DE2507633C3 - Welding agent for steel coated with aluminum - Google Patents

Description

CaO + MgO
SiO ₂

The invention relates to welding means, e.g. B. composite electrodes that use a flux or encasing a flux within a tubular loop, combinations of a solid Electrode and a flux, core electrodes coated with the flux, in particular Flux for the concealed arc welding of steel coated with aluminum is. The invention particularly relates to welding means for spray coated with molten aluminum Steel.

The term "welding means" as used in the present application means all a combination or mixture of

55 where CaO, MgO and SiO _{2 are} the amounts formed in total when decomposed during welding.

The specified proportions are based on

do the following facts: If the Si content exceeds 1.5% and the Mn content exceeds 1.0%, the weld metal deteriorates the impact strength. When the amount of CaF _{2 is} below 2%, the slag generated during welding becomes extreme

(> s be fluid, and if it exceeds 15%, the The fluidity of the slag can be extremely poor. Both defects require that the welding process is worse through. If the oxide gchalt

ni "he _{a) s} \ 5%, the slag in genn-Vr ^C amount is _Ge, the cooling rate of Sch white metal is not reinforcing the weld metal has poor toughness, and he hen exceeds 50%, the welding can only chwierig be performed. When the basicity was 1.0% nter ^{1 ', the} weld metal ^has poor Zähiakeit, and when it exceeds 12.5%, the weldability is deteriorated. The following examples illustrate the invention.

IO

example 1

The welding means according to the invention are used with known welding means when welding compared with aluminum-coated steel plates of the type listed in Table 3, the Welding equipment according to Table 1 under the welding conditions specified in Table 2 can be used.

Table 4 shows the test results for the weld metals.

Table 1

Composition of welding materials for concealed arc welding

Attempt no. Flux Si (Sinter type) CaO MgO CaF ₂ SiO ₂ Al ₂ O, TiO ₂ Na ₂ O ZrO ₂ CeF Welding electrode Mn Fe Basi
ity 0.15 Mn 4.5
5.0 15th
16 5.0
4.0 11.5
5.0 2.5
1.5 4.5
4.5 2.0
2.3 0.5
4.5 9.0 Si 0.35
0.15 rest
rest According to the invention A.
B. - 5.0 15th 4.5 4.0 2.5 4.5 2.0 4.5 10.0 tr
tr 0.35 rest 1.7
4.2 C. 0.1 7.0 15th 4.0 3.5 4.5 4.5 2.7 4.5 4.0 0.15 0.15 rest 5.0 D. 0.05 0.2 5.0 15th 4.0 8.5 2.5 4.5 1.8 4.5 4.0 t r 0.15 rest 6.3 E. 0.3
0.25 0.15 6.0
12.0 13th
5.5 3.5
2.5 17.5
19th 4.5
4.5 2.0
4.0 2.4
1.5 - - l r 0.2
0.3 rest
rest 2.4 State of the art F.
G 0.6 0.85
075 7.5 14.5 3.5 13.5 2.5 4.0 2.2 - - 0.015
0.015 0.15 rest 1.1
0.9 H 0.2 1.75 6.0 14th 4.5 13.5 2.5 3.5 1.6 3.5 - t r 0.15 rest 1.6 I. 0.6 t r 1.5

The welding electrodes in experiments Nos. A and C are composite electrodes and those in the other experiments are solid Electrodes.

Table 2

Welding conditions for one pass each with double welding

Table 4

Test results of the weld metal

attempt

Composition of
Weld metal

Top and back surface side welding weld impact value of weld metal

(kg-ml

Welding current, amp. 900 750

Arc voltage, V 40

Welding speed, cm / min 40

Table 3

Steel plate that is welded.

Thickness: 12mm.

Quality: 50 kg / mm ² high-strength steel.

composition

Si

Mn

0.15 0.30 (), ^l > 9 0.017 0.015

Pilmilitke of the coated aluminum: KK) μ.

