a thickness greater than 10 mm.
RE: Regarding Impact testing of Duplex SS Material
2) No, thickness 3/8" and less can be exempted
For your exmaple, see 2) above.
Regards,
Mike
RE: Regarding Impact testing of Duplex SS Material
Sorry. I think some typographical error in my question 2.
I will reform my question 2. as follows:
2. Duplex SS having MDMT warmer than -29°C requires Impact testing (for thickness more than 10 mm) irrespective of MDMT?
Suppose my MDMT is 25°C or say 300°C. Will in that case aslo Duplex SS have to be Impact Tested?
RE: Regarding Impact testing of Duplex SS Material
I will say an MDMT of 300 C would be unusual :)
Regards,
Mike
RE: Regarding Impact testing of Duplex SS Material
Yes. I also agree.:)
I just put that as an example.
Was really surprised that Austenitic SS can be exempted from Impact Testing for MDMTs warmer than -198°C.
Wheras Duplex SS (Austenitic & Ferritic) have to be impact Tested irrespective of MDMT if thickness exceeds 10 mm.
Thanks anyway.
Have a Nice Day!
RE: Regarding Impact testing of Duplex SS Material
Regards,
Mike
RE: Regarding Impact testing of Duplex SS Material
RE: Regarding Impact testing of Duplex SS Material
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RE: Regarding Impact testing of Duplex SS Material
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RE: Regarding Impact testing of Duplex SS Material
RE: Regarding Impact testing of Duplex SS Material
A description of the grades to be welded would have been more meaningful.What's the duplex grade to be welded, Duplex-31803/32205 or super duplex UNS-32750/32760.
The ASME Section VIII requirements for impact testing for DSS base and weld metals are given in UHA-51(d)(3). They require impact testing of all DSS thicker than 10 mm (3/8 in.) or those with an MDMT less than –29 °C (–20 °F).
For a design temperature above -29Deg C, strictly ASME Sec-VIII, DIV-1 does not require impact test. However if the design specifications of any of the oil and gas majors are applicable impact test is mandatory (say like Shell-EP 61.40.20.31). For duplex/ and super duplex (especialliy super duplex) impact test is one way of determining the sensitivity of the steel to imtermetallic formation. See ASTM A923, method B for guidence.
Thanks.
Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
Ontario, Canada.
ca.linkedin.com/pub/pradip-goswami/5/985/299