312 wire on mild steel

[Garreth]

Hi All

A techie question ! Assuming all things are equal (materials, weld prep, weld quality, gas type/flow, optimum parameters etc etc) would using a 312 filler give a "stronger" weld than using, say, a more "standard" wire such as A15 ?

I suppose what I am wanting to know is will using a filler material with a higher tensile strength actually result in a joint with greater mechanical properties ?

Also if 312 does have benefits are there any other potential issues with using it on mild steel (other than obviously the increased costs) ?

I am tring to reproduce a mild steel bracket - but am looking to make it stronger than the original item. It is obviously possible to "design" it stronger (better materials,bigger, thicker, bigger fillets etc) but I wish it to look identical. I've made some very minor tweeks here and there but just wondered if a change of filler might improve it.

I don't neccessarily need to quantify the results but if the general consensus is that it will make an improvement then I'll use 312.

I would value your input !

Cheers.

Garreth

 

[squazy84]

I don't know the answer but have wondered the same, its unusual to see someone able to articulate a point or question in unbroken English on the net (myself included but im Irish lol)

 

[TechnicAl]

The 312 will be about twice the tensile strength of mild steel A15. It will also be higher than the mild steel plate you are welding. Therefore, if the component was to fail due to tensile loading it would fail in the mild steel. So there is not much point in going to the expense of using 312 if this is the only reason.

If your bracket isnt strong enough using 312 filler definitely wont resolve the problem. It will only be as strong as its weakest part. You need to redesign it.

Also the difference is strength can lead to a weak point if under fatigue loading (constant movement).

 

[Garreth]

Thanks TechnicAl !

I was hoping you would answer

There has been no history of failure in this part - in my opinion it is vastly over engineered for the job it does !

I've been tasked with casting a fresh eye over the design making improvements where possible, but the new parts have to be directly interchangeable with the old items.

What I'd like to be able to say is "yes Mr Customer the old part was OK and never failed, but now we're using 312 filler wire which results in a stronger item". I don't then want him to turn round and say "Ah - 312 is actually worse due to metallurgical issues X,Y & Z"

Its a high value product, and the cost of materials isn't really important.

So basically I want to make a sales pitch out of the small improvements we're making, but don't want it to bite me on the **** !

Cheers.

Garreth

 

[TechnicAl]

I would be more impressed if you said to me "I have investigated this product and I can find no way of improving it"

Im a great believer in "if it aint broke dont fix it".

 

[Garreth]

I would be more impressed if you said to me "I have investigated this product and I can find no way of improving it"

Im a great believer in "if it aint broke dont fix it".

Fair play.

I'll keep going with the search for improvements then.

Thanks !

Garreth

 

[Drains]

Garreth, if you need (or in this case, your client wants) to make the part stronger - as said, there's no need to make the weld stronger than the base metal as you just move potential fail points elsewhere, so... make both stronger. Instead if a mild steel part, make a stainless part, or find something better than straight m/s anyway. All sorts of strong alloys and metals out there. If price is no object, go for titanium, or inconel, or something fancy....
Stainless would be simple, but not as simple as changing nothing.

If I were you, your client would have got the sharp edge of my tongue by now for dicking around. Al is more polite than me.

 

[Shox Dr]

I would be more impressed if you said to me "I have investigated this product and I can find no way of improving it"

Im a great believer in "if it aint broke dont fix it".

I think time in use has shown that to be true.

Why do they want it making stronger when it hasn't failed before? Marketing Hype by any chance?

If I was looking at the part, the question would be; How much lighter can we make it before it does fail. At least you can then say it is still up to the job, but is zxy lighter, and costs zxy less to produce. And they would still have their marketing bullcrap

 

[langy]

x 2, good advice

I would be more impressed if you said to me "I have investigated this product and I can find no way of improving it"

Im a great believer in "if it aint broke dont fix it".

 

[Phataz1]

I read on here that using stainless filler on mild steel causes galvanic reactions and corrodes the mild steel faster than if mild steel filler was used. Is this true?

And if so, is this only a problem if the piece isn't protected in some way by paint or something?


Cheers

 

[TechnicAl]

I read on here that using stainless filler on mild steel causes galvanic reactions and corrodes the mild steel faster than if mild steel filler was used. Is this true?

And if so, is this only a problem if the piece isn't protected in some way by paint or something?


Cheers

Yes and yes
and in reality the accelerated corrosion isnt instant or anything even approaching that.

 

[Tino]

You could use a 501 steel and A31 wire. Both a bit stronger than m/s.

 

[Phataz1]

Yes and yes
and in reality the accelerated corrosion isnt instant or anything even approaching that.

I see, thanks