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Weld defects and precipitates of deposited metal in 9Ni steel welded joint

Chengyong Ma
Chengyong Ma
, 
Yanchang Qi
Yanchang Qi
, 
Yuqing Zhang
Yuqing Zhang
, 
Zhiquan Wu
Zhiquan Wu
 oraz 
Xin Zhang
Xin Zhang
   | 27 maj 2022
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Data publikacji: 27 maj 2022
Zakres stron: 25 - 48
Otrzymano: 16 sie 2021
Przyjęty: 19 gru 2021
DOI: https://doi.org/10.2478/msp-2022-0007
Słowa kluczowe
© 2021 Chengyong Ma et al., published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Fig. 1

Tensile specimen of deposited metal and its sampling position
Tensile specimen of deposited metal and its sampling position

Fig. 2

Drawing of weld metal impact sampling
Drawing of weld metal impact sampling

Fig. 3

Position diagram of welding joint hardness test position
Position diagram of welding joint hardness test position

Fig. 4

Schematic diagram of welding groove
Schematic diagram of welding groove

Fig. 5

Microstructure and electron microscopic structure of 9Ni steel as observed by optical microscope (A) and SEM (B). SEM, scanning electron microscopy
Microstructure and electron microscopic structure of 9Ni steel as observed by optical microscope (A) and SEM (B). SEM, scanning electron microscopy

Fig. 6

Macro diagram of metal weld bead
Macro diagram of metal weld bead

Fig. 7

Penetration test of molten metal: (A) 1#; (B) 2#; (C) 3#
Penetration test of molten metal: (A) 1#; (B) 2#; (C) 3#

Fig. 8

Pore image under optical microscope
Pore image under optical microscope

Fig. 9

Slag interlocking between welding channels
Slag interlocking between welding channels

Fig. 10

Intergranular hole
Intergranular hole

Fig. 11

Crack morphology and its energy spectrum of 3# deposited metal: (A) crystal crack; (B) morphology of crystal crack; (C) energy spectrum
Crack morphology and its energy spectrum of 3# deposited metal: (A) crystal crack; (B) morphology of crystal crack; (C) energy spectrum

Fig. 12

Macromorphology of 2# deposited metal
Macromorphology of 2# deposited metal

Fig. 13

Microstructures of the root and surface of the deposited metal: (A) the root; (B) the surface
Microstructures of the root and surface of the deposited metal: (A) the root; (B) the surface

Fig. 14

Microstructure of three kinds of deposited metals: (A) 1#; (B) 2#; (C) 3#
Microstructure of three kinds of deposited metals: (A) 1#; (B) 2#; (C) 3#

Fig. 15

Austenite grain boundary microstructure of three kinds of deposited metals: (A) 1#; (B) 2#; (C) 3#
Austenite grain boundary microstructure of three kinds of deposited metals: (A) 1#; (B) 2#; (C) 3#

Fig. 16

Metallographic microstructure of the welding channels for the 2# deposited metal
Metallographic microstructure of the welding channels for the 2# deposited metal

Fig. 17

Scanning position and the line scanning result of the element
Scanning position and the line scanning result of the element

Fig. 18

Variations among Ni, Cr, and Mo contents within the 2# deposited metal weld: (A) Ni, (B) Cr, (C) Mo
Variations among Ni, Cr, and Mo contents within the 2# deposited metal weld: (A) Ni, (B) Cr, (C) Mo

Fig. 19

Variation among Fe and C contents within the 2# deposited metal weld
Variation among Fe and C contents within the 2# deposited metal weld

Fig. 20

Precipitation and energy spectrum of granular Nb carbides
Precipitation and energy spectrum of granular Nb carbides

Fig. 21

Precipitation and energy spectrum of long strip Nb carbides
Precipitation and energy spectrum of long strip Nb carbides

Fig. 22

Ellingham chart [20]
Ellingham chart [20]

Fig. 23

Morphology and energy spectrum of WC precipitates
Morphology and energy spectrum of WC precipitates

Fig. 24

Precipitation of Al and Ti oxides
Precipitation of Al and Ti oxides

Fig. 25

Precipitation of Nb carbide
Precipitation of Nb carbide

Fig. 26

Morphology and energy spectrum of 1# deposited metal precipitates
Morphology and energy spectrum of 1# deposited metal precipitates

Fig. 27

Morphology and energy spectrum of 2# deposited metal precipitates
Morphology and energy spectrum of 2# deposited metal precipitates

Fig. 28

Morphology and energy spectrum of 3# deposited metal precipitates
Morphology and energy spectrum of 3# deposited metal precipitates

