Tensile test acceptance criteria - Unassigned Metals in ASME

By 619822 Date 09-21-2019 12:25

I have a condition were I tested SB AL 5052 H32 Material which is unassigned as per ASME Sec IX 2017. The UTS of the Grade as per ASTM B 209M is 215 Mpa, when I did the Tensile test after welding for PQR qualification, The Sample was broken on the Parent Metal and the UTS reading Showed 190 Mpa.

In ASME SEC IX QW 422 SB 209 Grade 5052 is specified and the Min Tensile given is 170 MPa

in case of Unassigned metals,QW 424.1 states that "The minimum tensile strength shall be defined by the organization that specified the unassigned metal if the tensile strength of that metal is not defined by the material specification."

But as per QW 153.1 (a) the minimum specified tensile strength of the base metal is the acceptance criteria for the tensile test .

can I consider this a PASS since it Failed at the parent metal irrespective of the tensile value obtained in the test??..

By 803056

Date 09-21-2019 15:00

The codes recognize that the mechanical properties of many aluminum alloys are different in the "wrought" condition and in the "as welded" condition. The properties published by ASTM (or others) and other base metal specifications list the properties in the "as wrought" condition. In the case of aluminum alloys, they can be strengthened by either heat treatment or stain hardening as indicated by either the T number or H number. Once these alloys are welded, the strength of the HAZ are typically weakened such that the values published by ASTM are no longer relevant from a testing standpoint or for the purpose of design. In some cases, the yield strength can be reduced by nearly 50% and tensile strength reduced by 40%.

Section IX does not list the mechanical properties for the as wrought materials, instead it lists the minimum tensile strength of the material after welding. So, in your case 5052 alloy is listed with a minimum tensile strength of 25 ksi or 170 MPa. I would accept the welded sample if it failed at 190 MPa.

Al