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ML00053 - Mar.2017

SAW Longitudinal Seam of X70 Pipe

The micrography of the pipe in the longitudinal section shows an aligned structure.

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The of the in the shows an aligned .
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Material

Microalloyed Steel
  • API 5L grade X70
Ds

Description

This X70 UOE , longitudinally welded by , was adopted for use in conditions. It presents a refined -bainitic-perlitic and was welded in two passes, the first from inside and the last from outside of the pipe. The also presents a refined structure.

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Chemistry (% in weight)

Pipe Analysis

0.10C; 0.20Si; 1.69Mn; 0.020P; 0.006S; 0.07Nb; 0.04V; 0.02Cr; 0.01Ni; 0.01Mo; 0.01Cu.

Weld Metal Analysis

0.09C; 0.31Si; 1.62Mn; 0.022P; 0.012S; 0.04Cr; 0.02Ni; 0.17Mo; 0.05Cu; 0.02V.

Associated Images
Macrosection transverse to the longitudinal seam weld, presenting the two passes, the first welded from the internal side and the second welded from the external side. It is possible to see the columnar grains of the weld and the heat affected zone (HAZ) from each pass. See the schematic drawing in the next figure
427
VIEW
ML00053 / Mar.2017
SAW Longitudinal Seam of X70 Pipe
M - Microalloyed SteelP - Longitudinal Seam Welded PipeAp - SubseaCd - Welding
Cm - NItal Etched MacroDf - Welded Joint
Schematic drawing presenting the two passes, the first welded from the internal side and the second welded from the external side.
75
VIEW
ML00053 / Mar.2017
SAW Longitudinal Seam of X70 Pipe
M - Microalloyed SteelP - Longitudinal Seam Welded PipeAp - SubseaCd - Welding
Cm - Identification drawingDf - Welded Joint
The micrography of the pipe in the longitudinal section shows an aligned structure.
60
VIEW
ML00053 / Mar.2017
SAW Longitudinal Seam of X70 Pipe
M - Microalloyed SteelP - Longitudinal Seam Welded PipeAp - SubseaCd - Welding
Cm - Nital Etched Micrography by OMDf - Base Metal
Detail of the microstructure in the center of the plate, in the longitudinal section. The structure is refined and presents different ferritic grain sizes.
49
VIEW
ML00053 / Mar.2017
SAW Longitudinal Seam of X70 Pipe
M - Microalloyed SteelP - Longitudinal Seam Welded PipeAp - SubseaCd - Welding
Cm - Nital Etched Micrography by OMDf - Base Metal
Detail of the microstructure in the center of the plate, in the longitudinal section. The ferritic structure is refined and presents different grain sizes. Carbides are presented in different morphologies (perlite, precipitated) and there are probably microphases (aligned in a central segregation line).
55
VIEW
ML00053 / Mar.2017
SAW Longitudinal Seam of X70 Pipe
M - Microalloyed SteelP - Longitudinal Seam Welded PipeAp - SubseaCd - Welding
Cm - Nital Etched Micrography by OMDf - Base Metal
Micrography of the fusion line of the second pass (not reheated). The HAZ is bainitic and the weld metal presents columnar grains (of the previous austenite).
60
VIEW
ML00053 / Mar.2017
SAW Longitudinal Seam of X70 Pipe
M - Microalloyed SteelP - Longitudinal Seam Welded PipeAp - SubseaCd - Welding
Cm - NItal Etched MacroDf - Fusion Line
Micrographic detail of the fusion line of the second pass (not reheated). The HAZ is bainitic and the weld metal microstructure is predominantly formed by acicular ferrite.
51
VIEW
ML00053 / Mar.2017
SAW Longitudinal Seam of X70 Pipe
M - Microalloyed SteelP - Longitudinal Seam Welded PipeAp - SubseaCd - Welding
Cm - Nital Etched Micrography by OMDf - Fusion Line
Center of the weld in the second pass. Columnar grains of the previous austenite.
44
VIEW
ML00053 / Mar.2017
SAW Longitudinal Seam of X70 Pipe
M - Microalloyed SteelP - Longitudinal Seam Welded PipeAp - SubseaCd - Welding
Cm - Nital Etched Micrography by OMDf - Weld Metal
Fusion line of the first pass (reheated in high temperature). The HAZ is bainitic and the weld metal microstructure is predominantly formed by acicular ferrite.
43
VIEW
ML00053 / Mar.2017
SAW Longitudinal Seam of X70 Pipe
M - Microalloyed SteelP - Longitudinal Seam Welded PipeAp - SubseaCd - Welding
Cm - Nital Etched Micrography by OMDf - Fusion Line
Micrographic detail of the fusion line of the first pass (reheated in high temperature). The HAZ is bainitic and the weld metal microstructure is predominantly formed by acicular ferrite.
37
VIEW
ML00053 / Mar.2017
SAW Longitudinal Seam of X70 Pipe
M - Microalloyed SteelP - Longitudinal Seam Welded PipeAp - SubseaCd - Welding
Cm - Nital Etched Micrography by OMDf - Fusion Line
Micrographic detail of the fusion line of the first pass (reheated in high temperature). The HAZ is bainitic and the weld metal microstructure is predominantly formed by acicular ferrite.
38
VIEW
ML00053 / Mar.2017
SAW Longitudinal Seam of X70 Pipe
M - Microalloyed SteelP - Longitudinal Seam Welded PipeAp - SubseaCd - Welding
Cm - Nital Etched Micrography by OMDf - Fusion Line
Micrographic detail of the fusion line of the second pass (not reheated). Bainitic HAZ and acicular ferrite in the weld metal.
45
VIEW
ML00053 / Mar.2017
SAW Longitudinal Seam of X70 Pipe
M - Microalloyed SteelP - Longitudinal Seam Welded PipeAp - SubseaCd - Welding
Cm - Nital Etched Micrography by OMDf - Fusion Line
Micrographic detail of the center of the weld in the second pass (not reheated). Fine structure mainly formed by acicular ferrite.
31
VIEW
ML00053 / Mar.2017
SAW Longitudinal Seam of X70 Pipe
M - Microalloyed SteelP - Longitudinal Seam Welded PipeAp - SubseaCd - Welding
Cm - Nital Etched Micrography by OMDf - Weld Metal
Micrographic detail of the center of the weld in the second pass (not reheated). Refined ferritic structure. Predominatly acicular ferrite.
38
VIEW
ML00053 / Mar.2017
SAW Longitudinal Seam of X70 Pipe
M - Microalloyed SteelP - Longitudinal Seam Welded PipeAp - SubseaCd - Welding
Cm - Nital Etched Micrography by OMDf - Weld Metal
Micrography of the reheated weld metal, also presenting a refined ferritic structure (with some precipitates).
32
VIEW
ML00053 / Mar.2017
SAW Longitudinal Seam of X70 Pipe
M - Microalloyed SteelP - Longitudinal Seam Welded PipeAp - SubseaCd - Welding
Cm - Nital Etched Micrography by OMDf - Weld Metal