CH648231A5 - Molybdaenarme welding materials. - Google Patents

Description

648 231

2nd

PATENT CLAIMS 1. Welding materials, in particular for manual electrode welding, submerged arc electroslag, electro gas and inert gas welding, characterized in that they produce a pure weld metal with the following analysis limits:

C:

0.01 to 0.15% by weight

Mn:

0.7 to 1.8% by weight

Si:

0.05 to 0.6% by weight

Cr:

0.01 to 1.0% by weight

Mon:

0.05 to 0.4% by weight

Ti:

0.01 to 0.03% by weight

B:

Traces up to 0.01% by weight

10th

the sum of Cr + Mo is not greater than 1.2% by weight.

15

2. Welding materials according to claim 1, characterized in that they result in a pure weld metal with the following analysis limits:

C: 0.01 to 0.15% by weight

Mn: 0.7 to 1.6% by weight

Si: 0.05 to 0.6% by weight

Cr: 0.1 to 0.8% by weight

Mo: maximum 0.1% by weight

Ti: 0.01 to 0.03% by weight

B: traces up to 0.01% by weight.

3. Welding materials according to patent claims 1 or 2, characterized in that they produce a pure weld metal that has at least 70 surface percent acicular ferrite in the structure and that results in no or only a slight decrease in the impact energy according to DIN 50 115 during thermal aftertreatment.

The invention described here relates to welding units, together with various oxide cores, to form materials, in particular for manual electrode welding, unacicular ferrite. Well-balanced amounts of terpulver-Elektroschlacke-Elektrogas- und Schutzgas- Ti + B form a uniformly developed structure of fine

Welding. acicular ferrite.

In the literature of the past 10 years there are various 25

Publications have become known, which have as their alloy base a combination of the

report on Ti-B alloyed welding materials. setting

The advantage of such Ti-B alloyed welding materials lies particularly in their applicability for thick one to C-Mn-ai-Mo-1 i-B

Three-layer welding with high heat input, d. H. at 30

Submerged arc and electroslag welding. Overview of welding literature: see Masumoto IIW-Doc. XII694-79

In practice, the Mn-Mo-Ti-B-alloyed microstructures with high acicular ferrite contents and low weld metal (type B) have been used in welding technology to date

Proeutectoid ferrite content. This in turn leads to the unobserved property that single-layer welds have high impact values at low temperatures, such as 35 better notched toughness values than multi-layer welding

especially for inlay welding with classic solutions.

Welding materials cannot be reached. The one blown by subsequent welding beads

The mode of action of the Ti + B alloy is as follows. Structure shows worse notched bar impact values than structure,

explains: The formation of TiN allows dissolved B to undergo no thermal aftertreatment,

the austenite grain boundaries because the formation 40 The following three tables illustrate:

is suppressed by BN. The B-excretion in turn Table 1.1: The chemical composition of six reduces the grain boundary energy and thus suppresses the investigated weld metal (including the base material

Formation of proeutectoid ferrite. Furthermore, TiN fes) of type B according to the prior art,

Table 1.1

Chemical composition of the weld metal 1 to 6 and the base material PSX 70 (type B)

Sample No.

c

Si

Mn

P

S

Mo y

Al

Nb

Ti

B

1

(FD80-63)

0.070

0.295

1.31

0.0159

0.0084

0.155

0.0547

0.039

0.025

0.0127

0.0026

2nd

(FD80-64)

0.052

0.254

1.11

0.0135

0.0088

0.258

0.0409

0.0295

0.015

0.0175

0.0031

3rd

(FD80-65)

0.074

0.329

1.35

0.0162

0.0093

0.139

0.0603

0.0513

0.026

0.0159

0.0023

4th

(FD80-69)

0.071

0.367

1.65

0.0155

0.0112

0.202

0.0526

0.0446

0.0250

0.0256

0.0050

4W

(FD80-66) 5

(FD80-67)

0.068 0.068

0.318 0.325

1.29

1.30

0.0153 0.0159

0.0099 0.0095

0.175 0.157

0.0561 0.0530

0.0450 0.0394

0.025 0.0237

0.0167 0.0152

0.0026 0.0026

6

(FD80-68)

0.062

0.340

1.27

0.0150

0.0084

0.155

0.0513

0.0382

0.0228

0.0154

0.0023

GW PSX 70

0.101

0.345

1.54

0.0160

0.0111

-

0.0740

0.0565

0.0374

-

-

3rd

648 231

Table 1.2: The results of tensile tests according to DIN 50 145 of the above samples and

Table 1.3: The results of the impact energy according to DIN 50 115 of the same samples.