Si

0.25
0.27
0.22
0.29
0.31
0.52
0.43
0.55
0.46

Mn

0.98

0.95

0.86

1.02

1.01

1.50

1.35

1.56

1.32

Al

0.042
0.045
0.043
0.042
0.050
0.118
0.073
0.130
0.087

uEO VE -20

15.7

12.3

15.9

15.3

13.3

6.4

4.0

4.2

6.8

15.0

8.7

15.7

10.3

8.4

3.6

2.7

3.0

3.5

10.1 8.0

15.1 6.1

5.5 1.9 1.4 1.5

It can be seen from the test results of this example that a lowering of the Si and Mn contents results in weld metal with better toughness in the welding means.

^(> 5 example 2

Are steel plates that have been spray-coated with molten aluminum, as shown in the table

are fillet welded using a covered electrode similar to those shown in Table 6 Has specified compositions, the test results shown in Table 7 are obtained.

Table 5

Chemical composition of the base metal in percent by weight

Mn

Film thickness of the

Aluminum, μ

Steel plate covered with molten 0.14 0.40 1.29 0.023 0.010 aluminum with a thickness
is spray-coated from 12 mm

Table 6

Composition of welding agents in archery white rrit an electrode with a flux is coated,%

According to the invention covered electrode with a Durrcsser core and the coated flux)

in 5.0 mm (total switch in the

No. I.

No. 2

No. 3

No. 4

No. 5

Known Nicdrig hydrogen type covered electrode with a Diameter of 5.0 mm

No. 6

No. 7

Si 1.2 1.2 0.8 0.8 1.4 2.2 2.9 Mn - .._ 0.5 - 0.5 0.6 CaCO ₃ 17.7 15th 18th 17.7 11.4 15th 15.75 CaF ₂ 6.3 9 6.6 6.3 4.5 4.8 1.5 MgO 0.45 0.45 0.6 0.45 0.3 0.3 ZrSiO ₄ 0.75 0.75 0.75 0.75 0.6 TiO ₂ 1.5 1.5 1.65 1.5 1.35 2.25 1.2 G 0.75 0.75 0.75 0.75 0.66 0.36 0.6 Na alginate 0.15 0.15 0.15 0.15 0.09 0.09 0.15 Fe rest rest rest rest rest rest rest Basicity 10.3 8.8 10.7 10.3 8.7 5.8 6.8

Table 7

Test results of the weld metal

Welding electrode being tested. Electrode according to the invention

No. 1 No. 2 No. 3

No. 4

No. 5

Commercially available electrode

No. 6

No. 7

Chemical together 0.10 0.11 0.12 0.10 0.11 0.12 0.12 setting of the 0.46 0.48 0.34 0.23 0.24 0.90 1.13 Weld metal 0.57 0.60 0.73 1.08 0.68 1.23 1.42 C. 0.11 0.1 I. 0.15 0.20 0.23 0.36 0.25 Si Mn SnI Λ I

continuation

SchwciUclcktrodi. the μορί ufl becomes the inventor Hcklrode

No. I No. 2 No. 3 No.

No. 5

Commercially available electrode

No. ft

No. 7

Hardness of sweat 238 Hv 236 Hv 230 Hv 221 Hv 228 Hv 283 Hv 328 Hv metals ¹ ) Cross Throat pull test ² ) Tensile test kg / mm ² 55.3 54.7 53.6 56.2 54.5 54.8 55.3 Broken area Dcpo. ground Depo. Depo. Depo. ground ground metal metal metal Results of sweat metals Appearance of the bead ® O O ® ® X X Fluidity of the slag O ® O ® Δ X X Covering property O Δ O O ® X X the slag Peeling off the slag O O O Δ Δ Δ X Overall rating @ O O O O X X Recesses or 0 0 0 0 0 ü Dimples and blowholes Cracks 0 0 0 0 0 0 occur