Fig. 29

Morphology and EDS analysis of precipitates of deposited metal. (A) 3#SEM, (B) 3#EDS. EDS, energy dispersive spectrometer; SEM, scanning electron microscopy
Morphology and EDS analysis of precipitates of deposited metal. (A) 3#SEM, (B) 3#EDS. EDS, energy dispersive spectrometer; SEM, scanning electron microscopy

Fig. 30

Zigzag grain boundary
Zigzag grain boundary

Fig. 31

Intergranular cracking and precipitates of the three deposited metals: (A) SEM, (B) First measuring point and element analysis, (C) Second measuring point and element analysis, (D) Third measuring point and element analysis. SEM, scanning electron microscopy
Intergranular cracking and precipitates of the three deposited metals: (A) SEM, (B) First measuring point and element analysis, (C) Second measuring point and element analysis, (D) Third measuring point and element analysis. SEM, scanning electron microscopy

Fig. 32

Precipitate morphologies: (A, C, E) root of 1#, 2#, 3# welding; (B, D, F) surface of 1#, 2#, 3# welding
Precipitate morphologies: (A, C, E) root of 1#, 2#, 3# welding; (B, D, F) surface of 1#, 2#, 3# welding

Fig. 33

Quantity of precipitated phases of the three deposited metals
Quantity of precipitated phases of the three deposited metals

Fig. 34

Intergranular crack in tensile test: (A) 1#; (B) 2#; (C) 3#
Intergranular crack in tensile test: (A) 1#; (B) 2#; (C) 3#

Fig. 35

Longitudinal distribution of hardness of deposited metal
Longitudinal distribution of hardness of deposited metal

Fig. 36

SEM morphologies of impact fracture of deposited metal: (A) 1#, (B) 2#, (C) 3#. SEM, scanning electron microscopy
SEM morphologies of impact fracture of deposited metal: (A) 1#, (B) 2#, (C) 3#. SEM, scanning electron microscopy

Composition of deposited metal precipitates (wt%)

Precipitate Nb Ni Al Ti
1 33.19 15.82 14.27 19.71
2 47.19 14.99 9.47 15.29
3 46.16 18.98 8.80 13.53

Chemical composition of 9Ni steel/wt.%

C Si Mn S P Ni Fe
0.05 0.45 0.62 0.001 0.0024 9.35 Balance

Composition of 2# deposited metal precipitates (wt%)

NO. Nb Ni Cr Ti
2# 58.61 15.56 8.09 8.92

Mechanical properties of 9Ni steel

Tensile Strength (Rm/MPa) Yield strength (Rp0.2/MPa) Elongation (A/%) Impact absorbing energy Akv/J (−196°C)
727 668 27 231, 240, 233234.7

Chemical composition of the weld metal (wt%)

No. C Si Mn Nb W Cr Mo P/S Ti Ni
1# 0.03–0.05 0.2–0.4 3.2–3.8 1.10 1.6–1.8 12.5–13.0 7.4–7.7 ≤ 0.015 0.10–0.13 Bal.
2# 0.03–0.05 0.2–0.4 3.2–3.8 1.30 1.6–1.8 12.5–13.0 7.4–7.7 ≤ 0.015 0.10–0.13 Bal.
3# 0.03–0.05 0.2–0.4 3.2–3.8 1.52 1.6–1.8 12.5–13.0 7.4–7.7 ≤ 0.015 0.10–0.13 Bal.

Precipitates’ composition of 3# deposited metal (wt%)

Precipitates S Cr Mn Fe Ni
Content 2.50 13.42 3.59 4.19 74.34

Composition of 3# deposited metal precipitates (wt%)

NO. Nb Ni Cr Ti
3# 85.58 7.08 3.95 3.11

ΔG values at different temperatures

T/K 400 600 800 918 1,063
−147.6 −142.2 −136.8 −125.4 −118.0

Impact resistance of deposited metal

No. Akv/J
1 132, 133, 126, 140, 126
2 115, 123, 119, 112, 113
3 80, 89, 82, 95, 92

Welding parameters of deposited metal

Welding current (I/A) Welding voltage (U/V) Welding speed (v/cm/min) Inter channel temperature (T/°C) Heat input (E/kJ/cm)
95 27 13 100 a

Composition of 1# deposited metal precipitates (wt%)

NO. Nb Ni Cr Fe
1# 19.03 53.84 11.20 4.54

Tensile properties of welding rod deposited metal

No. Tensile Strength (Rm) MPa Yield strength (Rp0.2) MPa Elongation (A)% Section shrinkage (Z)%
1# 687 429 33.1 33
2# 705 478 32.5 34
3# 710 482 27.5 30
eISSN:
2083-134X
Język:
Angielski
Częstotliwość wydawania:
4 razy w roku
Dziedziny czasopisma:
Materials Sciences, other, Nanomaterials, Functional and Smart Materials, Materials Characterization and Properties
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