The decrease in the notched bar impact work in multi-layer welding is clearly visible.

Table 1.2 Tensile test according to DIN 50 145 / unannealed sample form B X 40

Sample No.

Rm

(N / mm2)

^ p0.2

(N / mm2)

A5 (%)

Z (%)

Fracture position

1

(FD80-63)

717

630

16.5

52.8

1/3

2nd

(FD80-64)

657

577

21.2

64.1

1/2

3rd

(FD80-65)

4th

(FD80-69)

689 725

583 598

21.5 20.5

62.5 64.1

1/3 1/2

4W

(FD80-66)

671

568

21.7

62.5

1/2

5

(FD80-67)

661

556

21.0

62.5

1/2

6

(FD80-63)

669

577

21.5

60.9

1/2

GW PSY 70

663

555

24.6

68.0

1/2

Table 1.3

Impact test according to DIN 50 115 / not annealed Sample form: ISO-V sample

No.

Notched bar impact work (J) (seam center)

—20'C

-40 ° C

-60 ° C

93

45

27th

1

141

114

75

56

30th

27th

(FD80-63)

108

49

23

45

22

2nd

42

41

33

29

-

(FD80-64)

37

31

141

74

54

3rd

148

139

101

94

74

66

(FD80-65)

128

107

70

98

98

35

4th

107

114

130

90

41

42

(FD80-69)

136

43

51

151

125

71

4W

146

137

116

122

73

64

(FD80-66)

115

125

47

143

65

45

5

93

113

95

80

35

36

(FD80-67)

102

80

27th

80

74

31

6

163

117

55

62

27th

28

(FD80-68)

109

57

26

45

30th

10th

7

45

45

37

33

12

13

46

32

13

The attached drawings show:

in Fig. 1

the geometry of the seam preparation and (in the order of the reference numbers entered on it) the sequence of the weld layers in accordance with the weld metal specified in Tables 1.1 to 1.3;

in Figs. 2 and 3

the geometry of the seam preparation and (in the order of the reference numerals entered on it) the sequence of the welding positions in accordance with the welding goods specified in Tables 2.1 and 2.2, as well as a diagram of the values of the impact energy obtained with the welding goods at a specific test temperature; and in Figs. 4 and 5

15 diagrams of the tensile strength (Rm), the yield strength (Re) and the values of the impact energy obtained at a certain test temperature for the weld metal specified in Tables 3.1 and 3.2 and with a heat treatment as a parameter.

20 The same also applies to welds that have been subjected to so-called stress relief annealing (550 to 640 "C, holding time 2 min / mm sheet thickness).

With stress relieving, it can be observed that caterpillars with a primary structure experience a significant drop in notch impact strength and caterpillars with a grained structure experience an even more pronounced drop in notch impact strength.

The following two tables explain:

Table 2.1: Information on impact test according to DIN 50 115 (not annealed) and

Table 2.2 corresponding information annealed. The corresponding results are shown in the drawings, FIGS. 2 and 3.

This is in line with the long-known phenomenon that Mo-alloyed weld metal gives poorer notched bar impact values when stress relieved at low temperatures than when welded.

30th

35

40

50

55

60

65

Table 2.1 TJP-T andem method Notched impact test according to DIN 50 115 Sample form: ISO-V sample

Wire quality:

Wire diameter:

Powder:

Base material:

Sampling:

Heat treatment:

FLUXOCORD 35.2 (type B)

4.0 mm

OP 121 TT

PSX 70

Sample center not annealed

Table 2.2 UP tandem method Impact test according to DIN 50 115 Sample form: ISO-V sample

Wire quality:

Wire diameter:

Powder:

Base material:

Sampling:

Heat treatment:

FLUXCROD 35.2 (type B)

4.0 mm OP 121 TT PSX 70 sample center stress relieved 2 h / 580 ° C. The same observation also applies to tandem welds with two or three wires, with the arc of the subsequent wire thermally influencing the primary structure of the first bead if the wire spacing is too large. Here, too, noticeably worse notch impact values can be observed than with very small wire gaps, in which both wires produce a single weld pool.