¹ I Tested in accordance with the Vickers Härletcslgerät with a load of 10 kg. ² I Tested according to JIS Z-3131 procedure

^J ) Tested according to JIS Z-3002 method and compared to the results obtained by melting simple steel plates with commercially available electrodes under the following conditions: (S) = excellent.
O = same.
Δ = somewhat worse.
* = worse

B ice ρ ic 1 3 _1S

Steel plates with the dimensions and compositions given in Table 8 are used with molten aluminum coated with an average film thickness of 70 μ and then fillet welded by »carbon dioxide arc welding ßur.g «. In the examples according to the invention and in the comparative examples, composite Electrodes as listed in Table 9. used and among those given in Table 10 Conditions welded. In Table 11 the Welding results compared. From these results, it can be seen that the properties of the weld claws and the condition of the welded areas

are better when the electrodes according to the invention are used compared with known electrodes .

table

Composition of the hot rolled steel plate, dk is used

(Thickness: 12mmI

0.14

0.40

Mn

1.29

0.009 0.010

Table 9

Chemical composition of welding fluids. Weight- ",,

1 Si Mn CaC Oj I aO CaF ₂ TiOj SiOj . Anc L. C. Si Mn Mon Together 2 αϊ 0.5 0.4 U 12th 4.6 1.0 0.05 <ai OJ set 3 OJ 0.6 n_4 \ 2 6.5 5 1.0 0.05 <0.1 0.3 invention 4th
5 OJ 0.7 0.8 1.0 5.7 S. 1.4 0.05 <ai OJ appropriate
electrode 0.14
0.14 0.4
0.4 0.6
0.4 1.0
1.0 6.46
8.52 5
4.6 1.0
as ί Ni
ICr 1.34
0.4 0.06 0.29
0.29 OJ
0.3 0.16
0.16 6th (N, 1.34 0.14 0.4 0.4 1.0 8.2 3.6 0.8 1 ^he
IMo 0.1 0.06 03 0.3 0.16 7th 0.4 Known 8th 0.6 5.f. OH '0 43 5.0 1.0 0.06 Ό.Ι 0.3 together 9 0.7 1.6 0.4 \ 2 3.1 X 1.6 0.06 ■ 0.1 «U set
electrode 0.7 1.5 1.6 1.2 6.7 1.6 3.0 (1.06 - 0.1 0.3

Hc basi
ity rest
rest
rest
rest 1.4
1.4
1.0
IJ rest 1.5 rest 1.5 rest 3.4 rest 0.7 709 621/33

(ο

9 10

Table 10
Welding conditions

Electricity, amp 300

Voltage, V 36 38

Welding speed, cm / min 37

Flow rate of the shielded

CO ₂ , l / min (CO ₂ ) 25

Horizontal fillet weld

Energy source (jicichstrom, constant voltage, reverse polarity

Table 11
Welding results

Elck- Composition of Black Metal Properties of Occurrence Ab-

trodc [Ciew .-%) welding mclalls from peel

Bulges of the

Sch lad

C Si Mn Sol And. Hardness bubbles cracks

Al (Hv)

Example I 0.09 0.28 0.9 0.24 203 0 0 gul good

2 0.10 0.31 1.08 0.25 235 0 0 good good

3 0.11 0.33 1.30 0.28 248 0 0 gul good

4 0.10 0.38 1.35 0.26 Mo 0.15 263 0 0 good good

Ni 1.8

5 0.08 0.35 1.25 0.20 Cr 0.45 281 0 0 good good

Mo 0.15

6 0.08 0.37 1.20 0.23 Ni 1.8 294 0 0 good good

Cr 0.8
Mo 0.6

Comparative Example 7 0.09 0.55 1.49 0.15 284 0 0 bad good

8 0.10 0.55 1.48 0.20 274 steps. O bad good

on

9 0.12 0.59 1.45 0.18 283 0 0 bad good

5 722

Claims (7)

