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Up Topic Welding Industry / Welding Fundamentals / Distortion Control
- - By John Stewart (*) Date 05-18-2008 05:29
I happened to fall on your site and noticed old requests about my books Distortion Control and Flame Straightening . Responders were giving an address

I vacated 10 years ago.

Should you get similar requests in the future it may be helpful if you direct them to my website.http://members.aol.com/stewartmtl/

These books have been on the market for a long time but they are still popular and as effective today as they were 20 years ago.

I am also the author of

Welder Fitter's Training Guide

A book for welders who wish to advance to the rewarding fitter level.

I worked for 30 years as a welding and fitting specialist.

Over the years I manually welded thousands of parts for rail cars

and built and welded numerous apparatus for paper machinery and rolling mills and put bridge spans together as well as large turbines.

My shop floor experiences were learned through trial and error and my books have documented the best results.

I was a AWS member for many years but have now been retired for over 20 years.

Fittingly,

John Stewart
Parent - - By Lawrence (*****) Date 05-18-2008 07:01
John,

I really like your books.  I use them to teach and to fabricate.

Thanks!
Parent - - By Boon (**) Date 07-16-2008 17:05
I am planning to order a book on distortion control.
But meanwhile I need some advice on preventing or minimising distortion from welding urgently.
We are fabricating some units of SS 316L 5.0 mm thick diameter 1500 mm round sections welded to 6 mm thick flange (75 mm height) at the end with fillet weld.
My concern is how to prevent distortion and maintain levelness of the flange surface after welding. Should more tack welds be placed at short distance apart, add supports to hold the flange at right angle to the round section or both to prevent distortions?
How about sequence of welding around the circumference?

Regards
Boon
Parent - By aevald (*****) Date 07-16-2008 20:09
Hello Boon, are you able to fit these sections and then bolt them together one to another, or what might be referred to as back to back? If so, you could possible do exactly that and also include a spacing ring that is on the inside portion of the bolt circle or flange which would allow the flanges to be drawn together so that the very outside diameter of them is slightly closer together than the inside portion of the flanges. This might allow for some of the shrinkage you will experience and allow the flange to stay square to the round section. If these aren't bolted flanges you might be able to either use clamps or lightly tack the edges together so that you could remove the tacks after the units have cooled. I have scanned in an image to show an example, hopefully I have understood your description correctly. Best regards, aevald
Attachment: SSshimexample.bmp (692k)
Parent - By pipewelder_1999 (****) Date 05-18-2008 14:11
Mr. Stewart,,

Its nice to see you here and welcome to the forum.
Parent - - By swsweld (****) Date 05-18-2008 17:02
Thanks for the info John. I have seen your books referred to on the forum in high regard. I failed to record the name of the book for ordering purposes. Your link just solved that. I will be ordering a few books this week.

Welcome to the forum and "fall" in anytime.
Parent - - By devo (***) Date 05-19-2008 12:16
I picked up the distortion control book at amazon.com.  It is an outstanding resource, well written and worth the money to anyone who fabricates steel weldments.  If you are looking for it on amazon, they misspelled the title, making it hard to find.  They have it listed as "destoration control".  One thing I noticed in the book is in regards to flame straightening.  I have the AWS book on flame bending and they recommend a maximum temperature of 1200 F. for mild steel.  Mr. Stewart gives no number for a max. temp, but simply states to get the piece "cherry red".  Isn't cherry red quite a bit hotter than 1200?  By the way, I flame bent a 12' piece of 2"x4" rect. tube to a six foot radius for a job recently, my first try at this technique, and it worked quite well.  It took just over 100 heats, about nine hours, but the results were outstanding.  The curve was even throughout, and it did not distort in the other axis.
Parent - - By HgTX (***) Date 05-19-2008 20:46
I have it from a number of reliable sources that "cherry red" is way too hot for most structural steels.  If I catch someone with cherry red steel and no temperature checking device (crayons, IR gun) to verify that they haven't overheated, they gots themselves a nonconformance on their hands.

Hg
Parent - - By jrw159 (*****) Date 05-19-2008 20:55
DING DING DING Give that man a cigar!

