Back to Low Alloy Medium Carbon QT
ML00129 - Apr.2018

Non qualified WPS for High Strength Steel

Micrography of the weld metal at the face of the joint showing the acicular ferrite structure with some regions where the grains started recristalization.

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of the at the face of the joint showing the with some regions where the grains started recristalization.
M

Material

Low Alloy Medium Carbon QT
  • UNS G86300
  • AISI 8630
  • AWS A 5.28 ER 80S-D2
  • AWS A 5.5 E 10018-D2
Ds

Description

A coupon of a high strength (YS > 517MPa), tubular, was welded by a - (root) and (fill, cap and temper bead); to be quailified according to IX and NACE 15156, but it failed because the presented ultimate strength lower than the minimum requirement for the . The metallurgical analysis evidenced degradation of the in the due to a long cycle at a temperature higher than the recommended for the .

C

Chemistry (% in weight)

Base Metal

0.30C; 0.22Si; 0.78Mn; 0.007P; 0.002S; 0.97Cr; 0.83Ni; 0.37Mo; 0.17Cu; 0.005V.

Weld metal - face

0.22C; 0.33Si; 1.88Mn; 0.014P; 0.012S; 0.11Cr; 0.74Ni; 0.24Mo; 0.03Cu; 0.008V.

Weld metal - root

0.22C; 0.32Si; 1.24Mn; 0.011P; 0.01S; 0.31Cr; 0.35Ni; 0.24Mo; 0.21Cu.

Associated Images
Micrographic detail of the weld metal with islands of a coarse ferritic structure, degradated (recristalized) from an acicular morphology during to the long heat treatment cycle in high temperature. The post welding heat treatment (PWHT) was conducted during 12 hours at 640°C.
700
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Coarse Structure
Micrography of the weld metal, at the face, presenting regions of large ferritic grains. The acicular ferrite structure in the columnar (previous austenitic) grains has suffered degradation due to the long heat treatment cycle (12 hours) in high temperature.
96
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Weld Metal
Micrography of the weld metal, at the face, presenting regions of large ferritic grains. The acicular ferrite has suffered degradation due to the long heat treatment cycle (12 hours) in a temperature of 640°C, that is higher than the recommended for the D2 filler metal.
78
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Weld Metal
Macrography of the welded joint taken from the vertical up part of the joint, presenting the root in one pass, the fill of the joint in three passes, the cap in three passes and two temper bead passes. The 10" diameter tube, 9.5mm thick, was welded by GTAW in the root (80SD2 filler metal) and by SMAW for fill, cap and temper bead passes (10018-D2 filler metal).
77
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - NItal Etched MacroDf - Welded Joint
WPS welded in 6G qualification welding position and tested according to ASME IX and NACE ISO 15156. Minimum preheating of 250°C. Two temper bead passes. PWHT at 640°C during 12 hours. Tube diameter 10". Thickness 3/8". V groove 70°. Root opening 1/8". NOT APPROVED due to ULTIMATE STRENGHT lower than the base metal minimum requirements.
87
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - WPS summaryDf - Welded Joint
Aspect of the internal surface of the tube, presenting the aspect of the root, after welding and heat treatment.
63
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Aspect Before AnalysisDf - Internal Surface
Aspect of the external surface of the tube, presenting the aspect of the cap and temper bead passes, after welding and heat treatment.
54
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Aspect Before AnalysisDf - External Surface
Micrography of the base metal, in low magnification, showing regions of segregations in a quenched and tempered martensitic structure.
52
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Base Metal
Micrography of the base metal showing a quenched and tempered martensitic structure. The base metal adopted in the test coupon presented a hardness level of 217HB (Brinell hardness of the certificate) and after the PWHT cycle the measured base metal hardness is 224 HV10.
59
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Base Metal
Micrographic detail of the base metal structure, quenched and tempered martensite. The base metal adopted in the test coupon presented a hardness level of 217HB (Brinell hardness of the certificate) and after the PWHT cycle the measured base metal hardness is 224 HV10.
51
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Martensite
Micrography of the heat affected zone at the face of the joint. It is possible to see that even close to the fusion line the material was reheated in high temperature, suggesting that the temper bead was effective.
53
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Heat Affected Zone
Micrography of the heat affected zone at the face of the joint, close to the fusion line. The hardness level at the HAZ was 248 HV10.
58
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Heat Affected Zone
Micrographic detail of the heat affected zone at the face of the joint, close to the fusion line. The structure is martensitic but the previous austenite grain boundary was not large. 248HV10.
47
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Martensite
Micrography of the weld metal at the face of the joint. It is possible to see the columnar grains of acicular ferritic structure. The hardness level of this region varied a little. From 231HV10 at the root until 250HV10 close to the face.
50
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Weld Metal
Micrography of the weld metal at the face of the joint showing the acicular ferrite structure with some regions where the grains started recristalization.
48
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Weld Metal
Micrographic detail of the weld metal at the face of the joint showing the acicular ferrite structure. The hardness level in this region is about 250HV10.
41
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Acicular Ferrite
Micrography of the heat affected zone at the root of the joint, submitted to several welding reheating cycles.
36
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Heat Affected Zone
Micrography of the heat affected zone at the root of the joint, submitted to several welding reheating cycles. The structure is still martensitic but presented a refined previous austenite structure.
30
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Heat Affected Zone
Micrographic detail of the heat affected zone at the root of the joint, submitted to several welding reheating cycles. The structure is martensitic with a refined previous austenite structure.
38
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Martensite
Micrography of the weld metal at the root of the joint. It is possible to see only reheated regions of primary ferritic structure. The average hardness level of this region is 231HV10.
34
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Weld Metal
Micrography of the weld metal at the root of the joint showing the equiaxial ferritic structure.
33
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Weld Metal
Micrographic detail of the weld metal at the root of the joint showing a mixture of acicular structure with equiaxial ferritic structure. The hardness level in this region is about 231HV10.
34
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Ferrite