UCS-66 impact test

[maryam1979]

I have 2 questions about figure UCS-66.
1- for the thicknesses lower than 0.394in how can we use the diagrams?
2- for welded constructions which the thickness is over 4in is the impact test mandatory?

 

[metengr]

maryam1979;
Normally, I recommend posters to review the applicable section of the ASME Code, Section VIII, Div 1 UCS. I presume that you have done this, so I will attempt to answer your question;

1. Figure UCS is a diagram generated for impact exemption curves based on material thickness and minimum design metal temperature (MDMT). If your material of construction lies on or above the curve, impact testing is not required for the applicable minimum design metal temperature (MDMT) shown on the left axis. So, for example, material that would lie on Curve A, in Figure UCS-66, for thickness 0.394" or less, impact testing is not required for a minimum design metal temperature of 19 deg F or higher. As the thickness increases, the MDMT increases because of the effects of plane strain (or triaxial stresses).

2. It all depends on your selection of MDMT.

 

[JCrash]

2) for a governing thickness > 4" and a MDMT less than 120 F, yes, impact testing is required for the material. This can be found in UCS-66 (a) (1) towards the end.

 

[polani82342]

By UCS 66 b 3, impact testing for base material can be exempted or MDMT lowered, based ON Fig 66.1 to -155F.
If the base metal is exempt by this or the MDMT lowered by this, does same provision apply to weld procedures, HAZ and pRODUCTION WELDS SAME AS THAT FOR BASE METAL?

 

[eliebl]

See UCS 67 (d).

Also,
Material thinner than 0.10 can be used down to -55 w/o impact testing of material. UCS-66(d). Be careful if it requires a CRN. CSA B51 has overriding requirements.

EJL

 

[polani82342]

My question is whether the code exempts impact testing of weld procedures if the base material is exempt thru -155F by virtue of UCS66.1?

 

[polani82342]

UCS 66:
I think I have answered my own question. Weld PQRs and Production test plates need to be impact tested for MDMTs below -20F for curve C & D materials unless their weld rods are prequalified by impact testimg down to -55F. For MDMTs below -55F, no more exemptions and impact testing is mandatory for PQRs and Production Weld Test Plates.

Paul Polani