One thing to remember is these books were published quite some time ago. I have not used them personally, but I am sure they were and are very informative and usefull. But this could have been the best way the author felt at the time that he could relay "Industry Standard" to the every day student or worker. IMHO

And maybe not. FWIW

jrw

Parent - - By HgTX (***) Date 05-19-2008 21:00
D1.5 had a reference to "dull red" for 1200F as recently as 2002, but it went away in 2008 because revised common wisdom says red is too hot.  Wonder how common wisdom came to change over time?  Did no one actually check till recently?

Hg
Parent - By jrw159 (*****) Date 05-19-2008 21:21
Good question, and proof positive that this is an ever evolving industry, and always will be.

Just think what they may be saying about what we do today in say twenty, thirty, or fifty years.

I can only imagine. LOL :-)

John
Parent - - By aevald (*****) Date 05-19-2008 21:29
I would throw this out there for folks to consider. Until relatively recently, A-36 was the common material for much of the structural work that has been done. As has been the topic on numerous occasions on different threads, A-36 is "supposedly" relatively unaffected by temperature and cooling rates, possibly this is the reason why the "cherry red" description is included. With the inclusion of various alloyed materials being used in much of today's construction, I could certainly see the need for tighter heating and cooling restrictions. A couple more $.02 to consider. Best regards, Allan
Parent - By jrw159 (*****) Date 05-19-2008 21:34
Allan,
  Makes sense to me. And it kind of fits with the theory.

John
Parent - - By HgTX (***) Date 05-19-2008 21:36
That sounds suspiciously reasonable.

Hg
Parent - By jrw159 (*****) Date 05-19-2008 21:39
Scary, ain't it? LOL:-)
Parent - - By DaveBoyer (*****) Date 05-20-2008 04:26
The precieved color at a given temperature has a lot to do with the ambient light conditions. Dull red [or any other red-orange color] is a lot hotter in full sunlight than in near dark
Parent - - By devo (***) Date 05-20-2008 15:16
When performing the flame bending mentioned above, I initially did it without a shaded lens so I could see the color change(my local supplier only had a tempilstik in 500 deg.) I only had one shop light on, and it worked okay, but after about ten minutes of that, that torch flame got pretty bright.  By the way, it was .125" wall thickness and I used a #2 victor welding tip.  With the #5 cutting shield on, and with clean hot rolled steel with the mill scale intact, I would heat the metal until I saw a "shadow" develop, and I just pushed that shadow around the tube, and the results were very good.  Judging by the rainbow effect of my heat lines, the thermal gradients were nice and steep, and the bending quite uniform.  When I went back over for my second round of heats, you could see closely packed stress lines in the mill scale from the contraction.  Once I get around to ordering a 1200 deg. tempilstik I would like to see how close I am getting to the 1200 limit.
Parent - - By John Stewart (*) Date 05-25-2008 19:33
I appreciate all the comments mostly favorable and I would like to clear something up.

We used the cherry red color only on mild steel.This was deemed safe by two prominent individuals in our plant, the welding engineer and the

metallurgical  engineer.

For stainless or specially hardened steels,straightening these by torch flame could damage the integrity of the metal if too hot. A written procedure

outlining lesser temperatures is absolutely necessary but [unfortunately less effective] by a responsible person who is aware of the consequences.

The procedure would require careful monitoring throughout the process with heat stiks and no one should attempt the heating without permission.

And now for a little humor which in fact is a true story.

One of our welders was informed to preheat a gear section to 800f degrees before welding and use Tempilstiks to monitor the temperature.

When the Tempilstik would melt he could proceed to weld the joint. We found that he started welding sooner than we expected so we went to check.

He informed us that he couldn't find a Tempilstik of 800f degrees so he got two. One of 500f and one of 300f.
Parent - By DaveBoyer (*****) Date 05-26-2008 03:50
He might not have been too strong on "common sense", but at least He could add. :-)
Parent - By swsweld (****) Date 05-27-2008 03:06
Was that wrong?
Should he have used two 400F sticks instead?
Up Topic Welding Industry / Welding Fundamentals / Distortion Control

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