Patent claims: 1. Welding means for concealed arc welding of steel which is coated with aluminum, characterized in that it contains less than 1.5% by weight Si and / or less than 1.0% by weight Mn, 2 to 15% by weight CaF ₂ and 15 to 50% by weight of a mixture of oxides having a basicity in the range from 1.0 to 12.5, the remainder being essentially iron. 2. Welding means according to claim 1, characterized in that it is 0.1 to 0.3% Si and 0.3 to Contains 0.8% Mn. 3. Welding means according to claim 1, characterized in that it contains less than 1.5% Si and / or less than 1.0% Mn, 2 to 10% CaF ₂ , 6 to 20% CaCO ₃ , 0.3 to 2, 0% of a mixture of MgO and TiO ₂ and less than 1% organic materials, the remainder being iron. 4. Welding means according to claim 1, characterized in that it contains 0.1 to 0.5% Si and / or 0.3 to 1.1% Mn, 4 to 10% CaF ₂ , 0.4 to 4% CaCO ₃ , 0.6 to 2% SiO ₂ , less than 2% CaO and 2 to 6% TiO ₂ , the remainder being essentially iron. 5. Welding means according to claim 1, characterized in that it contains less than 0.15% Si and / or less than 0.35% Mn, 4 to 5% CaF ₂ and 37.5 to 45.7% of a mixture of oxides a basicity in the range 1.7 to 6.3 with the remainder being essentially iron. 6. Welding means according to claim 4, characterized in that it contains 0.8 to 1.4% Si, less than 0.5% Mn, 6.3 to 9% CaF ₂ , 11.4 to 18% CaCO ₃ , 1, 2 to 1.65% of a mixture of MgO and TiO ₂ and 0.75 to 0.9% organic materials, the remainder being essentially iron. 7. Welding means according to claim 4, characterized in that it contains 0.1 to 0.43% Si, 0.7 to 1.0% Mn, 5.7 to 8.52% CaF ₂ , 0.4 to 0.8 % CaCO ₃ , 0.8 to 1.4% SiO ₂ and 3.6 to 5% TiO ₂ , the remainder being essentially iron. 45 materials containing slag forming agents, deoxidizing agents, organic materials, steel and the like in a flux, a welding electrode or the like. Since steel coated with aluminum has excellent corrosion and heat resistance, it is used for many purposes. However, no special welding materials are available for aluminum-coated ones Steel available, so that one has hitherto used the usual known welding means for welding was instructed. If steel that is coated with aluminum is welded using known welding agents Pir Stahl, the affinity of the aluminum for the oxygen that is dissolved in the weld metal is so strong that no consumption of metallic Si and Mn including Fe - Si, Ca - Si and Fe - Mn takes place, materials that will add deoxidation to the welding electrodes and flux. As a result, metallic Si and Mn in excess dissolve in the weld metal. In addition, metallic Si and Mn become in the reduction of the oxides of Si and Mn such as SiO ₂ . CaSiO ₃ , Na ₂ SiO ₃ , MnO, MnO ₂ , MnSiO ₃ and MnCO ₃ , which are present in the flux as slag-forming agents, and these, Si and Mn, also dissolve in the molten metal, so that the crack sensitivity by increasing the Hardenability is increased and the notch toughness is greatly reduced due to the formation of a lath-like troostite structure. The present invention is therefore based on the object. Welding agent for coated with aluminum To create steel, whereby the properties of the weld metal are to be improved by the Si and Mn contents of the weld metal controlled within preferred ranges and where the Weldability should not be deteriorated. This object is achieved according to the invention by a welding means of the type mentioned at the beginning, which is characterized in that it contains less than 1.5% by weight Si and or less than 1.0% by weight Mn, 2 to 15% by weight CaF ₂ and 15 to 50% by weight of a mixture of oxides having a basicity in the range 1.0 to 12.5, the remainder being essentially iron. The term "basicity" used here means the weight ratio of the amount (s) of CaO and / or MgO, based on SiO ₂ , according to the following formula: