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Weld Shapes

Preparation and execution of welding must be performed in such a way that the weld metal for the base material does not fuse the cladding. This prevents the formation of brittle or hot-crack sensitive weld metal. During pre-processing of the weld edges the actual thickness of the cladding needs to be taken into consideration. Any filling of the base material weld should be executed from the base material side, if possible, in order to avoid contamination of the cladding material. Titanium and steel cannot be directly fusion-welded to each other due to brittle intermetallic phases. Therefore, batten straps are chosen to join titanium clad plates.

Butt Welds

Fillet Welds

The bonding of the cladding in our roll-bonded clad plates is so strong, even considerably over dimensioned fillet welds do not cause any detachment of the cladding material.
However, the standards for the ultrasonic testing of clad plates allow certain bonding defects. When welding fillet welds onto the cladding material, the plate must be carefully checke
for proper bonding by ultrasonic testing in the area of the weld before and after the welding operation.
Removal of the cladding with subsequent weld cladding to prepare vertical connection is only required in areas where bonding defects have been found in the ultrasonic test.
Any melting through the cladding has to be compensated for by a corresponding over-alloyed filler metal.

Recommended filler metals for the welding of clad materials made of special steels, non-ferrous matals and alloys

Cladding Filler Metal Type Sing-pass ESSC (SASC) Strip
Alloy Type EN Material
Number
Multi-Pass (GTAW, FMAW, FCAW)
Buffer-EN ISO Buffer - AWS Subsequent Passes -EN ISO Subsequent Passes -AWS
Alloy 800 1.4876 NI 66 25 (NiCr-22Mo9Nb) NiCrMo-3 NI 66 25 (NiCr-22Mo9Nb) NiCrMo-3 NI 66 25 (NiCr-22Mo9Nb) NiCrMo-3
Alloy 904L 1.4539 23 12L 309L 20 25 5 CuL 385 NI 66 25 (NiCr-22Mo9Nb) NiCrMo-3
Alloy 28 1.4563 23 12L 309L 27 31 4 CuL 383 NI 66 25 (NiCr-22Mo9Nb) NiCrMo-3
Alloy 926 1.4529 NI 66 25 (NiCr-22Mo9Nb) NiCrMo-3 NI 66 25 (NiCr-22Mo9Nb) NiCrMo-3 NI 66 25 (NiCr-22Mo9Nb) NiCrMo-3
Alloy 20 2.466 NI 66 25 (NiCr-22Mo9Nb) NiCrMo-3 NI 66 25 (NiCr-22Mo9Nb) NiCrMo-3 NI 66 25 (NiCr-22Mo9Nb) NiCrMo-3
Alloy 825 2.4858 NI 66 25 (NiCr-22Mo9Nb) NiCrMo-3 NI 66 25 (NiCr-22Mo9Nb) NiCrMo-3 NI 66 25 (NiCr-22Mo9Nb) NiCrMo-3
Alloy 625 2.4856 NI 66 25 (NiCr-22Mo9Nb) NiCrMo-3 NI 66 25 (NiCr-22Mo9Nb) NiCrMo-3 NI 60 59 (NiCr-23Mo16) NiCrMo-13
Alloy C22 2.4602 NI 60 22 (NiCr-21Mo13W3) NiCrMo-10 NI 60 22 (NiCr-21Mo13W3) NiCrMo-10 NI 60 22 (NiCr-21Mo13W3) NiCrMo-10
Alloy C4 2.4610 NI 64 55 (NiCr-16Mo16T1) NiCuMo-7 NI 64 55 (NiCr-16Mo16T1) NiCrMo-7 NI 64 55 (NiCr-16Mo16T1) NiCrMo-7
Alloy C276 2.4819 NI 64 55 (NiCr-16Mo16T1) NiCuMo-7 NI 64 55 (NiCr-16Mo16T1) NiCrMo-7 NI 62 76 (NiMo-16Cr15Fe6W4) NiCrMo-4
Alloy 50 2.4605 NI 60 59 (NICr-23Mo16) NiCrMo-13 NI 60 59 (NICr-23Mo16) NiCrMo-13 NI 60 59 (NiCr-23Mo16) NiCrMo-13
Alloy B2 2.4617 - - - - NI 64 55 (NiCr-16Mo16T1) NiCrMo-7
Alloy 600 2.4816 NI 60 82 (NiCr-20Mn3Nb) NiCr-3 NI 60 82 (NiCr-20Mn3Nb) NiCr-3 NI 60 82 (NiCr-20Mn3Nb) NiCr-3
Alloy 400 2.4360 NI 40 60 (NiCu30Mn3T1) NiCu-7 NI 40 60 (NiCu30Mn3T1) NiCu-7 NI 40 60 (NiCu30Mn3T1) NiCu-7
Alloy 200 2.4066 NI 20 61 (NiTi3) Ni-1 NI 20 61 (NiTi3) Ni-1 NI 20 61 (NiTi3) Ni-1
Alloy 201 2.4068 NI 20 61 (NiTi3) Ni-1 NI 20 61 (NiTi3) Ni-1 NI 20 61 (NiTi3) Ni-1
SE-Cu 2.0070 NI 40 60 (NiCu30Mn3T1) NiCu-7 NI 40 60 (NiCu30Mn3T1) NiCu-7 Welding of Cu and Cu -Alloys onto carbon steel
without buffer layer is not recommended.
SF-Cu CW024A NI 40 60 (NiCu30Mn3T1) NiCu-7 NI 40 60 (NiCu30Mn3T1) NiCu-7
Alloy CuNi 90/10 CW352H NI 40 60 (NiCu30Mn3T1) NiCu-7 NI 40 60 (NiCu30Mn3T1) NiCu-7
Alloy CuNi 70/30 CW354H NI 40 60 (NiCu30Mn3T1) NiCu-7 NI 40 60 (NiCu30Mn3T1) NiCu-7
Titanium Grade 1 3.7025 Titanium must not be diluted with steel,
therefore only batten straps
3.7025 ERTi-2 - -
Titanium Grade 2 3.7035 3.7035 ERTi-3 - -

