Hi,
For dissimilar Welding of Cu-Ni steel with carbon steel by GTAW, first Carbon Steel side may be overlayed first with ERNi-1 or ERNiCu-7 and then weld with AWS A5.14 ERNiCu-7 (N04060) . Also please find below the details might be useful to you.
Gas Tungsten Arc Welding
The GTAW process is the preferred process for welding thin gage material, 1/16 in. (1.6mm) and less, but can be a good choice for gages up to about 1/8 in. (3.2mm). The all-position operability characteristic makes it an excellent process for pipe welding, particularly for small diameter pipe and the root pass of all pipe diameters. After a GTAW root pass in heavier pipe, the weld is often completed by GMAW or SMAW. Automatic GTAW equipment is available for applications such as tube to tube sheet welds, orbital pipe welding and joining sheet gages.
Cu-Ni welds made without the addition of the deoxidized filler material very often have excessive porosity that is not apparent on the weld surface. For this reason autogenous GTA welds should be avoided. Other good welding practices to avoid porosity include a short arc, about 0.03 inches (0.8mm) and ample weld metal shielding to exclude air from the molten weld metal. Argon is the usual shielding gas and preferred for purging the inside of pipes during root pass welding.
Representative parameters for GTAW Cu-Nis are shown in Table 4. As with the other arc welding processes, the high conductivity, lower nickel alloys require currents on the high end of the range. Where possible, copper or Cu-Ni backing bars are favored.
Table 4. Representative Gas Tungsten Arc Welding
ERCuNi filler, direct current, straight polarity
Thickness (in.) Electrode Size (in.) Filler Wire (in.) Current (amps) Argon Flow (cfh)
1/16 1/8 1/16 100 - 140 15 - 20
1/8 1/8 1/8 140 - 200 15 - 20
1/4 1/8 1/8 - 3/16 180 - 260 20 - 30
3/8 1/8 - 3/16 1/8 - 3/16 260 - 320 20 - 30
1/2 3/16 1/8 - 3/16 320 - 400 20 - 30
Dissimilar Metal Joining and Weld Overlaying
Suggested filler metal for joining Cu-Ni alloys to some of the commonly combined other alloys is shown in Table 6. The listing is not intended to be exclusive in that welding procedures could be developed using filler metals not listed.
Table 6 Filler Metals for Dissimilar Metal Welds
Metal to be joined to Cu-Ni SMAW (UNS) GMAW and GTAW (UNS) Comments
ANSW/AWS A5.6 ANSI/AWS 5.7
Copper ECuNi (W60715) or ECuA1-A2 (W60614) ERCuA1-A2 (71580) or ERCuA1-A2 (C61800) Preheat to 1000°F (540°C)
Phosphor bronzes ECuSn-A (W60518) ERCuSn-A (C51800) -
All bronzes ECuA1-A2 (W60614) ERCuNl (C61800) -
ANSI/AWS A5.11 ANSI/AWS A5.14
Carbon steel ENiCu-6 (W84190) ERNiCu-7 (N04060) Steel side may be overlayed first with ERNi-1 or ERNiCu-7
Austinetic stainless steels ENi-1 (W82141) or ENiCrFe-2 (W86133) ERNi-1 (N02161) or ERNiCr-3 (N06082) Stainless side may be overlayed first with ERNi-1
The 70-30 Cu-Ni welds have a limited tolerance for dilution by iron. Welds with more than about 10% iron tend to have excessive fissures and develop hot cracks. The ENiCu-7 and ERNiCu-7 fillers (65Ni-Cu) have a higher tolerance for iron and are used in joining to carbon steels. However, they are not a good choice in welding to stainless steels because of limited tolerance for dilution by chromium.
Often a very useful step in making Cu-Ni dissimilar metal welds is to overlay or butter the other metal with nickel, nickel-copper or any other appropriate filler shown in Table 6. In applying Cu-Ni overlays on steel, the usual practice is to apply a first layer with ERNi-1 or ERNiCu-7 and then ERCuNi for subsequent layers. Although a high alloy barrier layer is standard, it is possible to apply ERCuNi by GMAW directly on carbon steel with carefully controlled welding procedures designed to achieve relatively low iron dilution on the first layer.
The submerged arc welding (SAW) process is ideally suited for overlaying large surface areas. Commercial submerged arc fluxes are available for all the nickel, nickel-copper and Cu-Ni filler metals. In overlaying carbon steel, the first layer is applied using either an ERNi-1 or ERNiCu-7
filler metal followed by subsequent layers of ERCuNi to reach the needed thickness or composition.
Brazing with BAg-1a, BAg-1 and BAg-2 is suitable for joining Cu-Ni to any other copper alloy.
Thanks & Regards,
(Karthik)
Karthikeyan.S
QA/QC Manager
German-Thai Boiler Engineering Cooperation Limited.
Rayong Factory ;
379 Moo.6 Soi 8, Tambol Pananikom,
Nikompattana, Rayong 21180 THAILAND
Tel : +66 38 897 035-9 Ext. 137
Fax : +66 38 897 034
Hand Phone: 0066 892512282
From: LeONarD P <metpick@gmail.com>
To: Materials & Welding <materials-welding@googlegroups.com>
Sent: Monday, February 6, 2012 3:15 PM
Subject: [MW:13616] Welding 90Cu-10Ni to Carbon Steel.
Dear Expert,
If I will qualified WPS with 90Cu+10Ni(P-No.34) weld to Carbon
steel(P-No.1);
By GTAW process. Can I choose the type of welding rod for
welding ? .Please reply
me in the light of ASME SEC IX.
Thanks in advance
Sutthipong K.
--
To post to this group, send email to materials-welding@googlegroups.com
To unsubscribe from this group, send email to materials-welding+unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
No comments:
Post a Comment