Reports have recently become known which work with the alloy base C-Mn-Si-Ti-B, whereby

648 231

but it is clear from these reports that in this case the weld metal must contain particularly tight tolerances in the content of Ti, B, N and O in order to achieve the mechanical quality values of the Mo-containing welding materials. The Ti content is particularly important here, since this element has the task of producing the optimal microstructure with a high content of acicular ferrite. With the Mo-alloyed welding materials, the Mo takes on this task,

without having to keep his salary within very narrow limits.

It was completely surprising to find that welding materials, the weld metal of the analysis type C-Mn-Si-Cr-Ti-B with traces of Mo (A2) and C-Mn-Si-Cr-Mo-B-Ti (A3 ) (whereby in the first case the Mo comes from Mo traces contained in the raw materials of the filling powder or in the tubular iron coating and in the latter case the Mo has been significantly reduced compared to the previous welding materials), have significantly more favorable toughness properties after thermal treatment than Welding materials with welding goods of the type C-Mn-Si-Mo-Ti-B (type B), according to the state of the art.

The welding materials according to the invention are characterized in the preceding claims 1 and 2.

The thermal treatment refers here both to real post-treatments such as stress relieving or tempering, and to post-treatments of the structure by subsequently applied welding beads.

This is all the more surprising since to date hardly any Mn-Cr alloyed weld metal is known for submerged arc, inert gas and electrode manual welding. In addition, such weld metal only has increased tensile strength at elevated temperatures.

The following tables show:

Table 3.1: Analysis and installation for tensile tests according to i5 DIN 50 145 and for impact tests according to DIN 50 115 of a welding material of type A 2 and

Table 3.2: Corresponding details of a welding material of type A 3 according to the invention. 20 The corresponding results are shown in the drawings, FIGS. 4 and 5.

The slight decrease in the impact strength values is clearly visible.

Table 3.1 Wire type A2 / OP 121 TT welded connection in position and opposite position on PSX 70

C.

Mn

Si

P

S

Cr

Mon

Ti

B

V

Sweat

0.073

1.38

0.30

0.018

0.010

0.19

-

0.02

0.005

0.04

PSX 70

0.084

1.55

0.35

0.018

0.009

-

-

-

0.004

0.08

Table 3.2 Wire type A3 / OP 121 TT welded connection in layer and counterpart on PSX 70

C.

Mn

Si

P

S

Cr

Mon

Ti

B

V

Sweat

0.074

1.45

0.35

0.019

0.012

0.17

0.08

0.01

0.005

0.05

PSX 70

0.084

1.55

0.35

0.018

0.009

-

-

-

0.004

0.08

The new welding materials according to the invention with the weld metal of the type C-Mn-Si-Cr-Ti-B with traces of Mo (type A2) and C-Mn-Si-Cr-Mo-Ti-B with reduced Mo content (type A3) therefore have the following advantages over the C-Mn-Si-Mo-Ti-B types (B types):

- Better notched bar impact values in position - counter position - weldings at lower temperatures.

- Better notch impact values for multi-layer welding.

- Better notch impact values for tandem welds with wire gaps greater than 20 mm.

- Better notched bar impact values after stress relief annealing for face-to-face welding and multi-layer welding.

- If desired, lower tensile strength of the weld good, since the Cr has less strength-increasing effect than the Mo.

The present results were preferably determined using submerged arc welding. Initial tests with other welding processes have shown that such welding filler materials can also be used for electro-slag-electro gas and inert gas welding and also have the advantages described here. Furthermore, the use of such welding materials is not limited to wires (cored or solid wires), they can also be produced in the form of filled strips (for submerged arc and electroslag welding). The production of metal powder additives for submerged arc and electroslag welding in the specified analysis tolerances is also possible.

60

s

5 sheets of drawings