1. Over-alloyed, for maximum corrosion resistance – e.g. ERNiCrMo-13

2. Matching, at least two passes are required

3. for higher electrical conductivity

Welding Execution

Cleaning

The welding of the cladding layer requires the same cleanliness as when working with solid materials of a similar composition.
Consequently, chippers, brushes etc., of stainless steel are to be used. In the case of Ni and Ni-alloys, prevention of all sulfur-containing contaminations is of utmost importance.
Therefore only grinding materials with sulfur-free bonding agents (synthetic resin adhesion) should be used.

Weld Design

The full alloy content (or a limitation to a maximum of 5% Fe for Ni or Alloy 400) is often only achieved in the third pass.
Consequently, in most cases a weld reinforcement of 2 up to 3 mm is allowed on the side of the cladding material in order to obtain sufficient room for three passes.
If a limit is set for the weld reinforcement, the first and the second pass must be heavily ground before welding is continued.

Preheating and Heat Control

- Welding of the base material    We recommend using EN 1011-2 for calculating the minimum preheating temperature, which depends on the chemical analysis, the thickness and the welding process employed. - Welding of the buffer    Most of the buffers are welded using austenitic filler materials which give off very little hydrogen to the base material.
   According to experience, the reheating temperature may therefore be lower than calculated.
   - approx. 50°C lower for SMAW
   - up to 100°C lower for GMAW, GTAW, FCAW and ESSC/SASC (SAW) strip welding.

Welding of the Cladding Material

An overview of the heat control during welding of the cladding material is given in the table below.

Cladding Filler Preheating min. °C Imterpass temp. max. °C
13% Cr-steels Austenitic / Matching - 200
150 250
CrNi-steels Matching None 150
Ni and Ni-alloys Matching None 150
Cu Matching > 400 500
CuNi and NiCu-alloys Matching None 150
Ti Matching None 100

Stress-Relief Annealing

Generally, stress-relief annealing of roll-bonded clad plates is only necessary as a requirement of the base material. By stress-relief annealing the properties of the cladding and the corresponding weld metal may deteriorate due to precipitation of carbides, intermetallic phases etc. Therefore, stress-relief annealing is to be avoided if possible or adjusted to the base and cladding materials. Only grinding materials with sulfur-free bonding agents (synthetic resin adhesion) should be used.

Post-Treatment of the Welds

Smoothening of the weld to prevent deposits (crevice corrosion), pickling to remove annealing colors or similar measures may be required, depending on the type of the cladding material and the attacking medium.