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Willy
10-31-2012, 01:56 PM
As a long time subscriber to a trade publication called The Fabricator, I'm always gleaning their pages for useful nuggets of info and a better understanding and applicability to some of the processes I perform in my own shop.

The link below to the article about the process of welding free machining steels is one I thought I should share here. The article offers a metallurgists insight of why these types of steels (free machining) should be avoided if welding is anticipated.

I had originally thought of posting the link in the welding section, but as it does come up here in the general section so often I thought it would receive more exposure here.

You can machine it, but can you weld it? (http://www.thefabricator.com/article/metalsmaterials/you-can-machine-it-but-can-you-weld-itr)

johnnyd
10-31-2012, 03:03 PM
A very thought provoking article.

Thanx for sharing.....

sasquatch
10-31-2012, 09:04 PM
Thanks Willy interesting information.

wierdscience
10-31-2012, 09:11 PM
Free machining steels can be welded,but that doesn't mean they should be welded simple as that.Just about anytime they are seen in a critical application and joined without fasteners it's done via Brazing typically Copper Brazing as in Hydraulic fittings.

http://www.gh-ia.com/applications/brazing-hose-assembly.html

If it must be welded then as the article states Lo Hydrogen rod and low amperage are the general rule.

rohart
10-31-2012, 09:36 PM
The thoughts that that article provoke with me are that the writer is rather confused. His description of pearlite, ferrite and cementite is a mess. His description of sulphur and manganese is a mess. He leaves me in a total mess. I want to know why my low carbon steel seems to be so full of manganese that it causes my chips to break. Is that what causes BUE ? He doesn't say.

It's not until about a third of the way through that you begin to guess that the weldability problems are due to potential cracking.

I think he's one of those writers that gets his article reviewed by those that know before publication. He'd do better to get it reviewed by those that don't know. He might learn how little help his article is to those that don't know.

I do think he means well, and that he probably really knows his stuff. Just that he hasn't helped me. And I've got lots of bits of free-machining that I've welded. Maybe it hasn't cracked because it's mostly small parts. But I have to guess, because he hasn't helped me know, and that's what articles are meant for.

Rant over. Whew !

Mark McGrath
11-01-2012, 11:25 AM
For many years we supplied 40,000 parts per week to a customer.These parts were machined from free cutting steel and were welded to an assembly by our customer.Only spec was it had to be unleaded steel as the lead caused nodes in the welding.
Material was bog standard EN1A.

browne92
11-02-2012, 09:35 AM
For us workshop-in-the-back-yard-not-manufacturing types, what is "free machining"?

wierdscience
11-02-2012, 09:56 AM
Steel that has additives that make it machine easy such as Sulphur and Lead.Alloys such as 12l14 ,1144,1215,41l40 and so on.

michigan doug
11-02-2012, 03:21 PM
He also made the comment that leaded steel may weld fine with appropriate technique, but the big concern is the lead fumes. It would be bad practice to use a welded leaded steel component in something that could cause loss of life if the weld fails.

In practice, to fix my mower or whatever, it works fine.

doug

loose nut
11-02-2012, 06:57 PM
For us workshop-in-the-back-yard-not-manufacturing types, what is "free machining"?


It's steel that the store gives you for free if it is for machining.:D:D:D:D

Continued in next post.

loose nut
11-02-2012, 06:57 PM
:D:D:D:D

OK done.

lazlo
11-02-2012, 10:05 PM
He also made the comment that leaded steel may weld fine with appropriate technique, but the big concern is the lead fumes.

You can "weld" leaded steel, but the bead looks like hell, and I wouldn't trust it for anything structural.

lakeside53
11-02-2012, 10:23 PM
You can "weld" leaded steel, but the bead looks like hell, and I wouldn't trust it for anything structural.

That must be why mine all look like that! LOL

KiddZimaHater
11-02-2012, 11:08 PM
browne92,
Here's a list of 'Free-Machining' Steels:
12L13, 12L14, 1211, 1212, 1213, 1117, 1118, 1119

lakeside53
11-02-2012, 11:36 PM
Don't forget 303!

RussZHC
11-03-2012, 12:48 AM
browne92:
I have found Speedy Metals site good for some basic information, its a layer or two down so you have to look a bit. Within that information they talk about things like common uses, machinability and welding.
The difficulty of machining is sort of a continuum with a material being rated relative to...so, as example, 1144 is rated at 83% of B1112 1045 cold roll is rated at 64% of B1112. In the case of 1045 they also mention "not readily welded..." but then go on to say larger sections can be with preheating. It can give one a bit of a starting point relative to other known materials you have worked with...or at least that is the theory.

More condensed info http://en.wikipedia.org/wiki/Machinability

lazlo
11-03-2012, 11:18 AM
In the case of 1045 they also mention "not readily welded..." but then go on to say larger sections can be with preheating.

1045 is a different issue. I just successfully welded some bending brake fingers that were presumably 4140/4150. The issue there, like welding cast iron, is that you're putting a bunch of carbon in solution, and if it cools too quickly you're essentialy quenching it, and form brittle martensite or cementite at the weld boundary that will crack as the part cools down.

The way around that is to either use non martensitic filler (nickel, 308 stainless), or to thoroughly preheat the part, and then slowly cool it down.

wierdscience
11-03-2012, 11:41 AM
I don't know how they can say 1045 isn't readily welded since 1045,1050 and 1095 are all used in chrome hydraulic cylinder rods which are welded by the millions.

Maybe requiring local pre-heat means "not readily" to some?

lazlo
11-03-2012, 11:49 AM
I don't know how they can say 1045 isn't readily welded

Clearly meaning that you can't whip out your tombstone and drop a farm weld on it :)

wierdscience
11-03-2012, 11:51 AM
Clearly meaning that you can't whip out your tombstone and drop a farm weld on it :)

Yet it happens successfully daily:D

lazlo
11-03-2012, 12:06 PM
Yet it happens successfully daily:D

It happens daily. Whether the welds hold or not is a totally different story :)

At least once a month I see a post on Weldtalk where a guy claims he welds cast iron with mild steel wire, no preheat. Hmm... ;)

loose nut
11-03-2012, 02:30 PM
You hear that on this forum too. Cast iron should be welded with a "good" cast iron rod and the proper procedure otherwise your looking for trouble.

loose nut
11-03-2012, 02:30 PM
Don't forget 303!

and 416 SS