Thread: Welding bisalloy

Are you welding the plates together or are they a wear plate being welded onto mild steel?

http://bisalloy.yurtest.net/applicat...20bisplate.pdf

Cheers

Justin

Yes I am welding the plates together.
There is approx 3 meters of weld.
The sample has approx 12-14 mm leg length fillet.

I will get some pics of the job when I can.

Thanks
Andrew

Here is a pic of the job in question
mini-Picture 004.jpg

It is the keel off a large racing yacht.
The rectangular hole in the face is where a fabricated box section protrudes through the flange.
Both the box section 12mm and the flange 25mm are bisalloy
It is then welded on both sides. Flush on the face of the flange (V grooved ) and a fillet on the back edge.
The stud that you can see protruding from the flange is one of 12, M25 stainless studs which are used to hold the keel to the bottom of the boat.
The keel assembly weighs approx 2.5 tons

I know I haven't explained it that well.
The only reason that I am going to do the job is to learn a little about welding bisalloy.
The material is bisalloy 80.

Thanks
Andrew

OOPS I hope I didn't do that.
If I did I didn't mean to.

Hi, I am not sure why you are attempting this job if you have no experience in it. It also suggests that no body else there where you work has either. Dealing with a heavy weighted keel as what you say is not something to experiment with. If you are to learn on this welding job it should be overseen by someone with the right experience or not attempted at all.

This type of job may require some form of weld test ( xray etc ) in order to be approved before fitting up and you should at least find out. The onus will fall on the company taking the job on and i would not want to tied into it if something went wrong and your lack of experience was the contributing factor. Its great to learn but make sure you have the right people to teach you and if the company fires a bullet in your back if it "keels over'' ( i could not resist).
Be wary.

Originally Posted by Dobre

Hi, I am not sure why you are attempting this job if you have no experience in it. It also suggests that no body else there where you work has either. Dealing with a heavy weighted keel as what you say is not something to experiment with. If you are to learn on this welding job it should be overseen by someone with the right experience or not attempted at all.

This type of job may require some form of weld test ( xray etc ) in order to be approved before fitting up and you should at least find out. The onus will fall on the company taking the job on and i would not want to tied into it if something went wrong and your lack of experience was the contributing factor. Its great to learn but make sure you have the right people to teach you and if the company fires a bullet in your back if it "keels over'' ( i could not resist).
Be wary.

I would agree. Somewhere in the deep depths of my dubious memory, there was a court case about 3 to 5 years ago involving an almost identical situation where someone had done some work on a boat and the welds failed, boat went base over turkey, someone lost their life and it all ended with the person who did the work.

Your call, be wise

Welds can still fail even when all the correct things were done. The welds can be flawless, welded by certified or qualified welders and pass all the tests under the sun but ay least this way if something failed and causes damage, personal injury or loss of life, the company and people involved at least have a leg to stand on. This at best would be ruled an accident as all the correct things were done and done to the industry standard.
My comment is to simply make you aware of the risks involved and if this is not your companies main line of work I would keep a good distance from it. If they tell you "youll be right mate" I would be worried.

If its a job through work let them organise a Certified Welding Supervisor to write you a welding procedure.

As its a fairly complex procedure its best overseen by a competent person ie welding supervisor.

Your consumable ( mig wire) will need to be matched to to the Bis 80.
The welding will have to comply with Australian Standard 1554, parts 4 &5. Do you ( your company) have copies as the price will astound you?

Also you have to be careful of the heat inputs and control them well.

Grahame

hi , ive been in the maintenance game for years now (18 years) and dealt with bisalloy over this period, weldall's or stainless electrodes are used in the welding application of bis. nothing to it, if you can weld well with a gp then you won't have any probs with a down hand weld using weldalls or stainless rods.

good luck.

Kraits
With respect,we are not dealing with a piece of mining equipment ,but something that really can't be allowed to fail.
Its a document that behooves any potential welder to read and follow it for fear of welding something that can bear extreme consequences if it fails.A C&P from the Bisalloy 80 manufacturer recommendations, follows.

<
COOLING RATE
Limitations on both preheat and heat input are necessary to ensure that the HAZ cools at an appropriate rate and that the correct hardness and microstructure are achieved. Too slow a cooling rate can result in a soft HAZ and thus a loss of tensile and fracture toughness properties. Too rapid a cooling rate produces a hard HAZ which may cause loss of ductility.


PREHEAT/HEAT INPUT
The preheat/heat input recommendations outlined in tables 2 and 3 will ensure that the cooling rate of the HAZ is satisfactory.>

The poster states he has a Kemppi 3200 water cooled,which is a MIG. Bisalloy recommend a GMAW wire from the W76xx grade.


Go into Google and read about the keel snapping off the Excalibur.It was down to shoddy work and men died and a man nearly went to jail over it.There a other similar instances also mentioned in other google links.

Extreme caution on the part of the welder fabricator needs to be exercised here.Fitness for purpose puts a real focus on this job.

Take care

Grahame

When I worked in NZ they welded in Bisalloy wear plates on dump truck bodies with flux cored SS MIG wire.

From memory they did pre-heat as well.

What I don't understand is why Bisalloy was chosen for a yacht keel? Seems over kill to me. I was in the marine industry for quite some time and it was always just mild steel plate that was used. (It has been a while though I might add)

Cheers

Justin

[QUOTE=

What I don't understand is why Bisalloy was chosen for a yacht keel? Seems over kill to me. I was in the marine industry for quite some time and it was always just mild steel plate that was used. (It has been a while though I might add)

Cheers

Justin[/QUOTE]


might be panning on carving up a reef

Originally Posted by Jarh73

When I worked in NZ they welded in Bisalloy wear plates on dump truck bodies with flux cored SS MIG wire.

From memory they did pre-heat as well.

Hi Justin

there's a vast difference in risk between a yacht keel and wear plates on a dump truck. If a wear plate weld fails, the consequences are minor to insignificant -- the production manager will be a little peeved that one of his trucks is off the raod being repaired, but otherwise who really cares.

But if a yacht keel falls off
the vessel capsizes
people are lost at sea
coroner and police are involved
responsible parties loose house, livelihood, reputation, go to jail (in some countries manslaughter is a capital offence)

I think a yacht keels call for prudence and as close to 100% perfect as you can get